Phospahting coated WE43 magnesium alloy was prepared by an immersion method. The microstructure, corrosion resistance and biocompatibility of the coated alloy were investigated. Scanning electron microscopy （SEM） an...Phospahting coated WE43 magnesium alloy was prepared by an immersion method. The microstructure, corrosion resistance and biocompatibility of the coated alloy were investigated. Scanning electron microscopy （SEM） and X-ray diffraction （XRD） were used to examine the microstructure and the composition of the coated alloy. The corrosion resistance was studied by means of potentiodynamic polarization method and the biocompatibility of the surface modified WE43 alloy was evaluated by （3-（4,5）-Dimethylthiazol-2, yl）-2,5-diphenyltetrazolium bromide （MTT） and hemolysis test. The results show that the phosphating coating can enhance the corrosion resistance of WE43 alloy and can be a good candidate to increase the biocompatibility of WE43 alloy.展开更多
Silicate sol post-treatment was applied to form a complete composite coating on the phosphated zinc layer. The chemical compositions of the coatings were investigated using XPS. The coated samples were firstly scratch...Silicate sol post-treatment was applied to form a complete composite coating on the phosphated zinc layer. The chemical compositions of the coatings were investigated using XPS. The coated samples were firstly scratched and then exposed to the neutral salt spray(NSS) chamber for different time. The microstructure and chemical compositions of the scratches were studied using SEM and EDS. And the non-scratched coated samples were compared. The self-healing mechanism of the composite coatings was discussed. The results show that during corrosion, the self-healing ions in composite coatings dissolve, diffuse and transfer to the scratches or the defects, and then recombine with Zn2+ to form insoluble compound, which deposits and covers the exposed zinc. The corrosion products on the scratches contain silicon, phosphorous, oxygen, chloride and zinc, and they are compact, fine, needle and flake, effectively inhibiting the corrosion formation and expansion of the exposed zinc layer. The composite coatings have good self-healing ability.展开更多
Hydroxylamine sulfate （HAS） and sodium nitrite are used as the accelerators for zinc phos- phate coating on high carbon steel. Phase evolution of phosphate coating was investigated by X-ray diffraction. It is found ...Hydroxylamine sulfate （HAS） and sodium nitrite are used as the accelerators for zinc phos- phate coating on high carbon steel. Phase evolution of phosphate coating was investigated by X-ray diffraction. It is found that the phosphating coatings are mainly composed of hopeite Zn3Fe（PO4）2.4H2O and phosphophyllite Zn2Fe（PO4）2.4H2O. The microstructural changes of the phosphate coating, as a function of phosphating time, were evaluated by scanning elec- tron microscopy. Four-ball friction experiments reveal that hydroxylamine sulfate instead of sodium nitrite can effectively reduce the friction coefficient of lubricated phosphating coat- ing. Therefore, it may be expected that HAS will be widely used as a fast and ECO-friendly accelerator in phosphate industry.展开更多
The corrosion behavior of a NdFeB magnet obtained at room temperature,with and without ultrasonic were investigated.The corrosion resistance was investigated by corrosion immersion tests in 3 wt%neutral NaCl solutions...The corrosion behavior of a NdFeB magnet obtained at room temperature,with and without ultrasonic were investigated.The corrosion resistance was investigated by corrosion immersion tests in 3 wt%neutral NaCl solutions,potentiodynamic polarization tests and electrochemical impedance spectroscopy(EIS).The morphology of the conversion coatings on NdFeB surface were analyzed by scanning electron microscopy(SEM).And the forming mechanism of coatings was studied by potential-time curves.The tests of corrosion resistances show that the combination of phosphating treatment with ultrasonic will further improve the corrosion resistance of the NdFeB.The SEM also confirms that phosphating coating under ultrasonic is more homogeneous and compact.展开更多
Designing non-noble metal electrocatalysts toward alkaline hydrogen evolution reaction(HER)with high performance at a large current density is urgent.Herein,a CoO/CoP heterostructure catalyst(termed POZ)was designed b...Designing non-noble metal electrocatalysts toward alkaline hydrogen evolution reaction(HER)with high performance at a large current density is urgent.Herein,a CoO/CoP heterostructure catalyst(termed POZ)was designed by a phosphating strategy.The strong electron transfer on the interface of CoO/CoP was experimentally and theoretically proven.POZ showed a low overpotential of 236 mV at 400 mA/cm^(2),which was 249 mV lower than non-phosphated sample.It also exhibited a remarkable solar-to-hydrogen conversion efficiency of 10.5%.In this work,the construction of CoO/CoP interface realized by a simple phosphating strategy could provide an important reference to boost the HER performance on those materials not merely metal oxides.展开更多
Transition metal phosphide(TMP) based electrocatalysts possessing special crystal and electronic structures attract broad attention in the field of electrocatalysis.Immense effort is made to optimize TMP catalysts aim...Transition metal phosphide(TMP) based electrocatalysts possessing special crystal and electronic structures attract broad attention in the field of electrocatalysis.Immense effort is made to optimize TMP catalysts aiming to satisfy the electrochemical catalysis performance.In this work,an environmentally friendly in situ green phosphating strategy and spatial limiting effect of the RuCo precursor is employed to fabricate the ruthenium nanoclusters anchored on cobalt phosphide hollow microspheres(Ru NCs/Co_(2)P HMs).The obtained Ru NCs/Co_(2)P HMs electrocatalysts exhibit high hydrogen evolution reaction(HER) activity at wide pH ranges,which require an overpotential of 77 mV to achieve the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4) and 118 mV in 1.0 mol/L KOH.Besides,the multifunctional Ru NCs/Co_(2)P HMs exhibit good oxygen evolution reaction(OER) activity with an overpotential of 197 mV to reach the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4),which is below that of the commercial RuO_(2) electrocatalyst(248 mV).A two-electrode electrolyzer is assembled as well,in acid electrolyte,it achieves a current density of 10 mA/cm^(2) at a voltage of 1.53 V,which is superior to that of the benchmark of precious metal-based electrolyzer(1.58 V).展开更多
Zinc phosphate coating formed on 6061-A1 alloy was studied with the help of electrochemical measurements, Fourier Transform Infrared （FTIR）, and Scanning Electron Microscopy （SEM）, after dipping it in phosphating ...Zinc phosphate coating formed on 6061-A1 alloy was studied with the help of electrochemical measurements, Fourier Transform Infrared （FTIR）, and Scanning Electron Microscopy （SEM）, after dipping it in phosphating solutions containing different concentrations of Rare Earth Nitrate （REN）. REN, which acted as an accelerator in the phosphating solution, could catalyze the surface reaction and accelerate the phosphating process. REN mainly enabled the P in the phosphate coating to exist in the form of PO4^3- and promoted the hydrolysis of phosphatic acid in a liquid layer at the cathodes. This resulted in the evolution of H2 at the cathodes, which increased the local pH value and in turn drove the precipitation of the phosphate coating. Additionally, REN was adsorbed on the surface of the aluminum substrates to form a gel during the phosphating process. These gel particles were good crystal seeds, which helped to form phosphate crystal nuclei and possess the function of a nucleation agent that could decrease the phosphate crystal size. The corrosion resistance of the formed zinc phosphate coatings was improved.展开更多
