Atomically-precise Janus polyoxometalate catalyst with tunable water splitting activity

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, reported polyoxometalate (POM)-based often contain only single type transition metal substitution driving either production or evolution. Herein, viable two-step parental approach developed to synthesize two structurally-new mixed-transition-metal-substituted polyoxometalates (mixed TMSPs), K6Na4[Mn2Ni2(H2O)2(PW9O34)2]·21H2O ({Mn2Ni2}) K10[Mn2Co2-(H2O)2(PW9O34)2]·35H2O ({Mn2Co2}), using Na12[Mn2Na2(PW9O34)2]·36H2O ({Mn2Na2}) the precursor. Characterization results confirmed nearly quantitative Na+ with Ni2+ Co2+ ions. X-ray absorption fine structure (XAFS) spectroscopy revealed that Mn atoms are preferentially located in internal positions central belt while Ni Co reside external, solvent-accessible positions. Benefiting from second catalytically active metals, resulting {Mn2Ni2} {Mn2Co2} can be utilized Janus towards H2 O2 under visible light irradiation greatly-enhanced activity compared {Mn2Na2}. introduction mixed metals into POM structures not enriches POMs family, also provides an effective strategy control electronic catalytic properties POM-based at atomic level.