Atomically-precise Janus polyoxometalate catalyst with tunable water splitting activity  

作　　者：Zhimin Wang Xing Xin Zheng Li Mo Zhang Jiangwei Zhang Yeqin Feng Junhao Zhang Hongjin Lv Guo-Yu Yang 

机构地区：[1]MOE Key Laboratory of Cluster Science,Beijing Key Laboratory of Photoelectroic/Electrophotonic Conversion Materials,School of Chemistry and Chemical Engineering,Beijing Institute of Technology,Beijing 102488,China [2]College of Chemistry and Chemical Engineering,Inner Mongolia University,Hohhot 010021,China

出　　处：《Science China Chemistry》2023年第6期1771-1780,共10页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(21871025,21831001,21701168);the Recruitment Program of Global Experts(Young Talents);BIT Excellent Young Scholars Research Fund;the National Key R&D Program of China(2020YFA0406101)。

摘　　要：The development of bifunctional catalysts for solar-driven hydrogen and oxygen evolution has been regarded as a challenging but interesting research topic.As promising multi-electron-transfer catalysts,previously reported polyoxometalate(POM)-based catalysts often contain only a single type of transition metal substitution for driving either hydrogen production or oxygen evolution.Herein,a viable two-step parental substitution approach has been developed to synthesize two structurally-new mixed-transition-metal-substituted polyoxometalates(mixed TMSPs),K_(6)Na_(4)[Mn_(2)Ni_(2)(H_(2)O)2(PW_(9)O_(34))2]·21H_(2)O({Mn_(2)Ni_(2)})and K10[Mn_(2)Co_(2)(H_(2)O)2(PW_(9)O_(34))2]·35H_(2)O({Mn_(2)Co_(2)}),using Na_(12)[Mn_(2)Na_(2)(PW_(9)O_(34))2]·36H_(2)O({Mn_(2)Na_(2)})as the precursor.Characterization results confirmed the nearly quantitative substitution of Na+with Ni_(2)+and Co_(2+)ions.X-ray absorption fine structure(XAFS)spectroscopy revealed that the Mn atoms are preferentially located in the internal positions of the central belt while Ni and Co atoms preferentially reside in the external,solvent-accessible positions.Benefiting from the second substitution of catalytically active transition metals,the resulting{Mn_(2)Ni_(2)}and{Mn_(2)Co_(2)}can be utilized as Janus catalysts towards H_(2) evolution and O_(2) evolution under visible light irradiation with greatly-enhanced activity compared to that of parental{Mn_(2)Na_(2)}.The introduction of mixed transition metals into POM structures not only enriches the POMs family,but also provides an effective strategy to control electronic structures and catalytic properties of POM-based catalysts at the atomic level.

关 键 词：Janus polyoxometalate catalyst mixed-transition-metal substitution X-ray absorption fine structure(XAFS) H EVOLUTION O EVOLUTION 

分 类 号：TQ116.2[化学工程—无机化工] TQ426