Enabling silicon photoanodes for efficient solar water splitting by electroless-deposited nickel

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-Si photoanode achieves an onset potential of ～ 1.09 V vs.a reversible hydrogen electrode and a saturation current density of ～ 27.5 mA/cm2 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-Si photoanode can be further improved by surface texturing,built-in n-p junctions,or coupling with more efficient catalysts.