Pyrrolizidine alkaloids(PAs)and their N-oxides(PANOs)are phytotoxins produced by various plant species and have been emerged as environmental pollutants.The sorption/desorption behaviors of PAs/PANOs in soil are cruci...Pyrrolizidine alkaloids(PAs)and their N-oxides(PANOs)are phytotoxins produced by various plant species and have been emerged as environmental pollutants.The sorption/desorption behaviors of PAs/PANOs in soil are crucial due to the horizontal transfer of these natural products from PA-producing plants to soil and subsequently absorbed by plant roots.This study firstly investigated the sorption/desorption behaviors of PAs/PANOs in tea plantation soils with distinct characteristics.Sorption amounts for seneciphylline(Sp)and seneciphylline-N-oxide(SpNO)in three acidic soils ranged from 2.9 to 5.9μg/g and 1.7 to 2.8μg/g,respectively.Desorption percentages for Sp and SpNO were from 22.2%to 30.5%and 36.1%to 43.9%.In the mixed PAs/PANOs systems,stronger sorption of PAs over PANOs was occurred in tested soils.Additionally,the Freundlich models more precisely described the sorption/desorption isotherms.Cation exchange capacity,sand content and total nitrogen were identified as major influencing factors by linear regression models.Overall,the soils exhibiting higher sorption capacities for compounds with greater hydrophobicity.PANOs were more likely to migrate within soils and be absorbed by tea plants.It contributes to the understanding of environmental fate of PAs/PANOs in tea plantations and provides basic data and clues for the development of PAs/PANOs reduction technology.展开更多
Ruthenium dioxide(RuO_(2))is one of the most promising acidic oxygen evolution reaction(OER)catalysts to replace the expensive and prevalent iridium(Ir)-based materials.However,the lattice oxygen oxidation induced Ru ...Ruthenium dioxide(RuO_(2))is one of the most promising acidic oxygen evolution reaction(OER)catalysts to replace the expensive and prevalent iridium(Ir)-based materials.However,the lattice oxygen oxidation induced Ru dissolution during OER compromises the activity and stability.Amorphous materials have been identified as a viable strategy to promote the stability of RuO_(2)in acidic OER applications.This study reported a nanoporous amorphous-rich RuMnO_(x)(A-RuMnO_(x))aerogel for efficient and stable acidic OER.Compared with highly crystalline RuMnO_(x),the weakened Ru–O covalency of A-RuMnO_(x)by forming amorphous structure is favorable to inhibiting the oxidation of lattice oxygen.Meanwhile,this also optimizes the electronic structure of Ru sites from overoxidation and reduces the reaction energy barrier of the rate-determining step.As a result,A-RuMnO_(x)aerogel exhibits an ultra-low overpotential of 145 mV at 10 mA cm^(-2)and durability exceeding 100 h,as well as high mass activity up to 153 mA mg^(-1)_(Ru)at 1.5 V vs.reversible hydrogen electrode(RHE).This work provides valuable guidance for preparing highly active and stable Ru-based catalysts for acidic OER.展开更多
Solving the problem of aggregation and nonuniform dispersion of platinum(Pt)nanoparticles(NPs)is the key to obtaining high catalytic activity.Graphene aerogels(GAs)with large accessible specific surface area and abund...Solving the problem of aggregation and nonuniform dispersion of platinum(Pt)nanoparticles(NPs)is the key to obtaining high catalytic activity.Graphene aerogels(GAs)with large accessible specific surface area and abundant surface defects are considered to be excellent substrate materials for reducing Pt agglomeration and enhancing catalytic activity.Herein,Pt-based GA composites(Pt-GA-x)featuring homogeneous particle dispersion and high activity were successfully synthesized through a one-step reduction method.Fourier transform infrared(FTIR),Raman,and X-ray photoelectron spectroscopy(XPS)test results indicate that the presence of a large number of oxygen-containing functionalities in GA for anchoring Pt NPs,and the interaction with GA produces electronically structured Pt and defect-rich GA substrates.The obtained electrocatalyst Pt-GA-2 possesses a large specific surface area(443.46 m^(2)·g^(−1)),low Pt loading(3.08 wt%),and uniformly dispersed Pt NPs(average 42 nm).As an advanced hydrogen evolution reaction(HER)electrocatalyst,an overpotential of 34 mV is achieved at a current density of 10 mA·cm^(−2)in 0.5 M H_(2)SO_(4)electrolyte,together with a low Tafel slope of 33.2 mV·dec^(−1).Hence,high mass activity(5623 mA·mgPt^(−1))and turnover frequency(TOF=2.57 s^(−1)at η=100 mV)can be obtained,which are 6.81 and 6.76 times higher than those of commercial Pt/C catalysts.All these are attributed to enormous surface defects over GA and electron enrichment on Pt NPs.The present study highlights the unique advantages of GA in electrochemical energy conversion and provides new avenues to fabricate advanced HER electrocatalysts.展开更多
The potential of 2-amino-1-propanol(AP)as a novel depressant in selectively floating ilmenite from titanaugite under weakly acidic conditions was investigated.Micro-flotation results show that AP significantly reduces...The potential of 2-amino-1-propanol(AP)as a novel depressant in selectively floating ilmenite from titanaugite under weakly acidic conditions was investigated.Micro-flotation results show that AP significantly reduces the recovery of titanaugite while having no evident impact on ilmenite flotation.Subsequent bench-scale flotation tests further confirm a remarkable improvement in separation efficiency upon the introduction of AP.Contact angle and adsorption tests reveal a stronger affinity of AP towards the titanaugite surface in comparison to ilmenite.Zeta potential measurements and X-ray photoelectron spectroscopy(XPS)analyses exhibit favorable adsorption characteristics of AP on titanaugite,resulting from a synergy of electrostatic attraction and chemical interaction.In contrast,electrostatic repulsion hinders any significant interaction between AP and the ilmenite surface.These findings highlight the potential of AP as a highly efficient depressant for ilmenite flotation,paving the way for reduced reliance on sulfuric acid in the industry.展开更多
The effects of the structure and concentration of impurities on the alkylation of naphthalene with 1-octene catalyzed by chloroaluminate ionic liquid(IL)were investigated.The presence of impurities containing oxygen a...The effects of the structure and concentration of impurities on the alkylation of naphthalene with 1-octene catalyzed by chloroaluminate ionic liquid(IL)were investigated.The presence of impurities containing oxygen and nitrogen led to a decrease in the catalytic performance of chloroaluminate IL.As the water concentration increased to 65 mg·g^(-1),the total selectivity of multi-octylnaphthalene gradually decreased to 42.33%,and the average friction coefficient of the multi-octylnaphthalene base oil gradually increased to 0.201.When the concentration of impurities increased to a critical value,the chloroaluminate IL began to deactivate,leading to a decrease in naphthalene conversion.The critical concentrations for ethanolamine,water,methanol,ether,and diisopentyl sulfide were 33 mg·g^(-1),65 mg·g^(-1),67mg·g^(-1),87 mg·g^(-1),and 123 mg·g^(-1),respectively.Impurities with higher basicity resulted in an earlier onset of chloroaluminate IL deactivation.The changes of Lewis and Brønsted acids in chloroaluminate IL under the influence of impurities were investigated using in situ IR and 27Al NMR spectroscopy.2,6-dimethylpyridine as an indicator could detect the changes of Brønsted acid in chloroaluminate IL better,but the changes of Lewis acid were not obvious because of the overlap between the characteristic peaks.2,6-dichloropyridine as an indicator could exclusively detect the changes of Lewis acid in chloroaluminate IL.With the increase inwater concentration,the Lewis acid in chloroaluminate IL was continuously consumed and converted into Brønsted acid,and the Lewis acid gradually decreased,while the Brønsted acid showed a change of increasing first and then decreasing.展开更多