To improve the corrosion resistance of phosphate coatings, the phosphated hot-dip galvanized (HDG) steel was post-sealed with cerium nitrate solution. The morphology, composition, corrosion resistance of the coatings ...To improve the corrosion resistance of phosphate coatings, the phosphated hot-dip galvanized (HDG) steel was post-sealed with cerium nitrate solution. The morphology, composition, corrosion resistance of the coatings was investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and neutral salt spray (NSS) tests. The results show that after post-sealing the phosphated HDG samples with cerium nitrate solution, the pores among the zinc phosphate crystals are sealed by the compounds containing phosphorus, oxygen and cerium; the zinc phosphate crystals are covered by the flocculent cerium compounds; and the continuous composite coatings are formed on HDG steel. The corrosion resistance of the composite coatings, which increases with the increase in phosphating time and cerium nitrate post-sealing time, is far higher than that of the single phosphate coatings. The composite coatings with the optimal corrosion resistance are obtained for phosphating 300 s and post-sealing 300 s; and the corrosion resistance is more outstanding than that of the chromate coatings.展开更多
The phosphated and cerium nitrate post-sealed galvanized steel was firstly scratched to expose zinc layer and then placed in neutral salt spray （NSS） chamber for different durations. The microstructure and compositi...The phosphated and cerium nitrate post-sealed galvanized steel was firstly scratched to expose zinc layer and then placed in neutral salt spray （NSS） chamber for different durations. The microstructure and compositions of the scratches were investigated using SEM and EDS. The phases of the corrosion products were examined through XRD. The self-healing mechanism of the composite coatings was discussed. The experimental results show that the composite coatings have an excellent corrosion resistance. The corrosion products increase with corrosion time and finally cover the whole scratch. They contain phosphorous, cerium, oxygen, chloride and zinc, and are fine needle and exceedingly compact. The composite coatings are favorable self-healing. During corrosion, the self-healing ions such as Ce3＋, Ce4＋, PO43-, Zn2＋ in the composite coatings were dissolved, migrated, recombined, and covered the exposed zinc, impeding zinc corrosion. The self-healing process of the scratches on the composite coatings can be divided into three stages, about 2 h, 4 h, and 24 h, respectively.展开更多
Zinc phosphate coatings formed on 6061-Al alloy, after dipping in phosphating solutions containing different amounts of Y2O3（yttrium oxide）, were studied by scanning electron microscopy （SEM）, X-ray diffraction （...Zinc phosphate coatings formed on 6061-Al alloy, after dipping in phosphating solutions containing different amounts of Y2O3（yttrium oxide）, were studied by scanning electron microscopy （SEM）, X-ray diffraction （XRD） and electrochemical measurements. Significant variations in the morphology and corrosion resistance afforded by zinc phosphate coating were especially observed as Y2O3 in phosphating solution varied from 0 to 40 mg/L. The addition of Y2O3 changed the initial potential of the interface between aluminum alloy substrate and phosphating solution and increased the number of nucleation sites. The phosphate coating thereby was less porous structure and covered the surface of aluminum alloy completely within short phosphating time. Phosphate coating was mainly composed of Zn3（PO4）2·4H2O （hopeite） and AlPO4（aluminum phosphate）. Y2O3, as an additive of phosphatization, accelerated precipitation and refined the gain size of phosphate coating. The corrosion resistance of zinc phosphate coating in 3% NaCl solution was improved as shown by polarization measurement. In the present research, the optimal amount of Y2O3 was 10-20 mg/L, and the optimal phosphating time was 600 s.展开更多
The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion batteries.Lithium manganese iron phosphate(LiMn_(x)Fe_(1-x)PO_(4))has garnered...The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion batteries.Lithium manganese iron phosphate(LiMn_(x)Fe_(1-x)PO_(4))has garnered significant attention as a promising positive electrode material for lithium-ion batteries due to its advantages of low cost,high safety,long cycle life,high voltage,good high-temperature performance,and high energy density.Although LiMn_(x)Fe_(1-x)PO_(4)has made significant breakthroughs in the past few decades,there are still facing great challenges in poor electronic conductivity and Li-ion diffusion,manganese dissolution affecting battery cycling performance,as well as low tap density.This review systematically summarizes the reaction mechanisms,various synthesis methods,and electrochemical properties of LiMn_(x)Fe_(1-x)PO_(4)to analyze reaction processes accurately and guide material preparation.Later,the main challenges currently faced are concluded,and the corresponding various modification strategies are discussed to enhance the reaction kinetics and electrochemical performance of LiMn_(x)Fe_(1-x)PO_(4),including multi-scale particle regulation,heteroatom doping,surface coating,as well as microscopic morphology design.Finally,in view of the current research challenges faced by intrinsic reaction processes,kinetics,and energy storage applications,the promising research directions are anticipated.More importantly,it is expected to provide key insights into the development of high-performance and stable LiMn_(x)Fe_(1-x)PO_(4)materials,to achieve practical energy storage requirements.展开更多
Guided bone regeneration in the alveolar bone relies on the colonization and differentiation of immune cells within the defect area.The absence of osteoinductive and osteoimmune properties of currently available scaff...Guided bone regeneration in the alveolar bone relies on the colonization and differentiation of immune cells within the defect area.The absence of osteoinductive and osteoimmune properties of currently available scaffolds hinders to achieve optimal repair outcomes in clinical settings.Thus,we aimed to enhance the bone repair ability of polycaprolactone(PCL)scaffolds by incorporating osteoinductive amorphous calcium phosphate(ACP)with immune-regulating zinc ions(ACP(Zn),ACZP),to create a favorable immunomodulatory microenvironment.After one day of co-culture with PCL-ACZP,the spreading area of macrophage cells was significantly higher than that from the original PCL scaffold.Additionally,over 32.1%of macrophages exhibited M2 polarization within three days of co-culture.The PCLACZP/macrophage-conditioned medium significantly boosted osteogenic gene expression in MC3T3-E1 cells.After eight weeks of implantation in a rat femoral condyle defect,the BV/TV from the PCL-ACZP group reached 32.9%,1.4 times of that from the PCL group.Furthermore,the PCL-ACZP-GelMA biphasic module as prepared successfully achieved complete regeneration of three-walled alveolar bone defects in rabbits,resulting in arch-shaped alveolar bone repair and providing greater convenience in the clinical settings.This study showcased the effectiveness of PCL-ACZP-GelMA biphasic module as bioactive scaffolds in the morphological restoration of alveolar bone.展开更多
