Improved photocatalytic hydrogen generation on Zn2GeO4 nanorods with high crystallinity

The rod-like Zn2GeO4 nanopowder was synthesized by a hydrothermal method and investigated for photocatalytic hydrogen generation from methanol aqueous solution. It is found that the post-calcination of Zn2GeO4 efficiently improves the photocatalytic activity while the morphology of Zn2GeO4 keeps almost unchangeable. The optimum photocatalyst Exhibits 430 μmol/h/g hydrogen evolution, which is more than 2 times higher than that of Zn2GeO4 without any calcination. XRD show the improvement of crystallinity of Zn2GeO4. UV–vis and photoluminescence spectra demonstrate the reduction of impurity in Zn2GeO4. It is supposed that the higher crystallinity and the reduction of impurity of Zn2GeO4 nanorod are mainly responsible to the improved activity. It is put forward that hydrothermal synthesis and then post-calcination is an efficient method to prepare highly active photocatalyst with high crystallinity and large surface areas.