Graphene encapsulation has been shown to be an effective technique for improving the corrosion resistance of non-noble metal catalysts for the acidic water electrolysis.The key challenge lies in enhancing the electroc...Graphene encapsulation has been shown to be an effective technique for improving the corrosion resistance of non-noble metal catalysts for the acidic water electrolysis.The key challenge lies in enhancing the electrocatalytic activity of graphene-encapsulated metals while maintaining their durability in acidic media.Herein,an electron-transfer-tuning strategy is investigated at the graphene/NiMo interface,aiming to improve the hydrogen evolution reaction(HER)performance of graphene-encapsulated NiMo catalysts.The doping of Ti,a low electronegativity element,into NiMo substrate was confirmed to increase electron transfer from the metal core toward the graphene.The electron-rich state on graphene facilitates the adsorption of positively charged protons on graphene,thereby enabling a Pt/C-comparable performance in 0.5 M H_(2)SO_(4),with only a 3.8%degradation in performance over a 120-h continuous test.The proton exchange membrane(PEM)water electrolyzer assembled by the N-doped grapheneencapsulated Ti-doped NiMo exhibits a smaller cell voltage to achieve a current density of 2.0 A cm^(-2),in comparison to the Pt/C based counterpart.This study proposes a novel electron-transfer-tuning strategy to improve the HER activity of graphene-encapsulated non-noble metal catalysts without sacrificing durability in acidic electrolytes.展开更多
Proton exchange membrane water electrolyzer(PEMWE)is crucial for the storage and conversion of renewable energy.However,the harsh anode environment and the oxygen evolution reaction(OER),which involves a four-electron...Proton exchange membrane water electrolyzer(PEMWE)is crucial for the storage and conversion of renewable energy.However,the harsh anode environment and the oxygen evolution reaction(OER),which involves a four-electron transfer,result in a significant overpotential that limits the overall efficiency of hydrogen production.Identifying active sites in the OER is crucial for understanding the reaction mechanism and guiding the development of novel electrocatalysts with high activity,cost-effectiveness,and durability.Herein,we summarize the widely accepted OER mechanism in acidic media,in situ characterization and monitoring of active sites during the reaction,and provide a general understanding of the active sites on various catalysts in the OER,including Ir-based metals,Ir-based oxides,carbon/oxide-supported Ir,Ir-based perovskite oxides,and Ir-based pyrochlore oxides.For each type of electrocatalysts,reaction pathways and actual active sites are proposed based on in situ characterization techniques and theoretical calculations.Finally,the challenges and strategic research directions associated with the design of highly efficient Ir-based electrocatalysts are discussed,offering new insights for the further scientific advancement and practical application of acidic OER.展开更多
The increasing level of atmospheric carbon dioxide(CO_(2))caused by intensified human activities has exacerbated the greenhouse effect,calling for the technology of CO_(2)fixation.Among the proposed technologies,elect...The increasing level of atmospheric carbon dioxide(CO_(2))caused by intensified human activities has exacerbated the greenhouse effect,calling for the technology of CO_(2)fixation.Among the proposed technologies,electrocatalytic CO_(2)reduction in acidic electrolytes has garnered significant attention for its potential in sustainable carbon utilization and renewable energy storage.This review provides a summary of recent advancements in acidic CO_(2)reduction,with a focus on catalyst design strategies,the optimization of the local reaction environment,and the effect of cations.We first evaluated the performance and discussed the challenges for acidic CO_(2)reduction in H-type cells,flow cells,and membrane electrode assembly.Afterward,we highlight the innovative strategies for promoting CO_(2)reduction through optimizing the intrinsic activity and regulating the local environment of catalysts.The critical role of cations in enhancing CO_(2)reduction selectivity is also discussed.The review concludes with an outlook on future research directions,especially the need for the design of catalysts and systems that are stable,scalable,and highly efficient.展开更多
Direct converting carbon dioxide(CO_(2))and propane(C_(3)H_(8))into aromatics with high carbon utilization offers a desirable opportunity to simultaneously mitigate CO_(2)emission and adequately utilize C_(3)H_(8) in ...Direct converting carbon dioxide(CO_(2))and propane(C_(3)H_(8))into aromatics with high carbon utilization offers a desirable opportunity to simultaneously mitigate CO_(2)emission and adequately utilize C_(3)H_(8) in shale gas.Owing to their thermodynamic resistance,converting CO_(2)and C_(3)H_(8) respectively remains difficult.Here,we achieve 60.2%aromatics selectivity and 48.8%propane conversion over H-ZSM-5-25 via a zeolite-catalyzing the coupling of CO_(2)and C_(3)H_(8).Operando dual-beam FTIR spectroscopy combined with ^(13)C-labeled CO_(2)tracing experiments revealed that CO_(2)is directly involved in the generation of aromatics,with its carbon atoms selectively embedded into the aromatic ring,bypassing the reverse water-gas shift pathway.Accordingly,a cooperative aromatization mechanism is proposed.Thereinto,lactones,produced from CO_(2)and olefins,are proven to be the key intermediate.This work not only provides an opportunity for simultaneous conversion of CO_(2)and C_(3)H_(8),but also expends coupling strategy designing of CO_(2)and alkanes over acidic zeolites.展开更多
Selective electrocatalysis of two-electron oxygen reduction reaction(2e^(-)ORR)has been recognized as a sustainable and on-site process for hydrogen peroxide(H_(2)O_(2))production.Great progress has been achieved for ...Selective electrocatalysis of two-electron oxygen reduction reaction(2e^(-)ORR)has been recognized as a sustainable and on-site process for hydrogen peroxide(H_(2)O_(2))production.Great progress has been achieved for 2e^(-)ORR in alkaline media.However,it is challenged by insufficient activity and selectiv-ity of the catalysts in acidic electrolytes.Herein,we report sulfur-poisoned PtNi/C catalysts(PtNiSx/C)that could regulate ORR from the 4e^(-)to 2e^(-)pathway.The identified PtNiS0.6/C offers high activity in terms of onset potential of∼0.69 V(vs.RHE)and∼80%selectivity.The mass activity is also compara-ble and outperforms representative Pt-based precious and transition-metal-based catalysts.In addition,it is interestingly found that the Faradaic efficiency further increased to 95%during the long-term elec-trolysis test due to Ni atom surface migration.The electrochemical production of the H_(2)O_(2)system was applied to the electro-Fenton process,which has realized the effective degradation of organic pollutants.This work offers a strategy by sulfur poisoning PtNi/C catalyst to realize Pt-based 2e^(-)ORR active catalysts to electrolysis of H_(2)O_(2)in acidic media.展开更多