In this study,a phosphate-based conversion coating(PCC)was applied as a precursor before forming silicate-fluoride(SiF)and silicate-phosphate-fluoride(SiPF)based flash-plasma electrolytic oxidation(Flash-PEO)coatings ...In this study,a phosphate-based conversion coating(PCC)was applied as a precursor before forming silicate-fluoride(SiF)and silicate-phosphate-fluoride(SiPF)based flash-plasma electrolytic oxidation(Flash-PEO)coatings on AZ31B magnesium alloy.The main novelty is the successful incorporation of calcium,zinc,manganese and phosphate species into the Flash-PEO coatings via a precursor layer rather than using the electrolyte.The precursor also led to longer lasting and more intense discharges during the PEO process,resulting in increased pore size.Corrosion studies revealed similar short-term performance for all coatings,with impedance modulus at low frequencies above 10^(7)Ωcm^(2),and slightly better performance for the SiPF-based coating.Nonetheless,the enlarged pores in the PEO coatings functionalized with the PCC precursor compromised the effectiveness of self-healing mechanisms by creating diffusion pathways for corrosive species,leading to earlier failure.These phenomena were effectively monitored by recording the open circuit potential during immersion in 0.5 wt.%NaCl solution.In summary,this study demonstrates that conversion coatings are a viable option for the functionalization of PEO coatings on magnesium alloys,as they allow for the incorporation of cationic and other species.However,it is crucial to maintain a small pore size to facilitate effective blockage through self-healing mechanisms.展开更多
In this study,synthetic wastewater containing 110μg/L arsenate(As(V)),0-20 mg/L fulvic acid(FA),and 0-12.3 mg/L phosphate was treated with 3 mg/L Fe3+.The mechanisms of FA and phosphate effects on As(V)removal by fer...In this study,synthetic wastewater containing 110μg/L arsenate(As(V)),0-20 mg/L fulvic acid(FA),and 0-12.3 mg/L phosphate was treated with 3 mg/L Fe3+.The mechanisms of FA and phosphate effects on As(V)removal by ferric chloride were determined using 0.22-10μm pore-size filtration,Zetasizer analysis,and in situ flow through cell ATR-FTIR.The results showed that up to 20mg/L FA had almost no effect on the solubility of ferric hydroxide precipitates and adsorption of As(V)by the precipitates.When FA concentration increased from 0 to 20 mg/L,the adsorption of FA led to higher negative zeta potential of the precipitates and the strong electrostatic repulsion between the precipitates decreased the particle size of ferric hydroxide flocs fromlarger than 10μmto smaller than 1μm.In the presence of 5-20 mg/L FA,46%-63%As(V)was adsorbed onto the flocs with particle size in the range of 0.45-1μm.On the other hand,phosphate did not affect the size of ferric hydroxide flocs and significantly increased the dissolved As(V)concentration because it competed with As(V)for adsorption sites on ferric hydroxide precipitates.The addition of 5mg/L cationic organic flocculant significantly reduced the effect of FA on As(V)removal,but did not reduce the effect of phosphate on As(V)removal.The findings of this study will help develop effective arsenic treatment techniques and predict the mobility of arsenic in the environment.展开更多
The green energy transition relies heavily on critical metals,such as rare earth elements(REEs).However,their reserves are primarily focused in a few countries,such as China,which accounts for approximately 70%of glob...The green energy transition relies heavily on critical metals,such as rare earth elements(REEs).However,their reserves are primarily focused in a few countries,such as China,which accounts for approximately 70%of global production.Hence,several countries are currently looking for alternative resources for REEs.Alternative REE resources in the supply chain include recycling of e-waste,industrial waste like red mud and phosphogypsum,coal ash,mine tailings,ocean floor sediments,and even certain types of sedimentary deposits like phosphorites where REEs are present in lower concentrations but at larger volumes compared to primary ore deposits which are becoming targets by REEs industry.Currently,several studies are going on the development of eco-friendly REEs extraction technologies from phosphorite deposits.Consequently,advanced data analysis tools,such as Machine Learning(ML),are becoming increasingly important in mineral prospectivity and are rapidly gaining traction in the earth sciences.Phosphorite deposits are mainly used to manufacture fertilizers as these rocks are known for their significant phosphorus content.Moreover,these formations are considered a prospective resource of REEs.The different types of phosphorite deposits such as continental,seamount,and ore deposits worldwide reported concentrations of∑REE upto 18,000µg/g.Due to the augmented claim of REEs for various ultra-modern,and green technology applications that are required to switch over to a carbon-neutral environment,these phosphorite deposits have become an important target mostly because of their relatively higher content of REEs especially heavy rare earth elements(HREE).For example,Mississippian phosphorites reported ∑ HREE 7,000µg/g.To have a comprehensive understanding of the REEs potential of these phosphorite deposits which also include several Chinese phosphorite deposits,this study is undertaken to review the phosphorite deposits in the world and their REEs potential,in addition to some of the associated aspects such as applications and formation mechanisms for different types of phosphorite deposits such as igneous phosphate deposits,sedimentary phosphorite deposits,marine phosphorite deposits,cave phosphate deposits,and insular guano deposits.Other important aspects include their occurrences,types,geochemical characteristics,the REEs enrichment mechanisms,and various recovery methods adopted to recover REEs from different phosphorite deposits.The present review paper concludes that the recent studies highlight the global potential of phosphorite deposits to satisfy the increasing demand for REEs.Extracting REEs from phosphorite presents no significant technological or environmental difficulties,as long as radioactive elements are eliminated.In India,more comprehensive geological surveys,along with the advancement of new methods and evaluations,are required to locate phosphorite deposits with high concentrations of REEs.展开更多
Whilst phosphorus(P)in soil is considered to be abundant,the portion available for plant uptake constitutes less than 1%of the overall P present.To enhance crop productivity,the utilization of mineral P fertilizers ha...Whilst phosphorus(P)in soil is considered to be abundant,the portion available for plant uptake constitutes less than 1%of the overall P present.To enhance crop productivity,the utilization of mineral P fertilizers has become pervasive in agriculture.Nonetheless,the escalating prices of chemical fertilizers,coupled with new European regulations prohibiting the use of P fertilizers containing cadmium,have highlighted the urgency to identify environmentally friendly products and practices for P fertilization in agricultural soils.This comprehensive review delves into the current landscape of P fertilization from agricultural,political,and economic standpoints.We recognize the potential of microbes in mobilizing P,but emphasize the necessity for more robust research to establish their effectiveness in promoting plant P uptake under real-world conditions.Additionally,we explore the role of agricultural conservation practices,such as optimal tillage,diversified cropping systems,and increased organic carbon input,in conserving P.Furthermore,this review contemplates forthcoming innovations in research.These innovations encompass the development of enhanced formulations for biofertilizers and the undertaking of more comprehensive studies within the realm of conservation agriculture.All these endeavors collectively hold the potential to augment P accessibility to plants in a sustainable manner,thereby advancing agricultural sustainability and productivity.展开更多
