We report the synthesis of highly active NiS/CdS photocatalysts via a simple hydrothermal loading method for H₂ evolution from lactic acid sacrificial solution under visible light. In the absence of noble metals, a high quantum efficiency of 51.3% was measured at 420 nm.

To construct photocatalytically active MOFs, various strategies have recently been developed. We have synthesized and characterized a new metal–organic framework (MOF-253-Pt) material through immobilizing a platinum complex in 2,2′-bipyridine-based microporous MOF (MOF-253) using a post-synthesis modification strategy. The functionalized MOF-253-Pt serves both as a photosensitizer and a photocatalyst for hydrogen evolution under visible-light irradiation. The photocatalytic activity of MOF-253-Pt is approximately five times higher than that of the corresponding complex. The presence of the short Pt⋯Pt interactions in the framework was revealed with extended X-ray absorption fine structure (EXAFS) spectroscopy and low temperature luminescence. These interactions play an important role in improving the photocatalytic activity of the resulting MOF.

Carbon nitride (CN) nanosheets with a thickness of around 3 nm were prepared by pyrolysis of urea. Well-dispersed Pt nanoparticles of about 3 nm were pre-loaded on CN nanosheets as the co-catalyst by chemical reduction in ethylene glycol. The Pt/CN sample showed a H₂ evolution rate of 45.1 μmol h⁻¹ from an aqueous solution of triethanolamine (TEOA) under visible light irradiation (λ > 420 nm). By simply adding a low-cost dye Erythrosin B (ErB) in the photoreaction suspension, a remarkably enhanced H₂ evolution rate of 652.5 μmol h⁻¹ was observed. Efficient electron transfer from excited ErB to the conduction band of CN is expected due to the energy difference between the LUMO level of excited ErB (−3.59 eV vs. vacuum level) and the conduction band potential of CN (−3.71 eV vs. vacuum level). A dye sensitization mechanism between ErB and CN is proposed. Upon irradiation with light of long wavelength (λ > 550 nm), the Pt/CN–ErB photocatalyst system still exhibited a high H₂ evolution rate of 162.5 μmol h⁻¹. The highest quantum efficiency of 33.4% was obtained at 460 nm. Moreover, the Pt/CN photocatalyst could be easily recycled by simple filtration and 90% of the activity was still kept after five consecutive runs.