BACKGROUND Pancreatic cancer tissues mainly consist of fibrotic and dense stroma,which limits their therapeutic efficacy.The stromal fibroblasts of pancreatic tumors frequently express the secreted protein acidic and ...BACKGROUND Pancreatic cancer tissues mainly consist of fibrotic and dense stroma,which limits their therapeutic efficacy.The stromal fibroblasts of pancreatic tumors frequently express the secreted protein acidic and rich in cysteine(SPARC).AIM To assess the impact of SPARC and its oncological relevance in patients undergoing pancreatic cancer resection.METHODS Ninety-one pancreatic ductal adenocarcinoma specimens were obtained from patients with curative resection between January 2009 and December 2015 as a retrospective study.SPARC expression patterns were analyzed using immunohistochemistry.Oncological outcomes were analyzed based on SPARC expression patterns.Oncological outcomes,based on SPARC expression,were analyzed in The Cancer Genome Atlas-Pancreatic Adenocarcinoma cohort(retrieved from a public database).RESULTS Patients with stromal SPARC expression(sSPARC+)had poorer overall survival than that in those without it(sSPARC-)(P=0.035).However,among patients who received adjuvant treatment,no difference was observed in survival between the sSPARC+and the sSPARC-groups(P=0.14).In The Cancer Genome Atlas-Pancreatic Adenocarcinoma samples,the high SPARC expression group exhibited noticeably lower overall survival than that in the low expression group(cutoff:14.1295,P=0.0222).Furthermore,SPARC expression was strongly correlated with the percentage the CD10+stromal component(R2=0.804,P<0.001).CONCLUSION Adjuvant chemotherapy improves survivals in sSPARC+pancreatic cancer patients,indicating suggesting sSPARC expression as a prognostic biomarker and potential indicator for neoadjuvant treatment planning.展开更多
Electrochemical carbon dioxide reduction reaction(CO_(2)RR)converts CO_(2) into valuable chemicals by consuming renewable electricity at mild conditions,making it a promising approach to achieving carbon neutrality.Ho...Electrochemical carbon dioxide reduction reaction(CO_(2)RR)converts CO_(2) into valuable chemicals by consuming renewable electricity at mild conditions,making it a promising approach to achieving carbon neutrality.However,the reaction of CO_(2) with hydroxide ions to form carbonates leads to low carbon utilization and energy efficiency in near-neutral or alkaline CO_(2)RR.The high concentration of protons in acidic media can effectively mitigate carbonate formation and deposition,thereby significantly minimizing carbon loss and energy consumption.Unfortunately,hydrogen evolution reaction(HER)is more kinetically favorable than CO_(2)RR in acidic media.Herein,we comprehensively overview recent progress in acidic CO_(2)RR and propose two strategies derived from the competing reaction pathways of HER and CO_(2)RR:one focuses on regulating the H+mass transport,while the other aims to modulate the intrinsic kinetic activity of CO_(2)RR.The two strategies are designed to compete for the limited active sites on the catalyst surface,inhibit side reactions,and enhance the activity and selectivity of CO_(2)RR.The representative approaches include modulating the interface electric field,constructing a local alkaline environment,and regulating competing adsorption sites.Finally,we also review the technical challenges and future perspectives of acidic CO_(2)RR coupled with membrane electrode assemblies(MEAs).展开更多
BACKGROUND Diabetic retinopathy(DR)is the leading cause of vision loss in patients with diabetes.The vascular endothelial growth factor(VEGF)pathway plays a critical role in the pathogenesis of DR,and ranibizumab,an a...BACKGROUND Diabetic retinopathy(DR)is the leading cause of vision loss in patients with diabetes.The vascular endothelial growth factor(VEGF)pathway plays a critical role in the pathogenesis of DR,and ranibizumab,an anti-VEGF agent,has shown promise in its treatment.Signal transducer and activator of transcription 3(STAT3)is involved in inflammatory processes and cellular signaling,while glial fibrillary acidic protein(GFAP)is a marker of glial cell activation,both contributing to retinal damage in DR.However,the mechanisms by which ranibizumab affect early-stage DR through the VEGF/STAT3/GFAP pathway are not fully understood.AIM To investigate the role of ranibizumab in early DR via the VEGF/STAT3/GFAP pathway.METHODS Adult retinal pigment epithelial 19(ARPE-19)cells and human retinal microvascular endothelial cells(HRMECs)were cultured under high-glucose conditions to simulate a diabetic environment.The effects of ranibizumab on cytokine mRNA and protein expression were analyzed by quantitative polymerase chain reaction and Western blot analysis.A diabetic rat model was induced with streptozotocin(60 mg/kg).Retinal changes,including retinal ganglion cell(RGC)apoptosis,vascular alterations,and cytokine expression,were evaluated using fundus fluorescein angiography,hematoxylin and eosin and periodic acid Schiff staining,immunofluorescence,confocal imaging,and Western blot analysis.RESULTS High-glucose conditions significantly increased the mRNA and protein levels of VEGF,STAT3,GFAP,and other cytokines in ARPE-19 and HRMECs.However,these levels were partially suppressed by ranibizumab.RGC apoptosis,vascular leakage,and elevated cytokine expression were observed during early-stage DR in diabetic rats.Ranibizumab treatment in diabetic rats reduced cytokine expression,restored RGCs,and repaired vascular networks.CONCLUSION Intravitreal ranibizumab modulates the VEGF/STAT3/GFAP pathway,suppresses cytokine expression,and promotes retinal repair,effectively delaying or preventing early DR progression.展开更多
The development of highly active and stable bifunctional electrocatalysts in acidic media is crucial to hydrogen production by proton exchange membrane.In this study,we designed a RuO_(2)-IrO_(2)heterostructure cataly...The development of highly active and stable bifunctional electrocatalysts in acidic media is crucial to hydrogen production by proton exchange membrane.In this study,we designed a RuO_(2)-IrO_(2)heterostructure catalyst coupled by carbon quantum dots(CQDs).The catalyst showed excellent electrocatalytic performance for water splitting under acidic conditions.The overpotentials of oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)were as low as 180 and 15 mV at 10 mA/cm^(2)in 0.5 M H_(2)SO_(4),respectively.The acid electrolytic cell developed with RuO_(2)-IrO_(2)@CQDs as anode and cathode operated stably at 10 m A/cm^(2)for 120 h.In situ measurements and theoretical calculation reveal that the unique lattice oxygen mechanism path of RuO_(2)-IrO_(2)@CQDs can bypass the OOH^(*)intermediate and breaks the linear relationship of adsorbent evolution mechanism path,resulting in higher OER catalytic activity.展开更多
