Iridium(Ir)-based catalysts are highly efficient for the anodic oxygen evolution reaction(OER)due to high stability and anti-corrosion ability in the strong acid electrolyte.Recently,intensive attention has been direc...Iridium(Ir)-based catalysts are highly efficient for the anodic oxygen evolution reaction(OER)due to high stability and anti-corrosion ability in the strong acid electrolyte.Recently,intensive attention has been directed to novel,efficient,and low-cost Ir-based catalysts to overcome the challenges of their application in the water electrolysis technique.To make a comprehensive understanding of the recently developed Ir-based catalysts and their catalytic properties,the mechanism and catalytic promotion principles of Ir-based catalysts were discussed for OER in the acid condition aimed for the proton exchange membrane water electrolyzer(PEMWE)in this review.The OER catalytic mechanisms of the adsorbate evolution mechanism and the lattice oxygen mechanism were first presented and discussed for easy understanding of the catalytic mechanism;a brief perspective analysis of promotion principles from the aspects of geometric effect,electronic effect,synergistic effect,defect engineering,support effect was concluded.Then,the latest progress and the practical application of Ir-based catalysts were introduced in detail,which was classified into the varied composition of Ir catalyst in terms of alloys,hetero-element doping,perovskite,pyrochlore,heterostructure,core-shell structure,and supported catalysts.Finally,the problems and challenges faced by the current Ir-based catalyst in the acidic electrolyte were put forward.It is concluded that highly efficient catalysts with low Ir loading should be developed in the future,and attention should be paid to probing the structural and performance correlation,and their application in real PEMWE devices.Hopefully,the current effort can be helpful in the catalysis mechanism understanding of Ir-based catalysts for OER,and instructive to the novel efficient catalysts design and fabrication.展开更多
Sediment properties have a crucial effect on the growth and recovery of aquatic plants in lakes.Addition of various chemical substances has been proposed to reinforce the recovery of plants after a nutrient loading re...Sediment properties have a crucial effect on the growth and recovery of aquatic plants in lakes.Addition of various chemical substances has been proposed to reinforce the recovery of plants after a nutrient loading reduction.However,the effects of such sediment amendments on plant growth,especially those from rhizosphere microorganisms,is limited.We added Kaolin clay to sediments in different concentrations to explore its impact on the growth of Vallisneria natans and Ottelia acuminate and the concurrent shift in rhizosphere microorganisms using high-throughput sequencing technology.We found that the addition of low doses(10%and 20%in mass ratio)of Kaolin significantly modified sediment conditions(oxidation reduction potential and pH),with implications also for the composition,diversity,and stability of rhizosphere microorganisms.LEfSe analysis revealed that low-dose addition of Kaolin increased the abundances of functional microbial groups that benefit plant nutrient absorption and enhance plant stress resistance,such as Spirillaceae,Rhodocyclaceae,and Burkholderiales.Moreover,low doses of Kaolin significantly promoted the photosynthesis and nutrient absorption of submerged macrophytes,thereby facilitating plant growth.A structural equation model(SEM)indicated that the direct impact of Kaolin on the growth of submerged plants was relatively minor,while the indirect effect through modulation of rhizosphere microorganisms was important.Our study suggests that low doses of Kaolin may be used to promote the growth of submerged macrophytes when lakes with a high organic content in the sediment are recovering after nutrient loading reduction.展开更多
Fe_2O_3 nanorods and hexagonal nanoplates were synthesized and used as the promoters for Pt electrocatalysts toward the methanol oxidation reaction（MOR） in an alkaline electrolyte.The catalysts were characterized by...Fe_2O_3 nanorods and hexagonal nanoplates were synthesized and used as the promoters for Pt electrocatalysts toward the methanol oxidation reaction（MOR） in an alkaline electrolyte.The catalysts were characterized by scanning electron microscopy,transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,cyclic voltammetry and chronoamperometry.The results show that the presence of Fe_2O_3 in the electrocatalysts can promote the kinetic processes of MOR on Pt,and this promoting effect is related to the morphology of the Fe_2O_3 promoter.The catalyst with Fe_2O_3 nanorods as the promoter（Pt-Fe_2O_3/C-R） exhibits much higher catalytic activity and stability than that with Fe_2O_3 nanoplates as the promoter（Pt-Fe_2O_3/C-P）.The mass activity and specific activity of Pt in a Pt-Fe_2O_3/C-R catalyst are 5.32 A/mgpt and 162.7 A/m^2_（Pt）,respectively,which are approximately 1.67 and 2.04 times those of the Pt-Fe_2O_3/C-P catalyst,and 4.19 and 6.16 times those of a commercial PtRu/C catalyst,respectively.Synergistic effects between Fe_2O_3 and Pt and the high content of Pt oxides in the catalysts are responsible for the improvement.These findings contribute not only to our understanding of the MOR mechanism but also to the development of advanced electrocatalysts with high catalytic properties for direct methanol fuel cells.展开更多
Pt/Eu2O3-CeO2 materials with different Eu concentrations were prepared and applied to toluene destruction,and the remarkable promotion impact of EuOx on Pt/CeO2 can be observed.The characterization results reveal that...Pt/Eu2O3-CeO2 materials with different Eu concentrations were prepared and applied to toluene destruction,and the remarkable promotion impact of EuOx on Pt/CeO2 can be observed.The characterization results reveal that the presence of EuOx significantly enhances the redox property,lattice O concentration,and Ce3+ ratio of the Pt/CeO2 material,which facilitates the dispersion and activity of Pt active sites and thus accelerates the decomposition process of toluene.Among all catalysts,a sample with an Eu content of 2.5 at.%(Pt/EC-2.5)possesses the best catalytic activity with 0.09 vol% of toluene completely destructed at 200 ℃ under a relatively high GHSV of 50000 h^-1.The possible reaction pathway and mechanism of toluene combustion over Pt/Eu2O3-CeO2 samples are presented according to in-situ DRIFTS,which confirms that the toluene oxidation process obeys the Mars-van Krevelen mechanism with aldehydes and ketones as primary organic intermediates.展开更多
