1.7 eV Bandgap InGaN Nanorods Enabling High-Efficiency Photoelectrochemical Water Splitting

In a two-photon photoelectrochemical (PEC) series device with high theoretical efficiency, the optimal configuration of the anode necessitates a wide bandgap of 1.7 eV. We developed a parameter-optimized halide chemical vapor deposition (HCVD) method to successfully grow InGaN nanostructures with 1.7 eV bandgap for the first time. On this basis, InGaN/CuBi2O4/NiFeCoOx photoanodes were prepared using electrodeposition and immersion methods for efficient solar water oxidation. The optimized photoanode exhibited a low initial potential of 0.44 V vs reversible hydrogen electrode (RHE), achieving a photocurrent density of 8.6 mA/cm2 at the standard water oxidation potential (1.23 V vs RHE). To date, this is the highest value of HCVD-produced InGaN-based photoanodes, which could create a precondition for achieving highly efficient two-photon series electrode systems.