Photocatalytic water splitting properties of Cu²⁺ exchanged Beta zeolites

Photocatalytic water splitting with solar energy is the most promising and environmentally friendly hydrogen production method. Having an efficient and cost-effective photocatalyst is key to hydrogen production. Cu dopant has been shown to greatly enhance photocatalytic activities. In this work, Cu²⁺ ions were doped into Beta zeolite powders (Cu-Beta) by the ion exchange method. The hydrogen evolution efficiency of Cu-Beta was much higher than the raw Beta zeolites without Cu loading. After solid phase reaction, the band gap of Cu-Beta reduced from 3.48 eV to less than 2 eV, and as a result enhanced the optical absorption intensity, particularly in the visible region. The best hydrogen evolution efficiency was 102.12 μmol · g^-1 · h^-1 when the treated temperature was 900 °C (Cu-Beta-900). The temperature of the solid phase reaction had an important influence on the photocatalytic performance of Cu-Beta; a suitable reaction temperature can greatly improve its photocatalytic performance.