The seeds and sprouts of mung bean are very common cruise in Asia.Evidence showed that bioactive compounds in mung bean have emerged as an increasing scientific interest due to their role in the prevention of degenera...The seeds and sprouts of mung bean are very common cruise in Asia.Evidence showed that bioactive compounds in mung bean have emerged as an increasing scientific interest due to their role in the prevention of degenerative diseases.All data of in vitro,in vivo and clinical studies of mung bean and its impact on human health were collected from a library database and electronic search.Botanical,phytochemical and pharmacological information was gathered and orchestrated.Remarkable studies have been demonstrated,showing the enhancement of metabolites in mung bean during the sprouting process,which possesses various health benefiting bioactive compounds.These compounds have been frequently attributed to their antioxidant,anti-diabetic,antimicrobial,anti-hyperlipidemic and antihypertensive effect,anti-inflammatory,and anticancer,anti-tumor and anti-mutagenic properties.In this critical review,we aimed to study the insight of the nutritional compositions,phytochemistry,and healthpromoting effects of mung bean and its sprouts.The various curative potential of mung bean provides successive preclinical outcomes in the field of drug discovery and this review strongly recommends that mung bean is an excellent nutritive legume,which modulates or prevents chronic degenerative diseases.展开更多
This paper presents how the combustion performance of nano-sized aluminum(nAl)powder in carbon dioxide are affected by silica. The ignition and combustion performance of nAl powder with silica addition were studied by...This paper presents how the combustion performance of nano-sized aluminum(nAl)powder in carbon dioxide are affected by silica. The ignition and combustion performance of nAl powder with silica addition were studied by a high-temperature tube furnace. An s-type thermocouple and a high-speed motion acquisition instrument were performed to evaluate the ignition temperature, maximum combustion temperature, maximum change of rate of temperature, and combustion propagation speed. The combustion efficiency and combustion products were measured and analyzed by a gas-volumetric method and an X-ray diffraction. The results show that silica added into nAl powder can enhance its maximum combustion temperature and maximum change of rate of temperature, while its ignition temperature increases slightly. The nAl powders with addition of 6.00 wt.% and 12.00 wt.% silica present high combustion propagation speeds, especially for the latter, it has high combustion efficiency. The effect mechanism of silica on the combustion of nAl powder in carbon dioxide was discussed.展开更多
The construction of highly active catalysts for methanol oxidation reaction(MOR)is central to direct methanol fuel cells.Tremendous progress has been made in transition metal phosphides(TMPs)based catalysts.However,TM...The construction of highly active catalysts for methanol oxidation reaction(MOR)is central to direct methanol fuel cells.Tremendous progress has been made in transition metal phosphides(TMPs)based catalysts.However,TMPs would be partially damaged and transformed into new substances(e.g.,Pt-M-P composite,where M represents a second transition metal)during Pt deposition process.This would pose a large obstacle to the cognition of the real promoting effects of TMPs in MOR.Herein,Co_(2)P co-catalysts(Pt-P/Co_(2)P@NPC,where NPC stands for N and P co-doped carbon)and Pt-Co-P composite catalysts(Pt-CoP/NPC)were controllably synthesized.Electrocatalysis tests show that the Pt-Co-P/NPC exhibits superior MOR activity as high as 1016 m A/mg_(Pt),significantly exceeding that of Pt-P/Co_(2)P@NPC(345 m A/mg_(Pt)).This result indicates that the promoting effect is ascribed primarily to the resultant Pt-Co-P composite,in sharply contrast to previous viewpoint that Co_(2)P itself improves the activity.Further mechanistic studies reveal that Pt-Co-P/NPC exhibits much stronger electron interaction and thus manifesting a remarkably weaker CO absorption than Pt-P/Co_(2)P@NPC and Pt/C.Moreover,Pt-Co-P is also more capable of producing oxygen-containing adsorbate and thus accelerating the removal of surface-bonded CO^(*),ultimately boosting the MOR performance.展开更多
A significant promotion effect of low-molecular hydroxyl compounds(LMHCs) was found in the nano-photoelectrocatalytic(NPEC) degradation of fulvic acid(FA),which is a typical kind of humic acid existing widely in natur...A significant promotion effect of low-molecular hydroxyl compounds(LMHCs) was found in the nano-photoelectrocatalytic(NPEC) degradation of fulvic acid(FA),which is a typical kind of humic acid existing widely in natural water bodies,and its influence mechanism was proposed.A TiO_2 nanotube arrays(TNAs) material is served as the photoanode.Methanol,ethanediol,and glycerol were chosen as the representative of LMHCs in this study.The adsorption performance of organics on the surface of TNAs was investigated by using the instantaneous photocurrent value.The adsorption constants of FA,methanol,ethanediol,and glycerol were 43.44,19.32,7.00,and 1.30,respectively,which indicates that FA has the strongest adsorption property.The degradation performance of these organics and their mixture were observed in a thin-layer reactor.It shows that FA could hardly achieve exhausted mineralization alone,while LMHCs could be easily oxidized completely in the same condition.The degradation degree of FA,which is added LMHCs,improves significantly and the best promotion effect is achieved by glycerol.The promotion effect of LMHCs in the degradation of FA could be contributed to the formation of a tremendous amount of hydroxyl radicals in the NPEC process.The hydroxyl radicals could facilitate the complete degradation of both FA and its intermediate products.Among the chosen LMHCs,glycerol molecule which has three hydroxyls could generate the most hydroxyl radicals and contribute the best effective promotion.This work provides a new way to promote the NPEC degradation of FA and a direction to remove humus from polluted water.展开更多
