Efficient Indium Sulfide Photoelectrode with Crystal Phase and Morphology Control for High-Performance Photoelectrochemical Water Splitting

Crystal phase control of materials plays an important role on their properties in photocatalysis and photoelectrocatalysis. Herein, cubic and tetragonal phase control of In 2 S 3 photoanodes with various morphologies on indium tin oxide transparent conductive glass substrate have been successfully realized through a simple hydrothermal method for the first time. According to the detailed characterization analysis, we proposed a model to interpret the phase transition of In 2 S 3 along with hydrothermal reaction time. The photoelectrochemical tests suggest that the cubic phase In 2 S 3 nanocubes with cuneiform morphology exhibit a photocurrent density of 0.50 mA/cm 2 at 1.23 V vs RHE benefit by the special structure for efficient charge separation and transfer. This is the highest photocurrent values of single In 2 S 3 crystals best to our knowledge. Furthermore, the photoelectrochemical performance of In 2 S 3 can be greatly improved by depositing a Co–Pi cocatalysts layer. The composites show a 1.36-fold increase of photocurrent density (0.68 mA/cm 2 at 1.23 V vs RHE) compared to that of pristine In 2 S 3 . This work highlights that In 2 S 3 can be an attractive candidate as photoanodes for photoelectrochemical water splitting, and the crystal phase control presents a new avenues to the exploration and design of photoelectrodes for realizing superior performances.