Evidence for tetranuclear bis-μ-oxo cubane species in molecular iridium-based water oxidation catalysts from XAS analysis.

The structure of a highly active pyridine-alkoxide iridium water oxidation catalyst (WOC) is examined by X-ray absorption spectroscopy (XAS). A detailed comparison with IrO2 points to a rigid molecular unit of low nuclearity, with the best analysis suggesting a novel tetrameric iridium-oxo cubane as the resting state.

Graphite-protected CsPbBr perovskite photoanodes functionalised with water oxidation catalyst for oxygen evolution in water.

Metal-halide perovskites have been widely investigated in the photovoltaic sector due to their promising optoelectronic properties and inexpensive fabrication techniques based on solution processing. Here we report the development of inorganic CsPbBr-based photoanodes for direct photoelectrochemical oxygen evolution from aqueous electrolytes. We use a commercial thermal graphite sheet and a mesoporous carbon scaffold to encapsulate CsPbBr as an inexpensive and efficient protection strategy.

Electrochemical and Kinetic Insights into Molecular Water Oxidation Catalysts Derived from Cp*Ir(pyridine-alkoxide) Complexes.

We report the solution-phase electrochemistry of seven half-sandwich iridium(III) complexes with varying pyridine-alkoxide ligands to quantify electronic ligand effects that translate to their activity in catalytic water oxidation. Our results unify some previously reported electrochemical data of Cp*Ir complexes by showing how the solution speciation determines the electrochemical response: cationic complexes show over 1 V higher redox potentials that their neutral forms in a distinct demonstration of charge accumulation effects relevant to water oxidation. Building on previous work that analysed the activation behaviour of our pyalk-ligated Cp*Ir complexes -, we assess their catalytic oxygen evolution activity with sodium periodate (NaIO) and ceric ammonium nitrate (CAN) in water and aqueous BuOH solution.