The persistent stability of ruthenium dioxide(RuO_(2))in acidic oxygen evolution reactions(OER)is compromised by the involvement of lattice oxygen(LO)and metal dissolution during the OER process.Heteroatom doping has ...The persistent stability of ruthenium dioxide(RuO_(2))in acidic oxygen evolution reactions(OER)is compromised by the involvement of lattice oxygen(LO)and metal dissolution during the OER process.Heteroatom doping has been recognized as a viable strategy to foster the stability of RuO_(2)for acidic OER applications.This study presented an ion that does not readily gain or lose electrons,Ba^(2+),into RuO_(2)(Ba-RuO_(2))nanosheet(NS)catalyst that increased the number of exposed active sites,achieving a current density of 10 mA/cm^(2)with an overpotential of only 229 mV and sustaining this output for over 250 h.According to density functional theory(DFT)and X-ray absorption spectroscopy,Ba doping resulted in a longer Ru-O bond length,which in turn diminished the covalency of the bond.This alteration curtailed the involvement of LO and the dissolution of ruthenium(Ru),thereby markedly improving the durability of the catalyst over extended periods.Additionally,attenuated total reflectance-surface enhanced infrared absorption spectroscopy analysis substantiated that the OER mechanism shifted from a LO-mediated pathway to an adsorbate evolution pathway due to Ba doping,thereby circumventing Ru over-oxidation and further enhancing the stability of RuO_(2).Furthermore,DFT findings uncovered that Ba doping optimizes the adsorption energy of intermediates,thus enhancing the OER activity in acidic environments.This study offers a potent strategy to guide future developments on Ru-based oxide catalysts'stability in an acidic environment.展开更多
The high-efficiency conversion of biomass resources to biofuels has attracted widespread attention, and the active sites and synergistic effect of catalysts significantly impact their surface arrangement and electroni...The high-efficiency conversion of biomass resources to biofuels has attracted widespread attention, and the active sites and synergistic effect of catalysts significantly impact their surface arrangement and electronic structure. Here, a nickel-based transition metal carbide catalyst(Ni/TMC) with high Lewis acidity was prepared by self-assembly of transition metal carbide(TMC) and nickel, which exhibited excellent performance on synergistic hydrogenation and hydrogenolysis of 5-hydroxymethylfurfural(HMF) into liquid biofuel 2,5-dimethylfuran(DMF).Notably, Ni/WC with the highest Lewis acidity(4728.3 μmol g^(-1)) can achieve 100% conversion of HMF to 97.6% yield of DMF, with a turnover frequency of up to 46.5 h^(-1). The characterization results demonstrate that the rich Lewis acid sites yielded by the synergistic effect between Ni species and TMC are beneficial for the C=O hydrogenation and C–O cleavage, thereby accelerating the process of hydrodeoxygenation(HDO). Besides, a kinetic model for the HDO of HMF to DMF process has been established based on the experimental results, which elucidated a significant correlation between the measured and the predicted data(R^(2)> 0.97). Corresponding to the adsorption configuration of Ni/WC and substrate determined by in-situ FTIR characterization, this study provides a novel insight into the selective conversion of HMF process for functional biofuel and bio-chemicals.展开更多
The utilization of nickel-based catalysts as alternatives to expensive platinum-based(Pt-based)materials for the hydrogen evolution reaction in acidic electrolytes has attracted considerable attention due to their pot...The utilization of nickel-based catalysts as alternatives to expensive platinum-based(Pt-based)materials for the hydrogen evolution reaction in acidic electrolytes has attracted considerable attention due to their potential for enabling cost-effective industrial applications.However,the unsatisfied cyclic stability and electrochemical activity limit their further application.In this work,nickel-molybdenum(Ni-Mo)alloy catalysts were successfully synthesized through a comprehensive process including electrodeposition,thermal annealing,and electrochemical activation.Owing to the synergistic interaction of molybdenum trinickelide(Ni_(3)Mo)and molybdenum dioxide(MoO_(2))in Ni-Mo alloy,the catalyst display superior overall electrochemical properties.A low overpotential of 86 mV at 10 mA/cm^(2)and a Tafel slope of 74.0 mV/dec in 0.5 mol/L H_(2)SO_(4)solution can be achieved.Notably,remarkable stability with negligible performance degradation even after 100 h could be maintained.This work presents a novel and effective strategy for the design and fabrication of high-performance,non-precious metal electrocatalysts for acidic water electrolysis.展开更多
n-octylphosphonic acid(OPA)was introduced as a novel collector for ilmenite flotation and its effectiveness was compared with the conventional chelating collector,benzohydroxamic acid(BHA).Micro-flotation tests demons...n-octylphosphonic acid(OPA)was introduced as a novel collector for ilmenite flotation and its effectiveness was compared with the conventional chelating collector,benzohydroxamic acid(BHA).Micro-flotation tests demonstrated that OPA was a highly effective and selective collector for separating ilmenite from titanaugite over acidic conditions(optimal pH around 3),which was also supported by adsorption amount measurements.X-ray photoelectron spectroscopy(XPS)tests indicated that the chemisorption of OPA onto ilmenite surface was much stronger than that of BHA.Solution chemistry diagram analyses indicated that OPA could dissociate well at pH 3.0 and mostly exist in anion form.DFT calculations further confirmed that OPA was much easier to adsorb onto ilmenite surface with shorter bond length and lower adsorption energy in comparison with BHA.Therefore,OPA maintained good collecting ability and selectivity for ilmenite flotation in the strongly acidic pulp,providing valuable insights into new collector design and development.展开更多
The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct ...The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.展开更多
Rapid analysis of metal ions and organic compounds in strong acidic solutions is of sustainable interest in multiple disciplines.However,complicated and time-consuming pretreatments are always required for MS analysis...Rapid analysis of metal ions and organic compounds in strong acidic solutions is of sustainable interest in multiple disciplines.However,complicated and time-consuming pretreatments are always required for MS analysis of the compounds in strong acidic solutions.Otherwise,it will result in a weak signal and cause serious damage to the mass spectrometer.Herein,a simple method inherited from nano-ESI MS was developed for rapid analysis of strong acidic solutions.Nanoliter(nL)strong acidic solution was first loaded in the nano-ESI emitter,followed by evaporation to remove the H+and leave the analytes on the wall of the nano-ESI emitter.The evaporation process can be completed within 1 min because of the extremely tiny volume(≤1 nL)of the loaded solution.Then,the dried analytes on the wall of the nano-ESI emitter were redissolved by loading a new solvent,followed by nano-ESI MS analysis.By using this method,metal ions and organic compounds in the strong acidic solution can be detected with low sample consumption(1 nL),high speed(<2 min/sample),high sensitivity(limit of detection=0.2µg/L),and high accuracy(>90%).Proof-of-concept applications of the present method have been successfully achieved for the analysis of gastric juice(pH of the sample=1),monitoring reaction catalyzed by strong acid(pH of the system=0),and micro-area analysis of ores(pH of the extraction solvent=0),showing great application potential in multiple fields.展开更多
基金supported by the earmarked fund for the Modern Agro-Industry Technology Research System (No.CARS-19)the Innovative Research Team in Chinese Academy of Agricultural Sciences (No.CAAS ASTIP-2014-TRICAAS).
