Synergistic effect of atomic layer deposition-assisted cocatalyst and crystal facet engineering in SnS2 nanosheet for solar water oxidation
Abstract
The heat treatment process for adjusting the exposed crystal facets, forming a high-quality interface, and building an efficient cocatalyst on the surface of the SnS2.The severe bulk recombination and sluggish oxygen evolution reaction (OER) dynamics of photoanodes severely restrict the application of photoelectrochemical (PEC) devices. To solve these two problems, crystallographic facet orientation and cocatalyst emergence with a high-quality photoanode/cocatalyst interface were realized through an air annealing-assisted strategy to treat atomic layer deposition (ALD)-modified SnS2 nanosheet arrays. Based on experimental observations and theoretical calculations, the reduced (001) crystal facet of SnS2 decreases the recombination of photogenerated carriers in the bulk and improves the carrier separation of the photoanode. Moreover, the unexpectedly formed ZnTiOxSy film decreases the overpotential of the surface OER, reduces interface recombination, and extends the carrier lifetime. These synergistic effects lead to significantly enhanced PEC performance, with a high photocurrent density of 1.97 mA cm−2 at 1.23 V vs. reversible hydrogen electrode (RHE) and a low onset potential of 0.21 V vs. RHE, which are superior to reported mostly SnS2-based photoanodes.
