Optimizing the microdynamics in alkaline and neutral conditions is a significant but challenging task in developing pH-universal hydrogen evolution(HER)electrocatalysts.Herein,a unique Pt-O-Ni bridge has been construc...Optimizing the microdynamics in alkaline and neutral conditions is a significant but challenging task in developing pH-universal hydrogen evolution(HER)electrocatalysts.Herein,a unique Pt-O-Ni bridge has been constructed to alter the coordination and electronic environment between Pt nanoparticles(Pt_n)and nickel metaphosphate(NPO)substrate(Pt-NPO).Sufficient electron transfer from NPO to Pt_n to maintain an electron-rich environment and a low valence state of Pt_n.Furthermore,H*is produced from the H_(2)O dissociation on Ni site and then spillover toward Pt sites to bind into H_(2),which makes up for the insufficient H_(2)O dissociation ability of Pt in Volmer step.Pt-NPO exhibits long-term stability and only need the overpotentials of 22.3,33.0 and 30.5 mV to attain 10 mA cm^(-2)in alkaline,neutral and acidic media,respectively.The anion-exchange membrane(AEM)water electrolyzer catalyzed by Pt-NPO shows high water electrolysis performance that a cell voltage of 1.73 V is needed to obtain the current density of500 mA cm^(-2)in 1 M KOH at 80℃,at the same time maintains good stability for 350 h.The regulation strategy proposed in this work is helpful for the design and synthesis of highly efficient pH-universal HER electrocatalysts.展开更多
Developing efficient pH-universal hydrogen evolution reaction(HER)catalysts is critical in the field of water electrolysis,however,which is severely hampered by the sluggish kinetics in alkaline media.Herein,a rutheni...Developing efficient pH-universal hydrogen evolution reaction(HER)catalysts is critical in the field of water electrolysis,however,which is severely hampered by the sluggish kinetics in alkaline media.Herein,a ruthenium(Ru)incorporation induced vacancy engineering strategy is firstly proposed to precisely construct oxygen vacancy(V_(O))-riched cobalt-ruthenium metaphosphate(CRPO)for high-efficiency pH-universal HER.The V_(O) modifies the electronic structure,improves the superficial hydrophilic and gas spillover capacity,it also reduces the coordination number of Ru atoms and regulates the coordination environment.Theoretical calculations indicate that Ru tends to adsorb H_(2)O and H^(*),whereas V_(O) tends to adsorb OH^(-),which greatly promotes the H_(2)O adsorption and the dissociation of HO-H bond.Ultimately,CRPO-2 exhibits remarkable HER performance,the mass activity is about 18.34,21.73,and 38.07 times higher than that of Pt/C in acidic,neutral,and alkaline media,respectively,at the same time maintain excellent stability.Our findings may pave a new avenue for the rational design of electrocatalysts toward pH-universal water electrolysis.展开更多
Salicylaldehyde Schiff base is a kind of important photochromism system,whose photochromism process is widely acknowledged to be co-determined by the electronic structure and molecular conformation.Normally,salicylald...Salicylaldehyde Schiff base is a kind of important photochromism system,whose photochromism process is widely acknowledged to be co-determined by the electronic structure and molecular conformation.Normally,salicylaldehyde Schiff base derivatives withα-type structures tend to exhibit photochromism while those withβ-type structures tend to be photostable.However,more and more counterexamples are found,and the root cause of photochromism property of salicylaldehyde Schiff base is still unclear.In this work,a series of chiral salicylaldehyde Schiff bases and their racemates were prepared.The formers are photochromic while the latters are photostable.Influenced by Wallach's rule,the homochiral counterparts have looser packing modes than that of the racemic counterparts.Mechanism study revealed that the pressure should be the root cause of photochromism property.Close molecule packing can restrict the photochromism property effectively after being pressed,which also explains why the photochromism of salicylaldehyde Schiff base is usually observed in solid state.This work not only reports the unique photo-responsive difference between the chiral salicylaldehyde Schiff bases and their racemates,more importantly,provides a new perspective to understand the influence of molecule pressure on their photophysical properties.展开更多
基金supported by the National Natural Science Foundation of China(22202080,22034006 and 22393930)Jilin Talent Development Foundation(E41S2001)the National Key Research and Development Program of China(2022YFF0710000).
