Transient Behavior of Ni@NiO_<i>x</i> Functionalized SrTiO₃ in Overall Water Splitting

Abstract

High Resolution Image Download MS PowerPoint Slide Transients in the composition of Ni@NiO x core–shell co-catalysts deposited on SrTiO 3 are discussed on the basis of state-of-the-art continuous analysis of photocatalytic water splitting, and post-XPS and TEM analyses. The formation of excessive hydrogen (H 2:O 2 ≫ 2) in the initial stages of illumination demonstrates oxidation of Ni(OH) 2 to NiOOH (nickel oxyhydroxide), with the latter catalyzing water oxidation. A disproportionation reaction of Ni and NiOOH, yielding Ni(OH) 2 with residual embedded Ni, occurs when illumination is discontinued, which explains repetitive transients in (excess) hydrogen and oxygen formation when illumination is reinitiated.