Tourmaline can promote the growth of microorganisms under the temperature less than 900 ℃ by experiment. However, this promotion effect will vanish at 900 ℃ as a result of denaturation. Through the XRD analysis the ...Tourmaline can promote the growth of microorganisms under the temperature less than 900 ℃ by experiment. However, this promotion effect will vanish at 900 ℃ as a result of denaturation. Through the XRD analysis the crystal form change can explain the vanishment of tourmaline’s biological promotion effect at high temperature. Therefore, tourmaline as a biological promoter was used to prepare a kind of biological promotive ceramsite with the surface area of 7.914 m2/g, pore volume of 0.1002 mg/L, superficial pH value of 7.8, Zeta potential of 25 mV, unit water absorption of 0.1365 g/g, biocompatibility of 0.023 A/g and SICE of 0.8456. The experimental results show that the biomass of biological promotive ceramsite is 3.58 times more than that of ordinary ceramsite, and the treatment effect of the biological promotive ceramsite is better than the ordinary ceramsite. These features of this new biological promotive ceramsite makes it a preferable biovector.展开更多
A simple strategy of Cu modification was proposed to broaden the operation temperature window for NbCe catalyst.The best catalyst Cu0.010/Nb1Ce3 presented over 90%NO conversion in a wide temperature range of 200-400℃...A simple strategy of Cu modification was proposed to broaden the operation temperature window for NbCe catalyst.The best catalyst Cu0.010/Nb1Ce3 presented over 90%NO conversion in a wide temperature range of 200-400℃and exhibited an excellent H_(2)O or/and SO_(2) resistance at 275℃.To understand the promotional mechanism of Cu modification,the correlation among the"activity-structure-property"were tried to establish systematically.Cu species highly dispersed on NbCe catalyst to serve as the active component.The strong interaction among Cu,Nb and Ce promoted the emergence of NbO4 and induced more Bronsted acid sites.And Cu modification obviously enhanced the redox behavior of the NbCe catalyst.Besides,EPR probed the Cu species exited in the form of monomeric and dimeric Cu^(2+),the isolated Cu^(2+)acted as catalytic active sites to promote the reaction:Cu^(2+)-NO_(3)^(-)+NO(g)→Cu^(2+)-NO_(2)^(-)+NO_(2)(g).Then the generated NO_(2) would accelerate the fast-SCR reaction process and thus facilitated the lowtemperature deNO_(x) efficiency.Moreover,surface nitrates became unstable and easy to decompose after Cu modification,thus providing additional adsorption and activation sites for NH3,and ensuring the improvement of catalytic activity at high temperature.Since the NH3-SCR reaction followed by E-R reaction pathway efficaciously over Cu_(0.010)/Nb_(1)Ce_(3) catalyst,the excellent H_(2)O and SO_(2) resistance was as expected.展开更多
Activated carbon （AC） supported silver catalysts were prepared by incipient wetness impregnation method and their catalytic performance for CO preferential oxidation （PROX） in excess H2 was evaluated. Ag/AC cataly...Activated carbon （AC） supported silver catalysts were prepared by incipient wetness impregnation method and their catalytic performance for CO preferential oxidation （PROX） in excess H2 was evaluated. Ag/AC catalysts, after reduction in H2 at low temperatures （≤200 ℃） following heat treatment in He at 200 ℃ （He200H200）, exhibited the best catalytic properties. Temperature-programmed desorption （TPD）, X-ray diffraction （XRD） and temperature-programmed reduction （TPR） results indicated that silver oxides were produced during heat treatment in He at 200 ℃ which were reduced to metal silver nanoparticles in H2 at low temperatures （≤200 ℃）, simultaneously generating the adsorbed water/OH. CO conversion was enhanced 40% after water treatment following heat treatment in He at 600 ℃. These results imply that the metal silver nanoparticles are the active species and the adsorbed water/OH has noticeable promotion effects on CO oxidation. However, the promotion effect is still limited compared to gold catalysts under the similar conditions, which may be the reason of low selectivity to CO oxidation in PROX over silver catalysts. The reported Ag/AC-S-He catalyst after He200H200 treatment displayed similar PROX of CO reaction properties to Ag/SiO2. This means that Ag/AC catalyst is also an efficient low-temperature CO oxidation catalyst.展开更多
The effects of riboflavin deficiency and simultaneously nitrosodimethylamine (NDMA) given by gastric intubation on the hepatic glutathione (GSH) content were examined in rats. On different days of the experiment, hepa...The effects of riboflavin deficiency and simultaneously nitrosodimethylamine (NDMA) given by gastric intubation on the hepatic glutathione (GSH) content were examined in rats. On different days of the experiment, hepatic GSH content of the riboflavin deficient rats decreased to 55-61% of the control rats. When NDMA was given 6 mg kg by gastric intubation to riboflavin deficient rats, hepatic GSH content decreased markedly to 39-43% of the control rats. After supplying riboflavin, hepatie GSH content of the deficient rats recovered to the level of the control rats. These results suggest that alterations of rat hepatic GSH content during riboflavin deficiency may imply as one of the promoting effects of riboflavin deficiency on the carcinogenesis of nitrosamines.展开更多
Basicity of ZrO2 is enhanced by KF modification due to the reaction of KF with ZrO2 surface: KF+ ZrO2-> K2ZrF6 + KOH. After pretreated above 673K, KF/ZrO2 catalyst exhibited higher activity for 1-butene isomerizati...Basicity of ZrO2 is enhanced by KF modification due to the reaction of KF with ZrO2 surface: KF+ ZrO2-> K2ZrF6 + KOH. After pretreated above 673K, KF/ZrO2 catalyst exhibited higher activity for 1-butene isomerization at 273K than ZrO2. The amount of basic sites strongly adsorbing CO2 in the form of bicarbonate was also increased.展开更多
It was found for the first time that the compounds with only one functional group, such as pyridine, can show the promotion effect for the electrochemical reaction of cytochrome C at gold electrodes.