文摘Pyrrolizidine alkaloids(PAs)and their N-oxides(PANOs)are phytotoxins produced by various plant species and have been emerged as environmental pollutants.The sorption/desorption behaviors of PAs/PANOs in soil are crucial due to the horizontal transfer of these natural products from PA-producing plants to soil and subsequently absorbed by plant roots.This study firstly investigated the sorption/desorption behaviors of PAs/PANOs in tea plantation soils with distinct characteristics.Sorption amounts for seneciphylline(Sp)and seneciphylline-N-oxide(SpNO)in three acidic soils ranged from 2.9 to 5.9μg/g and 1.7 to 2.8μg/g,respectively.Desorption percentages for Sp and SpNO were from 22.2%to 30.5%and 36.1%to 43.9%.In the mixed PAs/PANOs systems,stronger sorption of PAs over PANOs was occurred in tested soils.Additionally,the Freundlich models more precisely described the sorption/desorption isotherms.Cation exchange capacity,sand content and total nitrogen were identified as major influencing factors by linear regression models.Overall,the soils exhibiting higher sorption capacities for compounds with greater hydrophobicity.PANOs were more likely to migrate within soils and be absorbed by tea plants.It contributes to the understanding of environmental fate of PAs/PANOs in tea plantations and provides basic data and clues for the development of PAs/PANOs reduction technology.
基金financial support from the National Natural Science Foundation of China(22478278,22308246)the Central Government Guides the Local Science and Technology Development Special Fund(YDZJSX20231A015)the Fundamental Research Program of Shanxi Province(202203021212266)。
文摘Ruthenium dioxide(RuO_(2))is one of the most promising acidic oxygen evolution reaction(OER)catalysts to replace the expensive and prevalent iridium(Ir)-based materials.However,the lattice oxygen oxidation induced Ru dissolution during OER compromises the activity and stability.Amorphous materials have been identified as a viable strategy to promote the stability of RuO_(2)in acidic OER applications.This study reported a nanoporous amorphous-rich RuMnO_(x)(A-RuMnO_(x))aerogel for efficient and stable acidic OER.Compared with highly crystalline RuMnO_(x),the weakened Ru–O covalency of A-RuMnO_(x)by forming amorphous structure is favorable to inhibiting the oxidation of lattice oxygen.Meanwhile,this also optimizes the electronic structure of Ru sites from overoxidation and reduces the reaction energy barrier of the rate-determining step.As a result,A-RuMnO_(x)aerogel exhibits an ultra-low overpotential of 145 mV at 10 mA cm^(-2)and durability exceeding 100 h,as well as high mass activity up to 153 mA mg^(-1)_(Ru)at 1.5 V vs.reversible hydrogen electrode(RHE).This work provides valuable guidance for preparing highly active and stable Ru-based catalysts for acidic OER.
基金supported by the Key Projects of Intergovernmental International Cooperation in the Key R&D programs of the Ministry of Science and Technology of China(No.2021YFE0115800)the National Science Funding Committee of China(No.U20A20250)+1 种基金the Programs of the Science and Technology of Yulin City(No.CXY-2023-ZX04)the funding support from Shccig-Qinling Program.
文摘Solving the problem of aggregation and nonuniform dispersion of platinum(Pt)nanoparticles(NPs)is the key to obtaining high catalytic activity.Graphene aerogels(GAs)with large accessible specific surface area and abundant surface defects are considered to be excellent substrate materials for reducing Pt agglomeration and enhancing catalytic activity.Herein,Pt-based GA composites(Pt-GA-x)featuring homogeneous particle dispersion and high activity were successfully synthesized through a one-step reduction method.Fourier transform infrared(FTIR),Raman,and X-ray photoelectron spectroscopy(XPS)test results indicate that the presence of a large number of oxygen-containing functionalities in GA for anchoring Pt NPs,and the interaction with GA produces electronically structured Pt and defect-rich GA substrates.The obtained electrocatalyst Pt-GA-2 possesses a large specific surface area(443.46 m^(2)·g^(−1)),low Pt loading(3.08 wt%),and uniformly dispersed Pt NPs(average 42 nm).As an advanced hydrogen evolution reaction(HER)electrocatalyst,an overpotential of 34 mV is achieved at a current density of 10 mA·cm^(−2)in 0.5 M H_(2)SO_(4)electrolyte,together with a low Tafel slope of 33.2 mV·dec^(−1).Hence,high mass activity(5623 mA·mgPt^(−1))and turnover frequency(TOF=2.57 s^(−1)at η=100 mV)can be obtained,which are 6.81 and 6.76 times higher than those of commercial Pt/C catalysts.All these are attributed to enormous surface defects over GA and electron enrichment on Pt NPs.The present study highlights the unique advantages of GA in electrochemical energy conversion and provides new avenues to fabricate advanced HER electrocatalysts.
基金supported by the National Key Research and Development Program of China(No.2019YFC1803501)the National Natural Science Foundation of China(No.52074357)+2 种基金the Natural Science Foundation of Hunan Province,China(No.2022JJ30713)the Vanadium Titanium Union Foundationthe Project of Technology Innovation Center for Comprehensive Utilization of Strategic Mineral Resources,Ministry of Natural Resources,China。
文摘The potential of 2-amino-1-propanol(AP)as a novel depressant in selectively floating ilmenite from titanaugite under weakly acidic conditions was investigated.Micro-flotation results show that AP significantly reduces the recovery of titanaugite while having no evident impact on ilmenite flotation.Subsequent bench-scale flotation tests further confirm a remarkable improvement in separation efficiency upon the introduction of AP.Contact angle and adsorption tests reveal a stronger affinity of AP towards the titanaugite surface in comparison to ilmenite.Zeta potential measurements and X-ray photoelectron spectroscopy(XPS)analyses exhibit favorable adsorption characteristics of AP on titanaugite,resulting from a synergy of electrostatic attraction and chemical interaction.In contrast,electrostatic repulsion hinders any significant interaction between AP and the ilmenite surface.These findings highlight the potential of AP as a highly efficient depressant for ilmenite flotation,paving the way for reduced reliance on sulfuric acid in the industry.
基金financial support of the Scientific Research Funds of Huaqiao University (605-50Y17073)
文摘The effects of the structure and concentration of impurities on the alkylation of naphthalene with 1-octene catalyzed by chloroaluminate ionic liquid(IL)were investigated.The presence of impurities containing oxygen and nitrogen led to a decrease in the catalytic performance of chloroaluminate IL.As the water concentration increased to 65 mg·g^(-1),the total selectivity of multi-octylnaphthalene gradually decreased to 42.33%,and the average friction coefficient of the multi-octylnaphthalene base oil gradually increased to 0.201.When the concentration of impurities increased to a critical value,the chloroaluminate IL began to deactivate,leading to a decrease in naphthalene conversion.The critical concentrations for ethanolamine,water,methanol,ether,and diisopentyl sulfide were 33 mg·g^(-1),65 mg·g^(-1),67mg·g^(-1),87 mg·g^(-1),and 123 mg·g^(-1),respectively.Impurities with higher basicity resulted in an earlier onset of chloroaluminate IL deactivation.The changes of Lewis and Brønsted acids in chloroaluminate IL under the influence of impurities were investigated using in situ IR and 27Al NMR spectroscopy.2,6-dimethylpyridine as an indicator could detect the changes of Brønsted acid in chloroaluminate IL better,but the changes of Lewis acid were not obvious because of the overlap between the characteristic peaks.2,6-dichloropyridine as an indicator could exclusively detect the changes of Lewis acid in chloroaluminate IL.With the increase inwater concentration,the Lewis acid in chloroaluminate IL was continuously consumed and converted into Brønsted acid,and the Lewis acid gradually decreased,while the Brønsted acid showed a change of increasing first and then decreasing.
