Nanostructured Electrodes Based on Two-Dimensional SnO₂ for Photoelectrochemical Water Splitting

Here we demonstrate the fabrication of two-dimensional SnO2 nanosheet arrays and their use as electrodes for solar water oxidation. These nanosheets deposited on commercial transparent electrodes are used as substrates for the deposition of photoactive semiconductors including BiVO4 and Fe2O3. These composite photoanodes show a marked enhancement in their photoelectrochemical (PEC) performance, including improved light absorption, lower onset potentials, and higher photocurrents. Importantly, SnO2 nanosheets alone have negligible PEC activity, suggesting that their role is purely morphological (enhanced surface area) and electronic (surface passivation, improved charge extraction). Our results provide the foundation for further work on photoanode architectures for efficient water splitting.