A Plant Biostimulant is any substance or microorganism applied to plants to enhance nutrition efficiency,abioticstress tolerance,and/or crop quality traits,regardless of its nutrient content.The application of Plant b...A Plant Biostimulant is any substance or microorganism applied to plants to enhance nutrition efficiency,abioticstress tolerance,and/or crop quality traits,regardless of its nutrient content.The application of Plant biostimulants(PBs)in production can reduce the application of traditional pesticides and chemical fertilizers and improvethe quality and yield of crops,which is conducive to the sustainable development of agriculture.An in-depthunderstanding of the mechanism and effect of various PBs is very important for how to apply PBs reasonablyand effectively in the practice of crop production.This paper summarizes the main classification of PBs;Thegrowth promotion mechanism of PBs was analyzed from four aspects:improving soil physical and chemical properties,enhancing crop nutrient absorption capacity,photosynthesis capacity,and abiotic stress tolerance;At thesame time,the effects of PBs application on seed germination,seedling vigor,crop yield,and quality were summarized;Finally,how to continue to explore and study the use and mechanism of PBs in the future is analyzedand prospected,to better guide the application of PBs in crop production in the future.展开更多
A series of K-promoted Pt/Al2O3 catalysts were tested for CO oxidation. It was found that the addition of K significantly enhanced the activity. A detailed kinetic study showed that the activation energies of the K-co...A series of K-promoted Pt/Al2O3 catalysts were tested for CO oxidation. It was found that the addition of K significantly enhanced the activity. A detailed kinetic study showed that the activation energies of the K-containing catalysts were lower than those of the K-free ones, particularly for catalysts with high Pt contents （51.6 k）/mol for 0.42K-2.0Pt/Al2O3 and 6：3.6 kJ/mol for 2.0Pt/Al2O3 ）. The CO reaction orders were higher for the K-containing catalysts （about -0.2） than for the K-free ones （about -0.5）, with the former having much lower equilibrium constants for CO adsorption than the latter. In situ Fourier-transform infrared spectroscopy showed that surface CO desorption from the 0.42K-2.0Pt/Al2O3 catalyst was easier than from 2.0Pt/Al2O3. The promoting effect of K was therefore caused by weakening of the interactions between CO and surface Pt atoms. This decreased coverage of the catalyst with CO and facilitated competitive O2 chemisorption on the Pt surface, and significantly lowered the reaction barrier between chemisorbed CO and O2 species.展开更多
A series of novel carbon nanofibers(CNFs)based Cu-ZrO2 catalysts were synthesized by deposition precipitation method.To investigate the influence of promoter,catalysts were loaded with 1,2,3 and 4 wt%ZnO and character...A series of novel carbon nanofibers(CNFs)based Cu-ZrO2 catalysts were synthesized by deposition precipitation method.To investigate the influence of promoter,catalysts were loaded with 1,2,3 and 4 wt%ZnO and characterized by ICP-OES,HRTEM,BET,N2O chemisorption,TPR,XPS and CO2-TPD techniques.The results revealed that physicochemical properties of the catalysts were strongly influenced by incorporation of ZnO to the parent catalyst.Copper surface area(SCu)and dispersion(DCu)were slightly decreased by incorporation of ZnO promoter.Nevertheless,SCuand DCuwere remarkably decreased when ZnO content was exceeded beyond 3 wt%.The catalytic performance was evaluated by using autoclave slurry reactor at a pressure and temperature of 30 bar and 180℃,respectively.The promotion of CuZrO2/CNFs catalyst with 3 wt%of ZnO enhanced methanol synthesis rate from 32 to 45 g kg^-1 h^-1.Notably,with the ZnO promotion the selectivity to methanol was enhanced to 92%compared to 78%of the un-promoted Cu-ZrO2/CNFs catalyst at the expense of a lowered CO2 conversion.In addition,the catalytic activity of this novel catalyst system for CO2 hydrogenation to methanol was compared with the recent literature data.展开更多
The effect of super absorbent polymer（SAP） on the formation of tetrahydrofuran（THF） hydrate was studied by the successional cooling method.It was found that THF solution samples with 0.004 wt% and 0.03 wt% of SAP ...The effect of super absorbent polymer（SAP） on the formation of tetrahydrofuran（THF） hydrate was studied by the successional cooling method.It was found that THF solution samples with 0.004 wt% and 0.03 wt% of SAP formed THF hydrate completely during the same cooling process.The corresponding induction time was 16-29 min,14-31 min,respectively,which was obviously shorter than that of THF solution samples without SAP（25-62 min）.It indicated that SAP accelerated the formation of THF hydrate.At the same time,the pictures of hydrate formation with and without SAP had been compared.It was found that SAP did not change the morphology of the hydrate.Finally,the mechanism of SAP promoting effect on the formation of THF hydrate was suggested.展开更多
The hydrogenation of petroleum resin(PR)is an effective process to prepare high value-added hydrogenated PR(HPR).However,the preparation of non-noble metal-based catalysts with high catalytic activity for PR hydrogena...The hydrogenation of petroleum resin(PR)is an effective process to prepare high value-added hydrogenated PR(HPR).However,the preparation of non-noble metal-based catalysts with high catalytic activity for PR hydrogenation still remains a challenge.Herein,a La promoted Ni-based catalyst is reported through the thermal reduction of quaternary Ni La Mg Al-layered double hydroxides(Ni La Mg Al-LDHs).The incorporation of La is beneficial to the reduction and stability of Ni particles with reduced particle size,and the increased alkalinity effectively mitigates the breakage of molecular chains of PR.As a result,the La promoted Ni-based catalyst exhibits high catalytic activity and excellent stability for PR hydrogenation.A hydrogenation degree of 95.4%and 96.1%can be achieved for HC_(5)PR and HC_(9) PR with less reduced softening point,respectively.Notably,the hydrogenation degree still maintains at 92.7%even after 100 hours’reaction,much better than that without La incorporation or prepared using conventional impregnation method.展开更多
For the recycling of Pd and Ag from high-level liquid waste(HLLW), the electrochemical behaviors of Pd and Ag in the simulated HNO_(3) solutions were investigated by cyclic voltammetry and potentiostatic deposition.Sc...For the recycling of Pd and Ag from high-level liquid waste(HLLW), the electrochemical behaviors of Pd and Ag in the simulated HNO_(3) solutions were investigated by cyclic voltammetry and potentiostatic deposition.Scanning electron microscopy(SEM) and X-ray diffraction(XRD) were used to-observe the deposits morphology and to evaluate their composition. The results indicate that the formation of NO_(2)^(-)electrodeposited. When Pd and Ag are electrodeposited together, more metals are gained in the same time, and the deposited Ag does not dissolve in this situation. The metals are electrodeposited completely at the potentials from -0.4 to -0.6 V(vs MSE) and the deposits contai-n Ag and PdHx. The electrodeposition of Pd can boost h-ydrogen evolution,and then the reaction between H;and NO_(2)^(-)is sped up, thereby lowering the concentration of NO_(2)^(-)and inhibiting the dissolution of Ag.展开更多
基金This work is supported by the National Natural Science Foundation of China(Nos.21972124 and 22272148),a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institution was also appreciated by the authors.
