The Au nanoparticle-induced localized surface plasmon resonance effect and synergistic catalytic sites in Au/Co3O4/Si pyramid arrays for photoelectrochemical hydrogen evolution

Abstract

Photoelectrochemical (PEC) water decomposition is an efficient, cost-effective, and sustainable approach for hydrogen evolution utilizing solar energy and water. Among the various semiconductor materials, modified p-Si is widely regarded as the most suitable candidate for achieving efficient photocathodes in solar-powered PEC hydrogen evolution. In this study, silicon pyramid arrays (n⁺-p Si) were synthesized by means of structural modification, resulting in enhanced light absorption and conductivity. Subsequently, a metal–metal oxide support, the Si/Co₃O₄/Au, was synthesized on the surface of Si using simple electrodeposition and followed by a hydrogen reduction method. The distinctive localized surface plasmon resonance (LSPR) effect exhibited by Au, along with the synergistic interaction between Au and carrier materials, enhances the efficient transport of charges and improves the separation of photogenerated electrons and holes. In 17 hours, the Si/Co₃O₄/Au exhibited high catalytic activity and excellent stability. The photocurrent density at 0 V (vs. reversible hydrogen electrode (RHE)) could reach −38.5 mA cm⁻², and the rate of hydrogen evolution was approximately 14.28 μmol min⁻¹ cm⁻² under AM 1.5G simulated solar radiation. This study presents a promising approach for the rational design of a highly efficient Si-based photocathode.