Co_(3)O_(4) is a promising catalyst for the chlorine evolution reaction(CER)in seawater;however,its CER selectivity is compromised by the adsorption of the competitive oxygen evolution reaction intermediate(OH^(-))at ...Co_(3)O_(4) is a promising catalyst for the chlorine evolution reaction(CER)in seawater;however,its CER selectivity is compromised by the adsorption of the competitive oxygen evolution reaction intermediate(OH^(-))at Co sites.Inspired by the hard-soft acid-base(HSAB)theory,this study proposes incorporating early transition metal sites(V)with a low degree of electron delocalization into Co_(3)O_(4) to modulate the selective adsorption of reactants on catalytic sites.Experimental and theoretical calculations reveal that V incorporation facilitates the electron accumulation at the Co site,significantly strengthening the interaction between Co and Cl^(-).Meanwhile,the loss of electrons from V sites generates a more localized electronic state that preferentially adsorbs OH^(-),thus reducing the Co-OH interaction and releasing more Co sites for Cl^(-)adsorption.Therefore,Co_(2)VO_(4) exhibits a high CER selectivity of 92.3%and maintains one of the highest stabilities over 300 h in natural seawater.The resulting half-flow cell achieves~100%disinfection efficiency in seawater,validating the HSAB theory-based design strategy and offering new guidance for developing highly selective seawater CER catalysts.展开更多
Heterogeneous crystallization is a common occurrence during the formation of solidwastes.It leads to the encapsulation of valuable/hazardous metals within the primary phase,presenting significant challenges for waste ...Heterogeneous crystallization is a common occurrence during the formation of solidwastes.It leads to the encapsulation of valuable/hazardous metals within the primary phase,presenting significant challenges for waste treatment andmetal recovery.Herein,we proposed a novel method involving the in-situ formation of a competitive substrate during the precipitation of jarosite waste,which is an essential process for removing iron in zinc hydrometallurgy.We observed that the in-situ-formed competitive substrate effectively inhibits the heterogeneous crystallization of jarosite on the surface of anglesite,a lead-rich phase present in the jarositewaste.As a result,the iron content on the anglesite surface decreases from34.8%to 1.65%.The competitive substrate was identified as schwertmannite,characterized by its loose structure and large surface area.Furthermore,we have elucidated a novel mechanism underlying this inhibition of heterogeneous crystallization,which involves the local supersaturation of jarosite caused by the release of ferric and sulfate ions from the competitive substrate.The local supersaturation promotes the preferential heterogeneous crystallization of jarosite on the competitive substrate.Interestingly,during the formation of jarosite,the competitive substrate gradually vanished through a dissolution-recrystallization process following the Ostwald rule,where a metastable phase slowly transitions to a stable phase.This effectively precluded the introduction of impurities and reduced waste volume.The goal of this study is to provide fresh insights into the mechanism of heterogeneous crystallization control,and to offer practical crystallization strategies conducive to metal separation and recovery from solid waste in industries.展开更多
基金supported by the Guangxi Science and Technology Program(2023AB38061)the National Natural Science Foundation of China(22162004,22479031)the High-performance Computing Platform of Guangxi University。
文摘Co_(3)O_(4) is a promising catalyst for the chlorine evolution reaction(CER)in seawater;however,its CER selectivity is compromised by the adsorption of the competitive oxygen evolution reaction intermediate(OH^(-))at Co sites.Inspired by the hard-soft acid-base(HSAB)theory,this study proposes incorporating early transition metal sites(V)with a low degree of electron delocalization into Co_(3)O_(4) to modulate the selective adsorption of reactants on catalytic sites.Experimental and theoretical calculations reveal that V incorporation facilitates the electron accumulation at the Co site,significantly strengthening the interaction between Co and Cl^(-).Meanwhile,the loss of electrons from V sites generates a more localized electronic state that preferentially adsorbs OH^(-),thus reducing the Co-OH interaction and releasing more Co sites for Cl^(-)adsorption.Therefore,Co_(2)VO_(4) exhibits a high CER selectivity of 92.3%and maintains one of the highest stabilities over 300 h in natural seawater.The resulting half-flow cell achieves~100%disinfection efficiency in seawater,validating the HSAB theory-based design strategy and offering new guidance for developing highly selective seawater CER catalysts.
基金supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.52121004)the Major Program Natural Science Foundation of Hunan Province of China(No.2021JC0001)+2 种基金the National Key R&D Programof China(No.2022YFC3900200)the National Natural Science Foundation of China(No.22276218)the Science and Technology Innovation Programof Hunan Province(No.2021RC3013).
文摘Heterogeneous crystallization is a common occurrence during the formation of solidwastes.It leads to the encapsulation of valuable/hazardous metals within the primary phase,presenting significant challenges for waste treatment andmetal recovery.Herein,we proposed a novel method involving the in-situ formation of a competitive substrate during the precipitation of jarosite waste,which is an essential process for removing iron in zinc hydrometallurgy.We observed that the in-situ-formed competitive substrate effectively inhibits the heterogeneous crystallization of jarosite on the surface of anglesite,a lead-rich phase present in the jarositewaste.As a result,the iron content on the anglesite surface decreases from34.8%to 1.65%.The competitive substrate was identified as schwertmannite,characterized by its loose structure and large surface area.Furthermore,we have elucidated a novel mechanism underlying this inhibition of heterogeneous crystallization,which involves the local supersaturation of jarosite caused by the release of ferric and sulfate ions from the competitive substrate.The local supersaturation promotes the preferential heterogeneous crystallization of jarosite on the competitive substrate.Interestingly,during the formation of jarosite,the competitive substrate gradually vanished through a dissolution-recrystallization process following the Ostwald rule,where a metastable phase slowly transitions to a stable phase.This effectively precluded the introduction of impurities and reduced waste volume.The goal of this study is to provide fresh insights into the mechanism of heterogeneous crystallization control,and to offer practical crystallization strategies conducive to metal separation and recovery from solid waste in industries.