文摘Iridium(Ir)-based catalysts are highly efficient for the anodic oxygen evolution reaction(OER)due to high stability and anti-corrosion ability in the strong acid electrolyte.Recently,intensive attention has been directed to novel,efficient,and low-cost Ir-based catalysts to overcome the challenges of their application in the water electrolysis technique.To make a comprehensive understanding of the recently developed Ir-based catalysts and their catalytic properties,the mechanism and catalytic promotion principles of Ir-based catalysts were discussed for OER in the acid condition aimed for the proton exchange membrane water electrolyzer(PEMWE)in this review.The OER catalytic mechanisms of the adsorbate evolution mechanism and the lattice oxygen mechanism were first presented and discussed for easy understanding of the catalytic mechanism;a brief perspective analysis of promotion principles from the aspects of geometric effect,electronic effect,synergistic effect,defect engineering,support effect was concluded.Then,the latest progress and the practical application of Ir-based catalysts were introduced in detail,which was classified into the varied composition of Ir catalyst in terms of alloys,hetero-element doping,perovskite,pyrochlore,heterostructure,core-shell structure,and supported catalysts.Finally,the problems and challenges faced by the current Ir-based catalyst in the acidic electrolyte were put forward.It is concluded that highly efficient catalysts with low Ir loading should be developed in the future,and attention should be paid to probing the structural and performance correlation,and their application in real PEMWE devices.Hopefully,the current effort can be helpful in the catalysis mechanism understanding of Ir-based catalysts for OER,and instructive to the novel efficient catalysts design and fabrication.
基金supported by the National Natural Science Foundation of China(Nos.U23A20153,and 32101319).
文摘Sediment properties have a crucial effect on the growth and recovery of aquatic plants in lakes.Addition of various chemical substances has been proposed to reinforce the recovery of plants after a nutrient loading reduction.However,the effects of such sediment amendments on plant growth,especially those from rhizosphere microorganisms,is limited.We added Kaolin clay to sediments in different concentrations to explore its impact on the growth of Vallisneria natans and Ottelia acuminate and the concurrent shift in rhizosphere microorganisms using high-throughput sequencing technology.We found that the addition of low doses(10%and 20%in mass ratio)of Kaolin significantly modified sediment conditions(oxidation reduction potential and pH),with implications also for the composition,diversity,and stability of rhizosphere microorganisms.LEfSe analysis revealed that low-dose addition of Kaolin increased the abundances of functional microbial groups that benefit plant nutrient absorption and enhance plant stress resistance,such as Spirillaceae,Rhodocyclaceae,and Burkholderiales.Moreover,low doses of Kaolin significantly promoted the photosynthesis and nutrient absorption of submerged macrophytes,thereby facilitating plant growth.A structural equation model(SEM)indicated that the direct impact of Kaolin on the growth of submerged plants was relatively minor,while the indirect effect through modulation of rhizosphere microorganisms was important.Our study suggests that low doses of Kaolin may be used to promote the growth of submerged macrophytes when lakes with a high organic content in the sediment are recovering after nutrient loading reduction.
基金supported by the National Natural Science Foundation of China(21403125,21403124)the Scientific Research Foundation for the Outstanding Young Scientist of Shandong Province(BS2011NJ009)~~
文摘Fe_2O_3 nanorods and hexagonal nanoplates were synthesized and used as the promoters for Pt electrocatalysts toward the methanol oxidation reaction（MOR） in an alkaline electrolyte.The catalysts were characterized by scanning electron microscopy,transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,cyclic voltammetry and chronoamperometry.The results show that the presence of Fe_2O_3 in the electrocatalysts can promote the kinetic processes of MOR on Pt,and this promoting effect is related to the morphology of the Fe_2O_3 promoter.The catalyst with Fe_2O_3 nanorods as the promoter（Pt-Fe_2O_3/C-R） exhibits much higher catalytic activity and stability than that with Fe_2O_3 nanoplates as the promoter（Pt-Fe_2O_3/C-P）.The mass activity and specific activity of Pt in a Pt-Fe_2O_3/C-R catalyst are 5.32 A/mgpt and 162.7 A/m^2_（Pt）,respectively,which are approximately 1.67 and 2.04 times those of the Pt-Fe_2O_3/C-P catalyst,and 4.19 and 6.16 times those of a commercial PtRu/C catalyst,respectively.Synergistic effects between Fe_2O_3 and Pt and the high content of Pt oxides in the catalysts are responsible for the improvement.These findings contribute not only to our understanding of the MOR mechanism but also to the development of advanced electrocatalysts with high catalytic properties for direct methanol fuel cells.
基金financially supported by the National Key R&D Program of China (2016YFC0204201)the National Natural Science Foundation of China (21677114, 21477095, 21876139)the Fundamental Research Funds for the Central Universities (xjj2017170)~~
文摘Pt/Eu2O3-CeO2 materials with different Eu concentrations were prepared and applied to toluene destruction,and the remarkable promotion impact of EuOx on Pt/CeO2 can be observed.The characterization results reveal that the presence of EuOx significantly enhances the redox property,lattice O concentration,and Ce3+ ratio of the Pt/CeO2 material,which facilitates the dispersion and activity of Pt active sites and thus accelerates the decomposition process of toluene.Among all catalysts,a sample with an Eu content of 2.5 at.%(Pt/EC-2.5)possesses the best catalytic activity with 0.09 vol% of toluene completely destructed at 200 ℃ under a relatively high GHSV of 50000 h^-1.The possible reaction pathway and mechanism of toluene combustion over Pt/Eu2O3-CeO2 samples are presented according to in-situ DRIFTS,which confirms that the toluene oxidation process obeys the Mars-van Krevelen mechanism with aldehydes and ketones as primary organic intermediates.
