Activating Kläui-Type Organometallic Precursors at Metal Oxide Surfaces for Enhanced Solar Water Oxidation

Activating molecular catalysts at the surface of metal oxides can be a promising strategy to overcome the sluggish interfacial kinetics and enhance the efficiencies for photo(electro)chemical (PEC) water oxidation. However, the physical association between inorganic semiconductors for PEC process and organometallic molecular catalysts for surface catalytic reactions generally remains a challenging problem. In the present work, Kläui-type organometallic precursor [Cp*Ir{P(O)(OH)2}3]Na was first synthesized and subsequently successfully anchored onto BiVO4 nanopyramids grown on transparent conducting substrates through various procedures. Treating the resulting hybrid heteronanostructure with IO4– induces a strong synergism between iridium atoms and BiVO4 nanocrystals that exhibits a 5.5 times enhancement in photocurrent density at 1.23 V vs reversible hydrogen electrode (RHE) for PEC water oxidation. This simple approach provides an effective alternative pathway for molecular catalysts anchoring on inorganic semiconductors for efficient renewable energy utilization.