The interaction mechanism between eggshell calcium and endogenous silica in biomass during biochar modification,and its impact on phosphate adsorption performance and slow-release fertilizer characteristics,remains un...The interaction mechanism between eggshell calcium and endogenous silica in biomass during biochar modification,and its impact on phosphate adsorption performance and slow-release fertilizer characteristics,remains unexplored.This study investigates that high silica content in biomass(>6%)inhibits the decomposition of CaCO_(3)in eggshells during pyrolysis,reducing the formation of active calcium species(CaO and Ca(OH)_(2)),while moderate silica levels(4%-5%)promote the formation of CaSiO_(3),enhancing phosphorus adsorption without hindering Ca^(2+)activation.Adsorption studies reveal that the precipitation of Ca_(5)(PO_(4))_(3)(OH)resulting from the combination of CaO and Ca(OH)_(2)with phosphate is the primary and effective form for phosphorus removal in calcium-modified adsorbents,accompanied by Ca_(3)(PO_(4))_(2)·2H_(2)O precipitation formed by CaSi O_(3).Eggshell calcium-modified corn straw biochar(ECS)exhibited the highest adsorption capacity,reaching 123.3 mg/g,outperforming materials in previous studies.ECS also demonstrated excellent pH adaptability and selective phosphate removal.As a biochar-based phosphorus fertilizer,ECS-P exhibits high phosphorus extractability in formic acid(93.92%)but low water solubility(0.62%),with phosphorus release during the seven-day intermittent leaching experiment remaining between 0.53 to 0.875 mg/L.These results confirm its potential as a phosphorus cycling fertilizer.This study provides fundamental insights into optimizing biomass selection based on silica content for calcium modification,offering an efficient strategy for both phosphate recovery and slow-release fertilizer development.展开更多
The efficient recycling of spent lithium iron phosphate(LiFePO_(4),also referred to as LFP)should convert Fe(Ⅱ)to Fe(Ⅲ),which is key to the extraction of Li and separation of Fe and is not well understood.Herein,we ...The efficient recycling of spent lithium iron phosphate(LiFePO_(4),also referred to as LFP)should convert Fe(Ⅱ)to Fe(Ⅲ),which is key to the extraction of Li and separation of Fe and is not well understood.Herein,we systematically study the oxidation of LiFePO_(4)in the air and in the solution containing oxidants such as H_(2)O_(2)and the effect of oxidation on the leaching behaviors of LFP.In the air,O_(2)breaks down the LFP olivine structure at 550℃for 1 h by oxidizing Fe(Ⅱ)to Fe(Ⅲ)in terms of converting LFP to Li_(3)Fe_(2)(PO_(4))_(3)and Fe_(2)O_(3).After that,Li is leached in 0.5 M sulfuric acid solution and is further recycled as Li_(3)PO_(4)with a Li recovery efficiency of 97.48%.Meanwhile,Fe is recovered as FePO_(4)and Fe_(2)O_(3).Compared with H_(2)SO_(4)-H_(2)O_(2),the air oxidation saves H_(2)O_(2)but increases the leaching efficiency of Fe and H_(2)SO_(4)consumption.The discrepancy of Fe leaching efficiency can be attributed to the different leaching mechanisms involving the solid-to-solid and solid-to-liquid-to-solid conversions.Furthermore,the results of the Everbatt model analysis show that the air roasting-H_(2)SO_(4)leaching method has low emission and potentially high income,which is simple and safe.Overall,this work will deepen the understanding of acid leaching of LFP and favorably stimulate the maturation of the LFP recycling technique.展开更多
Pure Mg boasting a relatively small corrosion rate is a potential biodegradable metal material for implants.However,its degradation behavior in the complex physiological environment is still a lack of understanding.In...Pure Mg boasting a relatively small corrosion rate is a potential biodegradable metal material for implants.However,its degradation behavior in the complex physiological environment is still a lack of understanding.In this work,we investigated the effect of corrosion product film layers on the degradation behavior of pure Mg in physiological environments.Pure Mg shows a faster corrosion rate in simulated body fluid(SBF)compared to NaCl solution.Hydrogen evolution experiments indicate that the degradation rate of pure Mg in SBF decreases rapidly within the first 12 h but stabilizes afterward.The rapid deposition of low-solubility calcium phosphate on the pure Mg in SBF provides protection to the substrate,resulting in a gradual decrease in the degradation rates.Consequently,the corrosion product film of pure Mg formed in SBF exhibits a layered structure,with the upper layer consisting of dense Ca_(3)(PO_(4))_(2)/Mg_(3)(PO_(4))_(2) and the lower layer consisting of Mg(OH)_(2)/MgO.Electrochemical impedance spectroscopy(EIS)shows that the resistance of the corrosion product film increases over time,indicating gradual strengthening of the corrosion resistance.The 4-week degradation results in the femoral marrow cavity of mice are consistent with the result in SBF in vitro.展开更多
Developing high-efficient and low-loading Pt based catalyst is significant for the electrocatalytic p Huniversal hydrogen evolution reaction(HER). Herein, the molybdenum carbide nanoparticles supported on the polyhedr...Developing high-efficient and low-loading Pt based catalyst is significant for the electrocatalytic p Huniversal hydrogen evolution reaction(HER). Herein, the molybdenum carbide nanoparticles supported on the polyhedral N-doped carbon nanotube skeleton(Mo C/NCT) composite has been synthesized by a pyrolysis of polyacid organo-metallic phosphate framework precursor. Then, only 2.15 wt% Pt are loaded on the Mo C/NCT to form Pt-Mo C/NCT catalyst, which performs superior HER activity and stability in entire p H range. Specially, the overpotentials of 22 and 74 m V are respectively attained at 10 m A/cm^(2) in1.0 mol/L KOH and 0.5 mol/L H_(2)SO_(4) electrolytes, approaching or even exceeding commercial Pt/C. More importantly, it can be used as excellent catalyst for efficient hydrogen production at 0–14 p H range. Density functional theory(DFT) calculations demonstrate that the interaction between Mo C and Pt leads to the electron redistribution at the corresponding interfaces and the downward shift of the d-band centers, thus optimizing H*adsorption and desorption for promoting the HER activity. Besides, the unique three-dimensional network structure is conductive to the transmission of mass and electrons. In the application of both alkaline and acidic electrolysers, only 1.52 V voltage of solar panel can drive a hydrogen production current density of 10 m A/cm^(2).展开更多
基金Project(2011AA030103) supported by the National High-tech Research Program of ChinaProject(201001C0104669453) supported by the Guangdong Innovation R&D Team Project,China
文摘Phospahting coated WE43 magnesium alloy was prepared by an immersion method. The microstructure, corrosion resistance and biocompatibility of the coated alloy were investigated. Scanning electron microscopy （SEM） and X-ray diffraction （XRD） were used to examine the microstructure and the composition of the coated alloy. The corrosion resistance was studied by means of potentiodynamic polarization method and the biocompatibility of the surface modified WE43 alloy was evaluated by （3-（4,5）-Dimethylthiazol-2, yl）-2,5-diphenyltetrazolium bromide （MTT） and hemolysis test. The results show that the phosphating coating can enhance the corrosion resistance of WE43 alloy and can be a good candidate to increase the biocompatibility of WE43 alloy.