基金The work was jointly supported by two grants(Project code:UIC 201624 and UIC 201714)from Beijing Normal University-Hong Kong Baptist University United International College,Zhuhai,Guangdong,China.
文摘The seeds and sprouts of mung bean are very common cruise in Asia.Evidence showed that bioactive compounds in mung bean have emerged as an increasing scientific interest due to their role in the prevention of degenerative diseases.All data of in vitro,in vivo and clinical studies of mung bean and its impact on human health were collected from a library database and electronic search.Botanical,phytochemical and pharmacological information was gathered and orchestrated.Remarkable studies have been demonstrated,showing the enhancement of metabolites in mung bean during the sprouting process,which possesses various health benefiting bioactive compounds.These compounds have been frequently attributed to their antioxidant,anti-diabetic,antimicrobial,anti-hyperlipidemic and antihypertensive effect,anti-inflammatory,and anticancer,anti-tumor and anti-mutagenic properties.In this critical review,we aimed to study the insight of the nutritional compositions,phytochemistry,and healthpromoting effects of mung bean and its sprouts.The various curative potential of mung bean provides successive preclinical outcomes in the field of drug discovery and this review strongly recommends that mung bean is an excellent nutritive legume,which modulates or prevents chronic degenerative diseases.
基金supported by the National Natural Science Foundation of China(Nos.52176099,51376007 and 51806001)the Project of Jiangsu Provincial Six Talent Peak,China(No.JNHB-097)。
文摘This paper presents how the combustion performance of nano-sized aluminum(nAl)powder in carbon dioxide are affected by silica. The ignition and combustion performance of nAl powder with silica addition were studied by a high-temperature tube furnace. An s-type thermocouple and a high-speed motion acquisition instrument were performed to evaluate the ignition temperature, maximum combustion temperature, maximum change of rate of temperature, and combustion propagation speed. The combustion efficiency and combustion products were measured and analyzed by a gas-volumetric method and an X-ray diffraction. The results show that silica added into nAl powder can enhance its maximum combustion temperature and maximum change of rate of temperature, while its ignition temperature increases slightly. The nAl powders with addition of 6.00 wt.% and 12.00 wt.% silica present high combustion propagation speeds, especially for the latter, it has high combustion efficiency. The effect mechanism of silica on the combustion of nAl powder in carbon dioxide was discussed.
基金financially supported from the National Natural Science Foundation of China(Nos.12074048 and 12147102)the Project for Fundamental and Frontier Research in Chongqing(No.cstc2020jcyj-msxm X0796)the Fundamental Research Funds for the Central Universities(No.2022CDJXY-002)。
文摘The construction of highly active catalysts for methanol oxidation reaction(MOR)is central to direct methanol fuel cells.Tremendous progress has been made in transition metal phosphides(TMPs)based catalysts.However,TMPs would be partially damaged and transformed into new substances(e.g.,Pt-M-P composite,where M represents a second transition metal)during Pt deposition process.This would pose a large obstacle to the cognition of the real promoting effects of TMPs in MOR.Herein,Co_(2)P co-catalysts(Pt-P/Co_(2)P@NPC,where NPC stands for N and P co-doped carbon)and Pt-Co-P composite catalysts(Pt-CoP/NPC)were controllably synthesized.Electrocatalysis tests show that the Pt-Co-P/NPC exhibits superior MOR activity as high as 1016 m A/mg_(Pt),significantly exceeding that of Pt-P/Co_(2)P@NPC(345 m A/mg_(Pt)).This result indicates that the promoting effect is ascribed primarily to the resultant Pt-Co-P composite,in sharply contrast to previous viewpoint that Co_(2)P itself improves the activity.Further mechanistic studies reveal that Pt-Co-P/NPC exhibits much stronger electron interaction and thus manifesting a remarkably weaker CO absorption than Pt-P/Co_(2)P@NPC and Pt/C.Moreover,Pt-Co-P is also more capable of producing oxygen-containing adsorbate and thus accelerating the removal of surface-bonded CO^(*),ultimately boosting the MOR performance.
基金the National High Technology Research and Development Program of China(Grant No.2009AA063003)the National Nature Science Foundation of China(Grant No.20677039) for financial support
文摘A significant promotion effect of low-molecular hydroxyl compounds(LMHCs) was found in the nano-photoelectrocatalytic(NPEC) degradation of fulvic acid(FA),which is a typical kind of humic acid existing widely in natural water bodies,and its influence mechanism was proposed.A TiO_2 nanotube arrays(TNAs) material is served as the photoanode.Methanol,ethanediol,and glycerol were chosen as the representative of LMHCs in this study.The adsorption performance of organics on the surface of TNAs was investigated by using the instantaneous photocurrent value.The adsorption constants of FA,methanol,ethanediol,and glycerol were 43.44,19.32,7.00,and 1.30,respectively,which indicates that FA has the strongest adsorption property.The degradation performance of these organics and their mixture were observed in a thin-layer reactor.It shows that FA could hardly achieve exhausted mineralization alone,while LMHCs could be easily oxidized completely in the same condition.The degradation degree of FA,which is added LMHCs,improves significantly and the best promotion effect is achieved by glycerol.The promotion effect of LMHCs in the degradation of FA could be contributed to the formation of a tremendous amount of hydroxyl radicals in the NPEC process.The hydroxyl radicals could facilitate the complete degradation of both FA and its intermediate products.Among the chosen LMHCs,glycerol molecule which has three hydroxyls could generate the most hydroxyl radicals and contribute the best effective promotion.This work provides a new way to promote the NPEC degradation of FA and a direction to remove humus from polluted water.
