Photoelectrochemical Hydrogen Generation with CdS−CuS/Reduced Ti−Ni−O Composite Photoanode

Efficient and stable photoanodes are essential for advancing sacrificial-assisted photoelectrochemical hydrogen generation toward sustainable hydrogen production. To address the wide band gap and rapid charge recombination of pristine TiO2, we designed a defect-engineered CdS−CuS/Reduced Ti−Ni−O composite photoanode. Ti−Ni−O nanotube arrays were fabricated via anodization and annealing, followed by chemical reduction with NaBH4 to introduce oxygen vacancies. Subsequently, a CdS layer and a CuS layer were sequentially deposited onto the nanotubes using the successive ionic layer adsorption and reaction (SILAR) method. The composite photoanode demonstrated highly efficient PEC performance for assisted hydrogen evolution, achieving a photocurrent density of 10.16 mA/cm2 at 0 V vs Ag/AgCl in a Na2S/Na2SO3 sacrificial electrolyte under simulated solar illumination. The remarkable PEC enhancement originated from the broadened visible-light absorption and efficient charge separation facilitated by the CdS−CuS p−n heterojunction combined with oxygen-vacancy-induced defect states. This work demonstrates an effective strategy for developing high-performance photoanodes through the synergistic integration of defect engineering and multi-component heterostructures for solar-to-chemical energy conversion.