基金Project(2012J05099)supported by the Natural Science Foundation of Fujian Province,ChinaProject(YKJ10021R)supported by the Scientific Research Project of Xiamen University of Technology
文摘Silicate sol post-treatment was applied to form a complete composite coating on the phosphated zinc layer. The chemical compositions of the coatings were investigated using XPS. The coated samples were firstly scratched and then exposed to the neutral salt spray(NSS) chamber for different time. The microstructure and chemical compositions of the scratches were studied using SEM and EDS. And the non-scratched coated samples were compared. The self-healing mechanism of the composite coatings was discussed. The results show that during corrosion, the self-healing ions in composite coatings dissolve, diffuse and transfer to the scratches or the defects, and then recombine with Zn2+ to form insoluble compound, which deposits and covers the exposed zinc. The corrosion products on the scratches contain silicon, phosphorous, oxygen, chloride and zinc, and they are compact, fine, needle and flake, effectively inhibiting the corrosion formation and expansion of the exposed zinc layer. The composite coatings have good self-healing ability.
基金This work was supported by the Bengbu Yucheng New Materials Science and Technology Ltd. （No.2012QTXM0375） and the Natural Science Foundation of Anhui Province （No.1208085QE99）.
文摘Hydroxylamine sulfate （HAS） and sodium nitrite are used as the accelerators for zinc phos- phate coating on high carbon steel. Phase evolution of phosphate coating was investigated by X-ray diffraction. It is found that the phosphating coatings are mainly composed of hopeite Zn3Fe（PO4）2.4H2O and phosphophyllite Zn2Fe（PO4）2.4H2O. The microstructural changes of the phosphate coating, as a function of phosphating time, were evaluated by scanning elec- tron microscopy. Four-ball friction experiments reveal that hydroxylamine sulfate instead of sodium nitrite can effectively reduce the friction coefficient of lubricated phosphating coat- ing. Therefore, it may be expected that HAS will be widely used as a fast and ECO-friendly accelerator in phosphate industry.
基金Research Foundation of The Education Department of Liaoning Province,China(L2010396)Scientific Research Starting Foundation for the DoctorsShenyang University of Technology,China(2008-33)
文摘The corrosion behavior of a NdFeB magnet obtained at room temperature,with and without ultrasonic were investigated.The corrosion resistance was investigated by corrosion immersion tests in 3 wt%neutral NaCl solutions,potentiodynamic polarization tests and electrochemical impedance spectroscopy(EIS).The morphology of the conversion coatings on NdFeB surface were analyzed by scanning electron microscopy(SEM).And the forming mechanism of coatings was studied by potential-time curves.The tests of corrosion resistances show that the combination of phosphating treatment with ultrasonic will further improve the corrosion resistance of the NdFeB.The SEM also confirms that phosphating coating under ultrasonic is more homogeneous and compact.
基金the financial support from the Hunan Provincial Science and Technology Plan Project(Nos.2017TP1001,2020JJ4710)National Natural Science Foundation of China(No.11764018)+2 种基金the Natural Science Foundation of Jiangxi Province(No.20202ACBL211004)Changsha Science and Technology Plan(No.kq1801079)National Natural Science Foundation of China(No.21776317).
文摘Designing non-noble metal electrocatalysts toward alkaline hydrogen evolution reaction(HER)with high performance at a large current density is urgent.Herein,a CoO/CoP heterostructure catalyst(termed POZ)was designed by a phosphating strategy.The strong electron transfer on the interface of CoO/CoP was experimentally and theoretically proven.POZ showed a low overpotential of 236 mV at 400 mA/cm^(2),which was 249 mV lower than non-phosphated sample.It also exhibited a remarkable solar-to-hydrogen conversion efficiency of 10.5%.In this work,the construction of CoO/CoP interface realized by a simple phosphating strategy could provide an important reference to boost the HER performance on those materials not merely metal oxides.
基金supported by Fundamental Research Funds for Central Universities of SCUT(No.D2182400)Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(No.2016TQ03N541)+1 种基金Guangdong Natural Science Funds for Distinguished Young Scholar(No.2017B030306001)the National Natural Science Foundation of China(No.51972147)。
文摘Transition metal phosphide(TMP) based electrocatalysts possessing special crystal and electronic structures attract broad attention in the field of electrocatalysis.Immense effort is made to optimize TMP catalysts aiming to satisfy the electrochemical catalysis performance.In this work,an environmentally friendly in situ green phosphating strategy and spatial limiting effect of the RuCo precursor is employed to fabricate the ruthenium nanoclusters anchored on cobalt phosphide hollow microspheres(Ru NCs/Co_(2)P HMs).The obtained Ru NCs/Co_(2)P HMs electrocatalysts exhibit high hydrogen evolution reaction(HER) activity at wide pH ranges,which require an overpotential of 77 mV to achieve the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4) and 118 mV in 1.0 mol/L KOH.Besides,the multifunctional Ru NCs/Co_(2)P HMs exhibit good oxygen evolution reaction(OER) activity with an overpotential of 197 mV to reach the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4),which is below that of the commercial RuO_(2) electrocatalyst(248 mV).A two-electrode electrolyzer is assembled as well,in acid electrolyte,it achieves a current density of 10 mA/cm^(2) at a voltage of 1.53 V,which is superior to that of the benchmark of precious metal-based electrolyzer(1.58 V).
基金Project supported by the Henan Natural Science Foundation Program (200460178)
文摘Zinc phosphate coating formed on 6061-A1 alloy was studied with the help of electrochemical measurements, Fourier Transform Infrared （FTIR）, and Scanning Electron Microscopy （SEM）, after dipping it in phosphating solutions containing different concentrations of Rare Earth Nitrate （REN）. REN, which acted as an accelerator in the phosphating solution, could catalyze the surface reaction and accelerate the phosphating process. REN mainly enabled the P in the phosphate coating to exist in the form of PO4^3- and promoted the hydrolysis of phosphatic acid in a liquid layer at the cathodes. This resulted in the evolution of H2 at the cathodes, which increased the local pH value and in turn drove the precipitation of the phosphate coating. Additionally, REN was adsorbed on the surface of the aluminum substrates to form a gel during the phosphating process. These gel particles were good crystal seeds, which helped to form phosphate crystal nuclei and possess the function of a nucleation agent that could decrease the phosphate crystal size. The corrosion resistance of the formed zinc phosphate coatings was improved.