基金Funded by the Major Sqpecial Technological Programmes Concerning Water Pollution Control and Management(No. 2008ZX07317-02)
文摘Tourmaline can promote the growth of microorganisms under the temperature less than 900 ℃ by experiment. However, this promotion effect will vanish at 900 ℃ as a result of denaturation. Through the XRD analysis the crystal form change can explain the vanishment of tourmaline’s biological promotion effect at high temperature. Therefore, tourmaline as a biological promoter was used to prepare a kind of biological promotive ceramsite with the surface area of 7.914 m2/g, pore volume of 0.1002 mg/L, superficial pH value of 7.8, Zeta potential of 25 mV, unit water absorption of 0.1365 g/g, biocompatibility of 0.023 A/g and SICE of 0.8456. The experimental results show that the biomass of biological promotive ceramsite is 3.58 times more than that of ordinary ceramsite, and the treatment effect of the biological promotive ceramsite is better than the ordinary ceramsite. These features of this new biological promotive ceramsite makes it a preferable biovector.
基金Financial support from the National Natural Science Foundation of China,China(Nos.21972062,21976081,21976111)。
文摘A simple strategy of Cu modification was proposed to broaden the operation temperature window for NbCe catalyst.The best catalyst Cu0.010/Nb1Ce3 presented over 90%NO conversion in a wide temperature range of 200-400℃and exhibited an excellent H_(2)O or/and SO_(2) resistance at 275℃.To understand the promotional mechanism of Cu modification,the correlation among the"activity-structure-property"were tried to establish systematically.Cu species highly dispersed on NbCe catalyst to serve as the active component.The strong interaction among Cu,Nb and Ce promoted the emergence of NbO4 and induced more Bronsted acid sites.And Cu modification obviously enhanced the redox behavior of the NbCe catalyst.Besides,EPR probed the Cu species exited in the form of monomeric and dimeric Cu^(2+),the isolated Cu^(2+)acted as catalytic active sites to promote the reaction:Cu^(2+)-NO_(3)^(-)+NO(g)→Cu^(2+)-NO_(2)^(-)+NO_(2)(g).Then the generated NO_(2) would accelerate the fast-SCR reaction process and thus facilitated the lowtemperature deNO_(x) efficiency.Moreover,surface nitrates became unstable and easy to decompose after Cu modification,thus providing additional adsorption and activation sites for NH3,and ensuring the improvement of catalytic activity at high temperature.Since the NH3-SCR reaction followed by E-R reaction pathway efficaciously over Cu_(0.010)/Nb_(1)Ce_(3) catalyst,the excellent H_(2)O and SO_(2) resistance was as expected.
基金supported by the National Natural Science Foundation of China (No. 21207039)the Natural Science Foundation of Guangdong Province, China (Grant No. S2011010000737)+2 种基金the Doctoral Fund of Ministry of Education of China (20110172120017)the Fundamental Research Funds for the Central Universities (Grant No. 2011zm 0048)the Key Laboratory of Renewable Energy and Gas Hydrate, Chinese Academy of Sciences (No. Y007K1)
文摘Activated carbon （AC） supported silver catalysts were prepared by incipient wetness impregnation method and their catalytic performance for CO preferential oxidation （PROX） in excess H2 was evaluated. Ag/AC catalysts, after reduction in H2 at low temperatures （≤200 ℃） following heat treatment in He at 200 ℃ （He200H200）, exhibited the best catalytic properties. Temperature-programmed desorption （TPD）, X-ray diffraction （XRD） and temperature-programmed reduction （TPR） results indicated that silver oxides were produced during heat treatment in He at 200 ℃ which were reduced to metal silver nanoparticles in H2 at low temperatures （≤200 ℃）, simultaneously generating the adsorbed water/OH. CO conversion was enhanced 40% after water treatment following heat treatment in He at 600 ℃. These results imply that the metal silver nanoparticles are the active species and the adsorbed water/OH has noticeable promotion effects on CO oxidation. However, the promotion effect is still limited compared to gold catalysts under the similar conditions, which may be the reason of low selectivity to CO oxidation in PROX over silver catalysts. The reported Ag/AC-S-He catalyst after He200H200 treatment displayed similar PROX of CO reaction properties to Ag/SiO2. This means that Ag/AC catalyst is also an efficient low-temperature CO oxidation catalyst.
文摘The effects of riboflavin deficiency and simultaneously nitrosodimethylamine (NDMA) given by gastric intubation on the hepatic glutathione (GSH) content were examined in rats. On different days of the experiment, hepatic GSH content of the riboflavin deficient rats decreased to 55-61% of the control rats. When NDMA was given 6 mg kg by gastric intubation to riboflavin deficient rats, hepatic GSH content decreased markedly to 39-43% of the control rats. After supplying riboflavin, hepatie GSH content of the deficient rats recovered to the level of the control rats. These results suggest that alterations of rat hepatic GSH content during riboflavin deficiency may imply as one of the promoting effects of riboflavin deficiency on the carcinogenesis of nitrosamines.
文摘Basicity of ZrO2 is enhanced by KF modification due to the reaction of KF with ZrO2 surface: KF+ ZrO2-> K2ZrF6 + KOH. After pretreated above 673K, KF/ZrO2 catalyst exhibited higher activity for 1-butene isomerization at 273K than ZrO2. The amount of basic sites strongly adsorbing CO2 in the form of bicarbonate was also increased.
基金The project is supported by National Natural Science Foundation of China
文摘It was found for the first time that the compounds with only one functional group, such as pyridine, can show the promotion effect for the electrochemical reaction of cytochrome C at gold electrodes.
基金the National Natural Science Foundation of China(No.32001984).