基金supported by the National Natural Science Foundation of China(52302039,52301043)the Guangdong Basic and Applied Basic Research Foundation(2022A1515110676)+2 种基金the Shenzhen Science and Technology Program(JCYJ20220531095404009,RCBS20221008093057027,GXWD20231129113217001)the Postdoctoral Research Startup Expenses of Shenzhen(NA25501001)the Shenzhen Introduce High-Level Talents and Scientific Research Start-up Founds(NA11409005)。
文摘Graphene encapsulation has been shown to be an effective technique for improving the corrosion resistance of non-noble metal catalysts for the acidic water electrolysis.The key challenge lies in enhancing the electrocatalytic activity of graphene-encapsulated metals while maintaining their durability in acidic media.Herein,an electron-transfer-tuning strategy is investigated at the graphene/NiMo interface,aiming to improve the hydrogen evolution reaction(HER)performance of graphene-encapsulated NiMo catalysts.The doping of Ti,a low electronegativity element,into NiMo substrate was confirmed to increase electron transfer from the metal core toward the graphene.The electron-rich state on graphene facilitates the adsorption of positively charged protons on graphene,thereby enabling a Pt/C-comparable performance in 0.5 M H_(2)SO_(4),with only a 3.8%degradation in performance over a 120-h continuous test.The proton exchange membrane(PEM)water electrolyzer assembled by the N-doped grapheneencapsulated Ti-doped NiMo exhibits a smaller cell voltage to achieve a current density of 2.0 A cm^(-2),in comparison to the Pt/C based counterpart.This study proposes a novel electron-transfer-tuning strategy to improve the HER activity of graphene-encapsulated non-noble metal catalysts without sacrificing durability in acidic electrolytes.
基金supported by Henan Province Science and Technology Research Project(Grant No.242103810058)Natural Science Foundation of Henan(Grant No.252300421104)+3 种基金National Natural Science Foundation of China(Grant No.52102346)Henan Key Research and Development Project(Grant No.231111230100)Heluo Youth Talent Project(Grant No.2024HLTJ14)Henan Postdoctoral Research Initiation Project(Grant No.HN2022040 and HN2022048).
文摘Proton exchange membrane water electrolyzer(PEMWE)is crucial for the storage and conversion of renewable energy.However,the harsh anode environment and the oxygen evolution reaction(OER),which involves a four-electron transfer,result in a significant overpotential that limits the overall efficiency of hydrogen production.Identifying active sites in the OER is crucial for understanding the reaction mechanism and guiding the development of novel electrocatalysts with high activity,cost-effectiveness,and durability.Herein,we summarize the widely accepted OER mechanism in acidic media,in situ characterization and monitoring of active sites during the reaction,and provide a general understanding of the active sites on various catalysts in the OER,including Ir-based metals,Ir-based oxides,carbon/oxide-supported Ir,Ir-based perovskite oxides,and Ir-based pyrochlore oxides.For each type of electrocatalysts,reaction pathways and actual active sites are proposed based on in situ characterization techniques and theoretical calculations.Finally,the challenges and strategic research directions associated with the design of highly efficient Ir-based electrocatalysts are discussed,offering new insights for the further scientific advancement and practical application of acidic OER.
基金supported by the Young Scientist Funding(22409158,D.R.)from the National Natural Science Foundation of China。
文摘The increasing level of atmospheric carbon dioxide(CO_(2))caused by intensified human activities has exacerbated the greenhouse effect,calling for the technology of CO_(2)fixation.Among the proposed technologies,electrocatalytic CO_(2)reduction in acidic electrolytes has garnered significant attention for its potential in sustainable carbon utilization and renewable energy storage.This review provides a summary of recent advancements in acidic CO_(2)reduction,with a focus on catalyst design strategies,the optimization of the local reaction environment,and the effect of cations.We first evaluated the performance and discussed the challenges for acidic CO_(2)reduction in H-type cells,flow cells,and membrane electrode assembly.Afterward,we highlight the innovative strategies for promoting CO_(2)reduction through optimizing the intrinsic activity and regulating the local environment of catalysts.The critical role of cations in enhancing CO_(2)reduction selectivity is also discussed.The review concludes with an outlook on future research directions,especially the need for the design of catalysts and systems that are stable,scalable,and highly efficient.
文摘Direct converting carbon dioxide(CO_(2))and propane(C_(3)H_(8))into aromatics with high carbon utilization offers a desirable opportunity to simultaneously mitigate CO_(2)emission and adequately utilize C_(3)H_(8) in shale gas.Owing to their thermodynamic resistance,converting CO_(2)and C_(3)H_(8) respectively remains difficult.Here,we achieve 60.2%aromatics selectivity and 48.8%propane conversion over H-ZSM-5-25 via a zeolite-catalyzing the coupling of CO_(2)and C_(3)H_(8).Operando dual-beam FTIR spectroscopy combined with ^(13)C-labeled CO_(2)tracing experiments revealed that CO_(2)is directly involved in the generation of aromatics,with its carbon atoms selectively embedded into the aromatic ring,bypassing the reverse water-gas shift pathway.Accordingly,a cooperative aromatization mechanism is proposed.Thereinto,lactones,produced from CO_(2)and olefins,are proven to be the key intermediate.This work not only provides an opportunity for simultaneous conversion of CO_(2)and C_(3)H_(8),but also expends coupling strategy designing of CO_(2)and alkanes over acidic zeolites.
基金financially supported by the National Natu-ral Science Foundation of China(Nos.21805052 and 22227804)the Guangdong Basic and Applied Basic Research Foundation(No.2023B1515020110)+4 种基金the Science and Technology Research Project of Guangzhou(Nos.202102020787 and 2023A03J0030)the De-partment of Science&Technology of Guangdong Province(No.2022A156)the Key Laboratory of Optoelectronic Materials and Sensors in Guangdong Provincial Universities(No.2023KSYS008)the Key Discipline of Materials Science and Engineering,Bureau of Education of Guangzhou(No.20225546)the College Student Innovation and Entrepreneurship Training Program of Guangzhou University(No.XJ202311078029).
文摘Selective electrocatalysis of two-electron oxygen reduction reaction(2e^(-)ORR)has been recognized as a sustainable and on-site process for hydrogen peroxide(H_(2)O_(2))production.Great progress has been achieved for 2e^(-)ORR in alkaline media.However,it is challenged by insufficient activity and selectiv-ity of the catalysts in acidic electrolytes.Herein,we report sulfur-poisoned PtNi/C catalysts(PtNiSx/C)that could regulate ORR from the 4e^(-)to 2e^(-)pathway.The identified PtNiS0.6/C offers high activity in terms of onset potential of∼0.69 V(vs.RHE)and∼80%selectivity.The mass activity is also compara-ble and outperforms representative Pt-based precious and transition-metal-based catalysts.In addition,it is interestingly found that the Faradaic efficiency further increased to 95%during the long-term elec-trolysis test due to Ni atom surface migration.The electrochemical production of the H_(2)O_(2)system was applied to the electro-Fenton process,which has realized the effective degradation of organic pollutants.This work offers a strategy by sulfur poisoning PtNi/C catalyst to realize Pt-based 2e^(-)ORR active catalysts to electrolysis of H_(2)O_(2)in acidic media.