文摘To improve the corrosion resistance of phosphate coatings, the phosphated hot-dip galvanized (HDG) steel was post-sealed with cerium nitrate solution. The morphology, composition, corrosion resistance of the coatings was investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and neutral salt spray (NSS) tests. The results show that after post-sealing the phosphated HDG samples with cerium nitrate solution, the pores among the zinc phosphate crystals are sealed by the compounds containing phosphorus, oxygen and cerium; the zinc phosphate crystals are covered by the flocculent cerium compounds; and the continuous composite coatings are formed on HDG steel. The corrosion resistance of the composite coatings, which increases with the increase in phosphating time and cerium nitrate post-sealing time, is far higher than that of the single phosphate coatings. The composite coatings with the optimal corrosion resistance are obtained for phosphating 300 s and post-sealing 300 s; and the corrosion resistance is more outstanding than that of the chromate coatings.
基金Funded by the National Natural Science Foundation(No.501408517)the Natural Science Foundation of Fujian Province(No.2012J05099)the Pre-research Project of National Natural Science Fund of Xiamen University of Technology(No.XYK201410)
文摘The phosphated and cerium nitrate post-sealed galvanized steel was firstly scratched to expose zinc layer and then placed in neutral salt spray （NSS） chamber for different durations. The microstructure and compositions of the scratches were investigated using SEM and EDS. The phases of the corrosion products were examined through XRD. The self-healing mechanism of the composite coatings was discussed. The experimental results show that the composite coatings have an excellent corrosion resistance. The corrosion products increase with corrosion time and finally cover the whole scratch. They contain phosphorous, cerium, oxygen, chloride and zinc, and are fine needle and exceedingly compact. The composite coatings are favorable self-healing. During corrosion, the self-healing ions such as Ce3＋, Ce4＋, PO43-, Zn2＋ in the composite coatings were dissolved, migrated, recombined, and covered the exposed zinc, impeding zinc corrosion. The self-healing process of the scratches on the composite coatings can be divided into three stages, about 2 h, 4 h, and 24 h, respectively.
基金supported by the Natural Science Foundation of Henan Province (200510476009)
文摘Zinc phosphate coatings formed on 6061-Al alloy, after dipping in phosphating solutions containing different amounts of Y2O3（yttrium oxide）, were studied by scanning electron microscopy （SEM）, X-ray diffraction （XRD） and electrochemical measurements. Significant variations in the morphology and corrosion resistance afforded by zinc phosphate coating were especially observed as Y2O3 in phosphating solution varied from 0 to 40 mg/L. The addition of Y2O3 changed the initial potential of the interface between aluminum alloy substrate and phosphating solution and increased the number of nucleation sites. The phosphate coating thereby was less porous structure and covered the surface of aluminum alloy completely within short phosphating time. Phosphate coating was mainly composed of Zn3（PO4）2·4H2O （hopeite） and AlPO4（aluminum phosphate）. Y2O3, as an additive of phosphatization, accelerated precipitation and refined the gain size of phosphate coating. The corrosion resistance of zinc phosphate coating in 3% NaCl solution was improved as shown by polarization measurement. In the present research, the optimal amount of Y2O3 was 10-20 mg/L, and the optimal phosphating time was 600 s.
基金National Natural Science Foundation of China(52104294)Fundamental Research Funds for the Central Universities(FRF-TP-19-079A1)。
文摘The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion batteries.Lithium manganese iron phosphate(LiMn_(x)Fe_(1-x)PO_(4))has garnered significant attention as a promising positive electrode material for lithium-ion batteries due to its advantages of low cost,high safety,long cycle life,high voltage,good high-temperature performance,and high energy density.Although LiMn_(x)Fe_(1-x)PO_(4)has made significant breakthroughs in the past few decades,there are still facing great challenges in poor electronic conductivity and Li-ion diffusion,manganese dissolution affecting battery cycling performance,as well as low tap density.This review systematically summarizes the reaction mechanisms,various synthesis methods,and electrochemical properties of LiMn_(x)Fe_(1-x)PO_(4)to analyze reaction processes accurately and guide material preparation.Later,the main challenges currently faced are concluded,and the corresponding various modification strategies are discussed to enhance the reaction kinetics and electrochemical performance of LiMn_(x)Fe_(1-x)PO_(4),including multi-scale particle regulation,heteroatom doping,surface coating,as well as microscopic morphology design.Finally,in view of the current research challenges faced by intrinsic reaction processes,kinetics,and energy storage applications,the promising research directions are anticipated.More importantly,it is expected to provide key insights into the development of high-performance and stable LiMn_(x)Fe_(1-x)PO_(4)materials,to achieve practical energy storage requirements.
基金financially supported by the National Natural Science Foundation of China(Nos.82203680 and 52273278)the Natural Scientific Foundation of Liaoning Province(No.2021-MS-176)+1 种基金Shenyang Bureau of Science and Technology(No.RC230527)the Central Guidance Funding for Local Scientific and Techno-logical Development in Liaoning(No.2023JH6/100100029).
文摘Guided bone regeneration in the alveolar bone relies on the colonization and differentiation of immune cells within the defect area.The absence of osteoinductive and osteoimmune properties of currently available scaffolds hinders to achieve optimal repair outcomes in clinical settings.Thus,we aimed to enhance the bone repair ability of polycaprolactone(PCL)scaffolds by incorporating osteoinductive amorphous calcium phosphate(ACP)with immune-regulating zinc ions(ACP(Zn),ACZP),to create a favorable immunomodulatory microenvironment.After one day of co-culture with PCL-ACZP,the spreading area of macrophage cells was significantly higher than that from the original PCL scaffold.Additionally,over 32.1%of macrophages exhibited M2 polarization within three days of co-culture.The PCLACZP/macrophage-conditioned medium significantly boosted osteogenic gene expression in MC3T3-E1 cells.After eight weeks of implantation in a rat femoral condyle defect,the BV/TV from the PCL-ACZP group reached 32.9%,1.4 times of that from the PCL group.Furthermore,the PCL-ACZP-GelMA biphasic module as prepared successfully achieved complete regeneration of three-walled alveolar bone defects in rabbits,resulting in arch-shaped alveolar bone repair and providing greater convenience in the clinical settings.This study showcased the effectiveness of PCL-ACZP-GelMA biphasic module as bioactive scaffolds in the morphological restoration of alveolar bone.
基金support of the PID2021-124341OB-C22/AEI/10.13039/501100011033/FEDER,UE(MICIU)J.M.Vega also acknowledges the Grant RYC2021-034384-I funded by MICIU/AEI/10.13039/501100011033 and by“European Union Next Generation EU/PRTR”.
