High-Density Two-Dimensional SnS2 Nanoflake Array on Carbon Paper for Effective Photoelectrochemical Water Splitting br

Photoelectrochemical water splitting is a promising strategy to harvest energy from the sun; it utilizes a photoactive material, coupled with a slight electrical input, to convert water into hydrogen and oxygen. These generated gases are stored as chemical energy and can later be used as fuels. Among many reported photoactive materials, tin disulfide (SnS2)offers unique advantages due to the earth abundance of tin and its appropriate bandgap. Here, we report the fabrication of high-density two-dimensional vertically aligned SnS2nanoflakesanchored on a conductive substrate for photoelectrochemical water splittingapplication. The as-fabricated nanoflakes were carefully studied, where crystalline,hexagonal SnS2flakes can clearly be observed; their crystal structure has beenindexed with the assistance of high-resolution transmission electron microscopy.For photoelectrochemical testing, a Solartron potentiostat was used to perform theindicative electrochemistry tests, including linear polarization, electrochemicalimpedance spectroscopy, and potential static with a light on-offcurrent. A HoribaHal-320 solar simulator was used as a light source to illuminate the active samples placed in a 0.5 M Na3PO4aqueous electrolyte.The incident photon to converted electronfigure was also calculated and was found to have 2.66% efficiency at zero bias (i.e.,spontaneous evolution reaction) and 20.53% efficiency at 1 V bias. This high efficiency is probably due to both the high optical gapof similar to 2.4 eV obtained from these 2D nanostructures and their physical structure that maximizes light trapping of the incident source.