基金Supported by Faculty Research Grant from Yonsei University College of Medicine,No.6-2017-0155.
文摘BACKGROUND Pancreatic cancer tissues mainly consist of fibrotic and dense stroma,which limits their therapeutic efficacy.The stromal fibroblasts of pancreatic tumors frequently express the secreted protein acidic and rich in cysteine(SPARC).AIM To assess the impact of SPARC and its oncological relevance in patients undergoing pancreatic cancer resection.METHODS Ninety-one pancreatic ductal adenocarcinoma specimens were obtained from patients with curative resection between January 2009 and December 2015 as a retrospective study.SPARC expression patterns were analyzed using immunohistochemistry.Oncological outcomes were analyzed based on SPARC expression patterns.Oncological outcomes,based on SPARC expression,were analyzed in The Cancer Genome Atlas-Pancreatic Adenocarcinoma cohort(retrieved from a public database).RESULTS Patients with stromal SPARC expression(sSPARC+)had poorer overall survival than that in those without it(sSPARC-)(P=0.035).However,among patients who received adjuvant treatment,no difference was observed in survival between the sSPARC+and the sSPARC-groups(P=0.14).In The Cancer Genome Atlas-Pancreatic Adenocarcinoma samples,the high SPARC expression group exhibited noticeably lower overall survival than that in the low expression group(cutoff:14.1295,P=0.0222).Furthermore,SPARC expression was strongly correlated with the percentage the CD10+stromal component(R2=0.804,P<0.001).CONCLUSION Adjuvant chemotherapy improves survivals in sSPARC+pancreatic cancer patients,indicating suggesting sSPARC expression as a prognostic biomarker and potential indicator for neoadjuvant treatment planning.
基金supported by the National Natural Science Foundation of China(52301259 and 22208019)the Research Fund Program for Young Scholars of Beijing Institute of Technology。
文摘Electrochemical carbon dioxide reduction reaction(CO_(2)RR)converts CO_(2) into valuable chemicals by consuming renewable electricity at mild conditions,making it a promising approach to achieving carbon neutrality.However,the reaction of CO_(2) with hydroxide ions to form carbonates leads to low carbon utilization and energy efficiency in near-neutral or alkaline CO_(2)RR.The high concentration of protons in acidic media can effectively mitigate carbonate formation and deposition,thereby significantly minimizing carbon loss and energy consumption.Unfortunately,hydrogen evolution reaction(HER)is more kinetically favorable than CO_(2)RR in acidic media.Herein,we comprehensively overview recent progress in acidic CO_(2)RR and propose two strategies derived from the competing reaction pathways of HER and CO_(2)RR:one focuses on regulating the H+mass transport,while the other aims to modulate the intrinsic kinetic activity of CO_(2)RR.The two strategies are designed to compete for the limited active sites on the catalyst surface,inhibit side reactions,and enhance the activity and selectivity of CO_(2)RR.The representative approaches include modulating the interface electric field,constructing a local alkaline environment,and regulating competing adsorption sites.Finally,we also review the technical challenges and future perspectives of acidic CO_(2)RR coupled with membrane electrode assemblies(MEAs).
基金Supported by the Natural Science Foundation of Jiangxi Province,No.20242BAB25489National Natural Science Foundation of China,No.82260211 and No.81460092+1 种基金Key Research and Development Project in Jiangxi Province,No.20203BBG73058Chinese Medicine Science and Technology Project in Jiangxi Province,No.2020A0166。
文摘BACKGROUND Diabetic retinopathy(DR)is the leading cause of vision loss in patients with diabetes.The vascular endothelial growth factor(VEGF)pathway plays a critical role in the pathogenesis of DR,and ranibizumab,an anti-VEGF agent,has shown promise in its treatment.Signal transducer and activator of transcription 3(STAT3)is involved in inflammatory processes and cellular signaling,while glial fibrillary acidic protein(GFAP)is a marker of glial cell activation,both contributing to retinal damage in DR.However,the mechanisms by which ranibizumab affect early-stage DR through the VEGF/STAT3/GFAP pathway are not fully understood.AIM To investigate the role of ranibizumab in early DR via the VEGF/STAT3/GFAP pathway.METHODS Adult retinal pigment epithelial 19(ARPE-19)cells and human retinal microvascular endothelial cells(HRMECs)were cultured under high-glucose conditions to simulate a diabetic environment.The effects of ranibizumab on cytokine mRNA and protein expression were analyzed by quantitative polymerase chain reaction and Western blot analysis.A diabetic rat model was induced with streptozotocin(60 mg/kg).Retinal changes,including retinal ganglion cell(RGC)apoptosis,vascular alterations,and cytokine expression,were evaluated using fundus fluorescein angiography,hematoxylin and eosin and periodic acid Schiff staining,immunofluorescence,confocal imaging,and Western blot analysis.RESULTS High-glucose conditions significantly increased the mRNA and protein levels of VEGF,STAT3,GFAP,and other cytokines in ARPE-19 and HRMECs.However,these levels were partially suppressed by ranibizumab.RGC apoptosis,vascular leakage,and elevated cytokine expression were observed during early-stage DR in diabetic rats.Ranibizumab treatment in diabetic rats reduced cytokine expression,restored RGCs,and repaired vascular networks.CONCLUSION Intravitreal ranibizumab modulates the VEGF/STAT3/GFAP pathway,suppresses cytokine expression,and promotes retinal repair,effectively delaying or preventing early DR progression.
基金supported by the Natural Science Foundation of Shandong Province ZR2024MB087the National Natural Science Foundation of China(No.52122308,51973200,52202050,and 21905253)+3 种基金the Natural Science Foundation of Henan(202300410372)the Joint Fund of Science and Technology R&D Plan of Henan Province(232301420042)the China Postdoctoral Science Foundation(2022TQ0286)the Center for Modern Analysis and Gene Sequencing of Zhengzhou University for supporting this project。
文摘The development of highly active and stable bifunctional electrocatalysts in acidic media is crucial to hydrogen production by proton exchange membrane.In this study,we designed a RuO_(2)-IrO_(2)heterostructure catalyst coupled by carbon quantum dots(CQDs).The catalyst showed excellent electrocatalytic performance for water splitting under acidic conditions.The overpotentials of oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)were as low as 180 and 15 mV at 10 mA/cm^(2)in 0.5 M H_(2)SO_(4),respectively.The acid electrolytic cell developed with RuO_(2)-IrO_(2)@CQDs as anode and cathode operated stably at 10 m A/cm^(2)for 120 h.In situ measurements and theoretical calculation reveal that the unique lattice oxygen mechanism path of RuO_(2)-IrO_(2)@CQDs can bypass the OOH^(*)intermediate and breaks the linear relationship of adsorbent evolution mechanism path,resulting in higher OER catalytic activity.