文摘In this study,a phosphate-based conversion coating(PCC)was applied as a precursor before forming silicate-fluoride(SiF)and silicate-phosphate-fluoride(SiPF)based flash-plasma electrolytic oxidation(Flash-PEO)coatings on AZ31B magnesium alloy.The main novelty is the successful incorporation of calcium,zinc,manganese and phosphate species into the Flash-PEO coatings via a precursor layer rather than using the electrolyte.The precursor also led to longer lasting and more intense discharges during the PEO process,resulting in increased pore size.Corrosion studies revealed similar short-term performance for all coatings,with impedance modulus at low frequencies above 10^(7)Ωcm^(2),and slightly better performance for the SiPF-based coating.Nonetheless,the enlarged pores in the PEO coatings functionalized with the PCC precursor compromised the effectiveness of self-healing mechanisms by creating diffusion pathways for corrosive species,leading to earlier failure.These phenomena were effectively monitored by recording the open circuit potential during immersion in 0.5 wt.%NaCl solution.In summary,this study demonstrates that conversion coatings are a viable option for the functionalization of PEO coatings on magnesium alloys,as they allow for the incorporation of cationic and other species.However,it is crucial to maintain a small pore size to facilitate effective blockage through self-healing mechanisms.
基金financially supported by the New Jersey Department of Environmental ProtectionUS EPA。
文摘In this study,synthetic wastewater containing 110μg/L arsenate(As(V)),0-20 mg/L fulvic acid(FA),and 0-12.3 mg/L phosphate was treated with 3 mg/L Fe3+.The mechanisms of FA and phosphate effects on As(V)removal by ferric chloride were determined using 0.22-10μm pore-size filtration,Zetasizer analysis,and in situ flow through cell ATR-FTIR.The results showed that up to 20mg/L FA had almost no effect on the solubility of ferric hydroxide precipitates and adsorption of As(V)by the precipitates.When FA concentration increased from 0 to 20 mg/L,the adsorption of FA led to higher negative zeta potential of the precipitates and the strong electrostatic repulsion between the precipitates decreased the particle size of ferric hydroxide flocs fromlarger than 10μmto smaller than 1μm.In the presence of 5-20 mg/L FA,46%-63%As(V)was adsorbed onto the flocs with particle size in the range of 0.45-1μm.On the other hand,phosphate did not affect the size of ferric hydroxide flocs and significantly increased the dissolved As(V)concentration because it competed with As(V)for adsorption sites on ferric hydroxide precipitates.The addition of 5mg/L cationic organic flocculant significantly reduced the effect of FA on As(V)removal,but did not reduce the effect of phosphate on As(V)removal.The findings of this study will help develop effective arsenic treatment techniques and predict the mobility of arsenic in the environment.
基金the Anusandhan National Research Foundation(ANRF),Science and Engineering Research Board(SERB),Department of Science&Technology,Government of India for a start-up research grant(M-14/0599,Sanction order no.SRG/2022/001478)Seed Grant under Institutions of Eminence(IoE),Banaras Hindu University(BHU)(Dev.Scheme No.6031)for financial assistance.
文摘The green energy transition relies heavily on critical metals,such as rare earth elements(REEs).However,their reserves are primarily focused in a few countries,such as China,which accounts for approximately 70%of global production.Hence,several countries are currently looking for alternative resources for REEs.Alternative REE resources in the supply chain include recycling of e-waste,industrial waste like red mud and phosphogypsum,coal ash,mine tailings,ocean floor sediments,and even certain types of sedimentary deposits like phosphorites where REEs are present in lower concentrations but at larger volumes compared to primary ore deposits which are becoming targets by REEs industry.Currently,several studies are going on the development of eco-friendly REEs extraction technologies from phosphorite deposits.Consequently,advanced data analysis tools,such as Machine Learning(ML),are becoming increasingly important in mineral prospectivity and are rapidly gaining traction in the earth sciences.Phosphorite deposits are mainly used to manufacture fertilizers as these rocks are known for their significant phosphorus content.Moreover,these formations are considered a prospective resource of REEs.The different types of phosphorite deposits such as continental,seamount,and ore deposits worldwide reported concentrations of∑REE upto 18,000µg/g.Due to the augmented claim of REEs for various ultra-modern,and green technology applications that are required to switch over to a carbon-neutral environment,these phosphorite deposits have become an important target mostly because of their relatively higher content of REEs especially heavy rare earth elements(HREE).For example,Mississippian phosphorites reported ∑ HREE 7,000µg/g.To have a comprehensive understanding of the REEs potential of these phosphorite deposits which also include several Chinese phosphorite deposits,this study is undertaken to review the phosphorite deposits in the world and their REEs potential,in addition to some of the associated aspects such as applications and formation mechanisms for different types of phosphorite deposits such as igneous phosphate deposits,sedimentary phosphorite deposits,marine phosphorite deposits,cave phosphate deposits,and insular guano deposits.Other important aspects include their occurrences,types,geochemical characteristics,the REEs enrichment mechanisms,and various recovery methods adopted to recover REEs from different phosphorite deposits.The present review paper concludes that the recent studies highlight the global potential of phosphorite deposits to satisfy the increasing demand for REEs.Extracting REEs from phosphorite presents no significant technological or environmental difficulties,as long as radioactive elements are eliminated.In India,more comprehensive geological surveys,along with the advancement of new methods and evaluations,are required to locate phosphorite deposits with high concentrations of REEs.
基金financed by the Spanish Ministry of Science and Innovation and the European Regional Development Fund(ERDF)(No.PID20211234690BI00)the European Joint Program EJP_Soil(TRACE-Soils)(No.862695)+1 种基金the Spanish Ministry of Science and Innovation(RED2018-102624TMCIN/AEI/10.13039/501100011033)the Project PREPSOIL European Union(No.101070045,HORIZON CSA)。
文摘Whilst phosphorus(P)in soil is considered to be abundant,the portion available for plant uptake constitutes less than 1%of the overall P present.To enhance crop productivity,the utilization of mineral P fertilizers has become pervasive in agriculture.Nonetheless,the escalating prices of chemical fertilizers,coupled with new European regulations prohibiting the use of P fertilizers containing cadmium,have highlighted the urgency to identify environmentally friendly products and practices for P fertilization in agricultural soils.This comprehensive review delves into the current landscape of P fertilization from agricultural,political,and economic standpoints.We recognize the potential of microbes in mobilizing P,but emphasize the necessity for more robust research to establish their effectiveness in promoting plant P uptake under real-world conditions.Additionally,we explore the role of agricultural conservation practices,such as optimal tillage,diversified cropping systems,and increased organic carbon input,in conserving P.Furthermore,this review contemplates forthcoming innovations in research.These innovations encompass the development of enhanced formulations for biofertilizers and the undertaking of more comprehensive studies within the realm of conservation agriculture.All these endeavors collectively hold the potential to augment P accessibility to plants in a sustainable manner,thereby advancing agricultural sustainability and productivity.
