Enhanced Overall Water Splitting by a Zirconium‐Doped TaON‐Based Photocatalyst

Abstract Solar‐powered one‐step‐excitation overall water splitting (OWS) using semiconducting materials is a simple means of achieving scalable and sustainable hydrogen production. While tantalum oxynitride (TaON) is one of the few photocatalysts capable of promoting OWS via single‐step visible‐light excitation, the efficiency of this process remains extremely poor. The present work employed 15 nm amorphous Ta 2 O 5 ⋅3.3 H 2 O nanoparticles as a new precursor together with Zr doping and an optimized nitridation duration to synthesize a TaON‐based photocatalyst with reduced particle sizes and low defect densities. Upon loading with Ru/Cr 2 O 3 /IrO 2 cocatalysts, this material exhibited stoichiometric water splitting into hydrogen and oxygen, with an order of magnitude improvement in efficiency. Our findings demonstrate the importance of inventing/selecting the appropriate synthetic precursor and of defect control for fabricating active OWS photocatalysts.