文摘A Plant Biostimulant is any substance or microorganism applied to plants to enhance nutrition efficiency,abioticstress tolerance,and/or crop quality traits,regardless of its nutrient content.The application of Plant biostimulants(PBs)in production can reduce the application of traditional pesticides and chemical fertilizers and improvethe quality and yield of crops,which is conducive to the sustainable development of agriculture.An in-depthunderstanding of the mechanism and effect of various PBs is very important for how to apply PBs reasonablyand effectively in the practice of crop production.This paper summarizes the main classification of PBs;Thegrowth promotion mechanism of PBs was analyzed from four aspects:improving soil physical and chemical properties,enhancing crop nutrient absorption capacity,photosynthesis capacity,and abiotic stress tolerance;At thesame time,the effects of PBs application on seed germination,seedling vigor,crop yield,and quality were summarized;Finally,how to continue to explore and study the use and mechanism of PBs in the future is analyzedand prospected,to better guide the application of PBs in crop production in the future.
基金financially supported by the National Natural Science Foundation of China(21173195)~~
文摘A series of K-promoted Pt/Al2O3 catalysts were tested for CO oxidation. It was found that the addition of K significantly enhanced the activity. A detailed kinetic study showed that the activation energies of the K-containing catalysts were lower than those of the K-free ones, particularly for catalysts with high Pt contents （51.6 k）/mol for 0.42K-2.0Pt/Al2O3 and 6：3.6 kJ/mol for 2.0Pt/Al2O3 ）. The CO reaction orders were higher for the K-containing catalysts （about -0.2） than for the K-free ones （about -0.5）, with the former having much lower equilibrium constants for CO adsorption than the latter. In situ Fourier-transform infrared spectroscopy showed that surface CO desorption from the 0.42K-2.0Pt/Al2O3 catalyst was easier than from 2.0Pt/Al2O3. The promoting effect of K was therefore caused by weakening of the interactions between CO and surface Pt atoms. This decreased coverage of the catalyst with CO and facilitated competitive O2 chemisorption on the Pt surface, and significantly lowered the reaction barrier between chemisorbed CO and O2 species.
基金the Ministry of Higher Education Malaysia for providing financial support to this work via FRGS No:FRGS/1/2011/SG/UTP/02/13Universiti Teknologi PETRONAS
文摘A series of novel carbon nanofibers(CNFs)based Cu-ZrO2 catalysts were synthesized by deposition precipitation method.To investigate the influence of promoter,catalysts were loaded with 1,2,3 and 4 wt%ZnO and characterized by ICP-OES,HRTEM,BET,N2O chemisorption,TPR,XPS and CO2-TPD techniques.The results revealed that physicochemical properties of the catalysts were strongly influenced by incorporation of ZnO to the parent catalyst.Copper surface area(SCu)and dispersion(DCu)were slightly decreased by incorporation of ZnO promoter.Nevertheless,SCuand DCuwere remarkably decreased when ZnO content was exceeded beyond 3 wt%.The catalytic performance was evaluated by using autoclave slurry reactor at a pressure and temperature of 30 bar and 180℃,respectively.The promotion of CuZrO2/CNFs catalyst with 3 wt%of ZnO enhanced methanol synthesis rate from 32 to 45 g kg^-1 h^-1.Notably,with the ZnO promotion the selectivity to methanol was enhanced to 92%compared to 78%of the un-promoted Cu-ZrO2/CNFs catalyst at the expense of a lowered CO2 conversion.In addition,the catalytic activity of this novel catalyst system for CO2 hydrogenation to methanol was compared with the recent literature data.
文摘The effect of super absorbent polymer（SAP） on the formation of tetrahydrofuran（THF） hydrate was studied by the successional cooling method.It was found that THF solution samples with 0.004 wt% and 0.03 wt% of SAP formed THF hydrate completely during the same cooling process.The corresponding induction time was 16-29 min,14-31 min,respectively,which was obviously shorter than that of THF solution samples without SAP（25-62 min）.It indicated that SAP accelerated the formation of THF hydrate.At the same time,the pictures of hydrate formation with and without SAP had been compared.It was found that SAP did not change the morphology of the hydrate.Finally,the mechanism of SAP promoting effect on the formation of THF hydrate was suggested.
基金financially supported by the National Natural Science Foundation of China(22078064)Natural Science Foundation of Fujian Province for Distinguished Young Scholar(2018J06002)。
文摘The hydrogenation of petroleum resin(PR)is an effective process to prepare high value-added hydrogenated PR(HPR).However,the preparation of non-noble metal-based catalysts with high catalytic activity for PR hydrogenation still remains a challenge.Herein,a La promoted Ni-based catalyst is reported through the thermal reduction of quaternary Ni La Mg Al-layered double hydroxides(Ni La Mg Al-LDHs).The incorporation of La is beneficial to the reduction and stability of Ni particles with reduced particle size,and the increased alkalinity effectively mitigates the breakage of molecular chains of PR.As a result,the La promoted Ni-based catalyst exhibits high catalytic activity and excellent stability for PR hydrogenation.A hydrogenation degree of 95.4%and 96.1%can be achieved for HC_(5)PR and HC_(9) PR with less reduced softening point,respectively.Notably,the hydrogenation degree still maintains at 92.7%even after 100 hours’reaction,much better than that without La incorporation or prepared using conventional impregnation method.
基金the financial supports from the National Natural Science Foundation of China (No. 11975082)。
文摘For the recycling of Pd and Ag from high-level liquid waste(HLLW), the electrochemical behaviors of Pd and Ag in the simulated HNO_(3) solutions were investigated by cyclic voltammetry and potentiostatic deposition.Scanning electron microscopy(SEM) and X-ray diffraction(XRD) were used to-observe the deposits morphology and to evaluate their composition. The results indicate that the formation of NO_(2)^(-)electrodeposited. When Pd and Ag are electrodeposited together, more metals are gained in the same time, and the deposited Ag does not dissolve in this situation. The metals are electrodeposited completely at the potentials from -0.4 to -0.6 V(vs MSE) and the deposits contai-n Ag and PdHx. The electrodeposition of Pd can boost h-ydrogen evolution,and then the reaction between H;and NO_(2)^(-)is sped up, thereby lowering the concentration of NO_(2)^(-)and inhibiting the dissolution of Ag.