基金supported by Young Project of Education Department in Guizhou Province(No.2022099)the Natural Science Special of Guizhou University(No.X202220 Special Post A)the National Natural Science Foundation of China(Grant No.22208071)。
文摘The persistent stability of ruthenium dioxide(RuO_(2))in acidic oxygen evolution reactions(OER)is compromised by the involvement of lattice oxygen(LO)and metal dissolution during the OER process.Heteroatom doping has been recognized as a viable strategy to foster the stability of RuO_(2)for acidic OER applications.This study presented an ion that does not readily gain or lose electrons,Ba^(2+),into RuO_(2)(Ba-RuO_(2))nanosheet(NS)catalyst that increased the number of exposed active sites,achieving a current density of 10 mA/cm^(2)with an overpotential of only 229 mV and sustaining this output for over 250 h.According to density functional theory(DFT)and X-ray absorption spectroscopy,Ba doping resulted in a longer Ru-O bond length,which in turn diminished the covalency of the bond.This alteration curtailed the involvement of LO and the dissolution of ruthenium(Ru),thereby markedly improving the durability of the catalyst over extended periods.Additionally,attenuated total reflectance-surface enhanced infrared absorption spectroscopy analysis substantiated that the OER mechanism shifted from a LO-mediated pathway to an adsorbate evolution pathway due to Ba doping,thereby circumventing Ru over-oxidation and further enhancing the stability of RuO_(2).Furthermore,DFT findings uncovered that Ba doping optimizes the adsorption energy of intermediates,thus enhancing the OER activity in acidic environments.This study offers a potent strategy to guide future developments on Ru-based oxide catalysts'stability in an acidic environment.
基金Fundamental Research Foundation of CAF (CAFYBB2022QB001)National Nature Science Foundation of China for Excellent Young Scientists Fund (32222058)。
文摘The high-efficiency conversion of biomass resources to biofuels has attracted widespread attention, and the active sites and synergistic effect of catalysts significantly impact their surface arrangement and electronic structure. Here, a nickel-based transition metal carbide catalyst(Ni/TMC) with high Lewis acidity was prepared by self-assembly of transition metal carbide(TMC) and nickel, which exhibited excellent performance on synergistic hydrogenation and hydrogenolysis of 5-hydroxymethylfurfural(HMF) into liquid biofuel 2,5-dimethylfuran(DMF).Notably, Ni/WC with the highest Lewis acidity(4728.3 μmol g^(-1)) can achieve 100% conversion of HMF to 97.6% yield of DMF, with a turnover frequency of up to 46.5 h^(-1). The characterization results demonstrate that the rich Lewis acid sites yielded by the synergistic effect between Ni species and TMC are beneficial for the C=O hydrogenation and C–O cleavage, thereby accelerating the process of hydrodeoxygenation(HDO). Besides, a kinetic model for the HDO of HMF to DMF process has been established based on the experimental results, which elucidated a significant correlation between the measured and the predicted data(R^(2)> 0.97). Corresponding to the adsorption configuration of Ni/WC and substrate determined by in-situ FTIR characterization, this study provides a novel insight into the selective conversion of HMF process for functional biofuel and bio-chemicals.
基金supported by the National Natural Science Foundation of China(22179138).
文摘The utilization of nickel-based catalysts as alternatives to expensive platinum-based(Pt-based)materials for the hydrogen evolution reaction in acidic electrolytes has attracted considerable attention due to their potential for enabling cost-effective industrial applications.However,the unsatisfied cyclic stability and electrochemical activity limit their further application.In this work,nickel-molybdenum(Ni-Mo)alloy catalysts were successfully synthesized through a comprehensive process including electrodeposition,thermal annealing,and electrochemical activation.Owing to the synergistic interaction of molybdenum trinickelide(Ni_(3)Mo)and molybdenum dioxide(MoO_(2))in Ni-Mo alloy,the catalyst display superior overall electrochemical properties.A low overpotential of 86 mV at 10 mA/cm^(2)and a Tafel slope of 74.0 mV/dec in 0.5 mol/L H_(2)SO_(4)solution can be achieved.Notably,remarkable stability with negligible performance degradation even after 100 h could be maintained.This work presents a novel and effective strategy for the design and fabrication of high-performance,non-precious metal electrocatalysts for acidic water electrolysis.
基金supported by the National Natural Science Foundation of China(No.52074357)the Vanadium Titanium Union Foundation,ChinaChina Postdoctoral Science Foundation(No.2019M650188)。
文摘n-octylphosphonic acid(OPA)was introduced as a novel collector for ilmenite flotation and its effectiveness was compared with the conventional chelating collector,benzohydroxamic acid(BHA).Micro-flotation tests demonstrated that OPA was a highly effective and selective collector for separating ilmenite from titanaugite over acidic conditions(optimal pH around 3),which was also supported by adsorption amount measurements.X-ray photoelectron spectroscopy(XPS)tests indicated that the chemisorption of OPA onto ilmenite surface was much stronger than that of BHA.Solution chemistry diagram analyses indicated that OPA could dissociate well at pH 3.0 and mostly exist in anion form.DFT calculations further confirmed that OPA was much easier to adsorb onto ilmenite surface with shorter bond length and lower adsorption energy in comparison with BHA.Therefore,OPA maintained good collecting ability and selectivity for ilmenite flotation in the strongly acidic pulp,providing valuable insights into new collector design and development.
基金supported by the Taishan Scholar Program of Shandong Province,China(tsqn202211162)the National Natural Science Foundation of China(22102079)the Natural Science Foundation of Shandong Province of China(ZR2021YQ10,ZR2022QB163)。
文摘The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.
基金supported by the National Natural Science Foundation of China(Nos.21864001,21727812 and 21765001)the Ph.D.Start-up Foundation of East China University of Technology(No.DHBK2020001).
文摘Rapid analysis of metal ions and organic compounds in strong acidic solutions is of sustainable interest in multiple disciplines.However,complicated and time-consuming pretreatments are always required for MS analysis of the compounds in strong acidic solutions.Otherwise,it will result in a weak signal and cause serious damage to the mass spectrometer.Herein,a simple method inherited from nano-ESI MS was developed for rapid analysis of strong acidic solutions.Nanoliter(nL)strong acidic solution was first loaded in the nano-ESI emitter,followed by evaporation to remove the H+and leave the analytes on the wall of the nano-ESI emitter.The evaporation process can be completed within 1 min because of the extremely tiny volume(≤1 nL)of the loaded solution.Then,the dried analytes on the wall of the nano-ESI emitter were redissolved by loading a new solvent,followed by nano-ESI MS analysis.By using this method,metal ions and organic compounds in the strong acidic solution can be detected with low sample consumption(1 nL),high speed(<2 min/sample),high sensitivity(limit of detection=0.2µg/L),and high accuracy(>90%).Proof-of-concept applications of the present method have been successfully achieved for the analysis of gastric juice(pH of the sample=1),monitoring reaction catalyzed by strong acid(pH of the system=0),and micro-area analysis of ores(pH of the extraction solvent=0),showing great application potential in multiple fields.