文摘Optimizing the microdynamics in alkaline and neutral conditions is a significant but challenging task in developing pH-universal hydrogen evolution(HER)electrocatalysts.Herein,a unique Pt-O-Ni bridge has been constructed to alter the coordination and electronic environment between Pt nanoparticles(Pt_n)and nickel metaphosphate(NPO)substrate(Pt-NPO).Sufficient electron transfer from NPO to Pt_n to maintain an electron-rich environment and a low valence state of Pt_n.Furthermore,H*is produced from the H_(2)O dissociation on Ni site and then spillover toward Pt sites to bind into H_(2),which makes up for the insufficient H_(2)O dissociation ability of Pt in Volmer step.Pt-NPO exhibits long-term stability and only need the overpotentials of 22.3,33.0 and 30.5 mV to attain 10 mA cm^(-2)in alkaline,neutral and acidic media,respectively.The anion-exchange membrane(AEM)water electrolyzer catalyzed by Pt-NPO shows high water electrolysis performance that a cell voltage of 1.73 V is needed to obtain the current density of500 mA cm^(-2)in 1 M KOH at 80℃,at the same time maintains good stability for 350 h.The regulation strategy proposed in this work is helpful for the design and synthesis of highly efficient pH-universal HER electrocatalysts.
基金supported by National Natural Science Foundation of China(Nos.21721003,22202080,22034006).
文摘Developing efficient pH-universal hydrogen evolution reaction(HER)catalysts is critical in the field of water electrolysis,however,which is severely hampered by the sluggish kinetics in alkaline media.Herein,a ruthenium(Ru)incorporation induced vacancy engineering strategy is firstly proposed to precisely construct oxygen vacancy(V_(O))-riched cobalt-ruthenium metaphosphate(CRPO)for high-efficiency pH-universal HER.The V_(O) modifies the electronic structure,improves the superficial hydrophilic and gas spillover capacity,it also reduces the coordination number of Ru atoms and regulates the coordination environment.Theoretical calculations indicate that Ru tends to adsorb H_(2)O and H^(*),whereas V_(O) tends to adsorb OH^(-),which greatly promotes the H_(2)O adsorption and the dissociation of HO-H bond.Ultimately,CRPO-2 exhibits remarkable HER performance,the mass activity is about 18.34,21.73,and 38.07 times higher than that of Pt/C in acidic,neutral,and alkaline media,respectively,at the same time maintain excellent stability.Our findings may pave a new avenue for the rational design of electrocatalysts toward pH-universal water electrolysis.
基金supported by the National Natural Science Foundation of China(22371264,U1904172)the Excellent Young Scientist Foundation of Henan Province(202300410374)+4 种基金program for Science&Technology Innovation Talents in Universities of Henan Province(22HASTIT002)the Young-backbone Teacher Foundation of Colleges and Universities of Henan Province(2023GGJS062)the Natural Science Project of Zhengzhou Science and Technology Bureau(22ZZRDZX11)the Undergraduate Innovation and Entrepreneurship Training Program(202410463044)This study was supported by Center of Advanced Analysis&Gene Sequencing,Zhengzhou University.
文摘Salicylaldehyde Schiff base is a kind of important photochromism system,whose photochromism process is widely acknowledged to be co-determined by the electronic structure and molecular conformation.Normally,salicylaldehyde Schiff base derivatives withα-type structures tend to exhibit photochromism while those withβ-type structures tend to be photostable.However,more and more counterexamples are found,and the root cause of photochromism property of salicylaldehyde Schiff base is still unclear.In this work,a series of chiral salicylaldehyde Schiff bases and their racemates were prepared.The formers are photochromic while the latters are photostable.Influenced by Wallach's rule,the homochiral counterparts have looser packing modes than that of the racemic counterparts.Mechanism study revealed that the pressure should be the root cause of photochromism property.Close molecule packing can restrict the photochromism property effectively after being pressed,which also explains why the photochromism of salicylaldehyde Schiff base is usually observed in solid state.This work not only reports the unique photo-responsive difference between the chiral salicylaldehyde Schiff bases and their racemates,more importantly,provides a new perspective to understand the influence of molecule pressure on their photophysical properties.
