A Si Photocathode Protected and Activated with a Ti and Ni Composite Film for Solar Hydrogen Production

An efficient, stable and scalable hybrid photoelectrode for visible-light-driven H(2) generation in an aqueous pH 9.2 electrolyte solution is reported. The photocathode consists of a p-type Si substrate layered with a Ti and Ni-containing composite film, which acts as both a protection and electrocatalyst layer on the Si substrate. The film is prepared by the simple drop casting of the molecular single-source precursor, [{Ti(2)(OEt)(9)(NiCl)}(2)] (TiNi(pre)), onto the p-Si surface at room temperature, followed by cathodic in situ activation to form the catalytically active TiNi film (TiNi(cat)). The p-Si|TiNi(cat) photocathode exhibits prolonged hydrogen generation with a stable photocurrent of approximately −5 mA cm(−2) at 0 V vs. RHE in an aqueous pH 9.2 borate solution for several hours, and serves as a benchmark non-noble photocathode for solar H(2) evolution that operates efficiently under neutral–alkaline conditions.