基金supported by Hebei Key Laboratory of Mineral Resources and Ecological Environment Monitoring(No.HBMREEM202302)Tianjin Key Research and Development Science and Technology Project(Nos.24YFXTHZ00170 and 24YFXTHZ00050)。
文摘The interaction mechanism between eggshell calcium and endogenous silica in biomass during biochar modification,and its impact on phosphate adsorption performance and slow-release fertilizer characteristics,remains unexplored.This study investigates that high silica content in biomass(>6%)inhibits the decomposition of CaCO_(3)in eggshells during pyrolysis,reducing the formation of active calcium species(CaO and Ca(OH)_(2)),while moderate silica levels(4%-5%)promote the formation of CaSiO_(3),enhancing phosphorus adsorption without hindering Ca^(2+)activation.Adsorption studies reveal that the precipitation of Ca_(5)(PO_(4))_(3)(OH)resulting from the combination of CaO and Ca(OH)_(2)with phosphate is the primary and effective form for phosphorus removal in calcium-modified adsorbents,accompanied by Ca_(3)(PO_(4))_(2)·2H_(2)O precipitation formed by CaSi O_(3).Eggshell calcium-modified corn straw biochar(ECS)exhibited the highest adsorption capacity,reaching 123.3 mg/g,outperforming materials in previous studies.ECS also demonstrated excellent pH adaptability and selective phosphate removal.As a biochar-based phosphorus fertilizer,ECS-P exhibits high phosphorus extractability in formic acid(93.92%)but low water solubility(0.62%),with phosphorus release during the seven-day intermittent leaching experiment remaining between 0.53 to 0.875 mg/L.These results confirm its potential as a phosphorus cycling fertilizer.This study provides fundamental insights into optimizing biomass selection based on silica content for calcium modification,offering an efficient strategy for both phosphate recovery and slow-release fertilizer development.
基金supported by the Chilwee Group(No.CWDY-ZH-YJY-202101-001)the Fundamental Research Funds for the Central Universities(No.2042023kf0214)the Starting Funding from Wuhan University.
文摘The efficient recycling of spent lithium iron phosphate(LiFePO_(4),also referred to as LFP)should convert Fe(Ⅱ)to Fe(Ⅲ),which is key to the extraction of Li and separation of Fe and is not well understood.Herein,we systematically study the oxidation of LiFePO_(4)in the air and in the solution containing oxidants such as H_(2)O_(2)and the effect of oxidation on the leaching behaviors of LFP.In the air,O_(2)breaks down the LFP olivine structure at 550℃for 1 h by oxidizing Fe(Ⅱ)to Fe(Ⅲ)in terms of converting LFP to Li_(3)Fe_(2)(PO_(4))_(3)and Fe_(2)O_(3).After that,Li is leached in 0.5 M sulfuric acid solution and is further recycled as Li_(3)PO_(4)with a Li recovery efficiency of 97.48%.Meanwhile,Fe is recovered as FePO_(4)and Fe_(2)O_(3).Compared with H_(2)SO_(4)-H_(2)O_(2),the air oxidation saves H_(2)O_(2)but increases the leaching efficiency of Fe and H_(2)SO_(4)consumption.The discrepancy of Fe leaching efficiency can be attributed to the different leaching mechanisms involving the solid-to-solid and solid-to-liquid-to-solid conversions.Furthermore,the results of the Everbatt model analysis show that the air roasting-H_(2)SO_(4)leaching method has low emission and potentially high income,which is simple and safe.Overall,this work will deepen the understanding of acid leaching of LFP and favorably stimulate the maturation of the LFP recycling technique.
基金supported by the National Natural Science Foundation of China(52127801)Postdoctoral Fellowship Program of CPSF under Grant Number GZC20231545,China Postdoctoral Science Foundation(2024T170557 and 2023M742224)+1 种基金Shanghai Post-doctoral Excellence Program(No.2023440)City University of Hong Kong Donation Grants(DON-RMG No.9229021 and 9220061).
文摘Pure Mg boasting a relatively small corrosion rate is a potential biodegradable metal material for implants.However,its degradation behavior in the complex physiological environment is still a lack of understanding.In this work,we investigated the effect of corrosion product film layers on the degradation behavior of pure Mg in physiological environments.Pure Mg shows a faster corrosion rate in simulated body fluid(SBF)compared to NaCl solution.Hydrogen evolution experiments indicate that the degradation rate of pure Mg in SBF decreases rapidly within the first 12 h but stabilizes afterward.The rapid deposition of low-solubility calcium phosphate on the pure Mg in SBF provides protection to the substrate,resulting in a gradual decrease in the degradation rates.Consequently,the corrosion product film of pure Mg formed in SBF exhibits a layered structure,with the upper layer consisting of dense Ca_(3)(PO_(4))_(2)/Mg_(3)(PO_(4))_(2) and the lower layer consisting of Mg(OH)_(2)/MgO.Electrochemical impedance spectroscopy(EIS)shows that the resistance of the corrosion product film increases over time,indicating gradual strengthening of the corrosion resistance.The 4-week degradation results in the femoral marrow cavity of mice are consistent with the result in SBF in vitro.
基金the support of this research by the National Natural Science Foundation of China (No. 22179034)the Natural Science Foundation of Heilongjiang Province (No. ZD2023B002)。
文摘Developing high-efficient and low-loading Pt based catalyst is significant for the electrocatalytic p Huniversal hydrogen evolution reaction(HER). Herein, the molybdenum carbide nanoparticles supported on the polyhedral N-doped carbon nanotube skeleton(Mo C/NCT) composite has been synthesized by a pyrolysis of polyacid organo-metallic phosphate framework precursor. Then, only 2.15 wt% Pt are loaded on the Mo C/NCT to form Pt-Mo C/NCT catalyst, which performs superior HER activity and stability in entire p H range. Specially, the overpotentials of 22 and 74 m V are respectively attained at 10 m A/cm^(2) in1.0 mol/L KOH and 0.5 mol/L H_(2)SO_(4) electrolytes, approaching or even exceeding commercial Pt/C. More importantly, it can be used as excellent catalyst for efficient hydrogen production at 0–14 p H range. Density functional theory(DFT) calculations demonstrate that the interaction between Mo C and Pt leads to the electron redistribution at the corresponding interfaces and the downward shift of the d-band centers, thus optimizing H*adsorption and desorption for promoting the HER activity. Besides, the unique three-dimensional network structure is conductive to the transmission of mass and electrons. In the application of both alkaline and acidic electrolysers, only 1.52 V voltage of solar panel can drive a hydrogen production current density of 10 m A/cm^(2).
