Noble-metal-free NiSnxOy decorated graphene cocatalyst for highly efficient reduction of water to hydrogen

• NiSnxOy/G was prepared by in-situ chemical deposition method.
• NiSnxOy/G exhibited higher photocatalytic hydrogen evolution activity than Ni/G.
• The highest apparent quantum efficiency (AQE) of EY-NiSnxOy/G was 36.2% at 430 nm.

Nickel tin composite oxides decorated graphene nanohybrid (NiSnxOy/G) cocatalyst was synthesized by in-situ chemical deposition and followed photoreduction reaction. The structure of NiSnxOy/G was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of NiSnxOy/G sensitized by Eosin Y (EY) for hydrogen evolution were evaluated under visible light irradiation (λ ＞ 420 nm) using triethanolamine (TEOA) as sacrificial donor. The results indicated that the large amounts of NiSnxOy adhered on the surface of graphene sheet as active sites for hydrogen production. NiSnxOy/G showed higher photocatalytic performance than Ni/G under visible light irradiation (λ ≥ 420 nm) due to the higher photocatalytic activities of NiSnxOy and the electron transfer function of graphene sheets. The highest apparent quantum efficiency (AQE) of 36.2% over EY-NiSnxOy/G was achieved at 430 nm.