摘要
Enabling Si photoanodes for efficient solar water oxidation would facilitate the development of solar fuel conversion, but it is challenging owing to Si surface passivation via photo-induced corrosion in aqueous electrolytes. To overcome this challenge, most approaches have focused on improving the stability of Si by coating dense and thin protective layers using high vacuum-based techniques such as atomic layer deposition. However, these procedures are costly, making scalability for practical applications difficult. Herein, we report a modified electroless deposition （ELD） method to uniformly deposit protective and catalytic Ni films on Si wafers, resulting in efficient and stable Si photoanodes for solar water oxidation. The optimized Ni/n-Si photoanode achieves an onset potential of -1.09 V vs. a reversible hydrogen electrode and a saturation current density of -27.5 mA/cm^2 under AM 1.5 G illumination at pH 14. The ELD method is additionally capable of Ni deposition on a 4-inch n-Si wafer, demonstrating the first 4-inch Si photoanode. The solar water oxidation of the ELD-Ni/n-Si photoanode can be further improved by surface texturing, built-in n-p junctions, or coupling with more efficient catalysts.
Enabling Si photoanodes for efficient solar water oxidation would facilitate the development of solar fuel conversion, but it is challenging owing to Si surface passivation via photo-induced corrosion in aqueous electrolytes. To overcome this challenge, most approaches have focused on improving the stability of Si by coating dense and thin protective layers using high vacuum-based techniques such as atomic layer deposition. However, these procedures are costly, making scalability for practical applications difficult. Herein, we report a modified electroless deposition （ELD） method to uniformly deposit protective and catalytic Ni films on Si wafers, resulting in efficient and stable Si photoanodes for solar water oxidation. The optimized Ni/n-Si photoanode achieves an onset potential of -1.09 V vs. a reversible hydrogen electrode and a saturation current density of -27.5 mA/cm^2 under AM 1.5 G illumination at pH 14. The ELD method is additionally capable of Ni deposition on a 4-inch n-Si wafer, demonstrating the first 4-inch Si photoanode. The solar water oxidation of the ELD-Ni/n-Si photoanode can be further improved by surface texturing, built-in n-p junctions, or coupling with more efficient catalysts.
