Enhanced simultaneous H 2 and CH 4 generation from formaldehyde using CdS/NiO x nanorods under visible light

Formaldehyde (HCHO) is a toxic by-product widely generated in industrial processes, presenting significant environmental and health risks. Utilizing solar energy to convert HCHO into hydrogen (H2) and other clean energy provides a sustainable solution for pollution control and energy demands. In this work, a highly active and low-cost CdS/NiOx photocatalyst was synthesized in situ and applied for the photocatalytic HCHO decomposition. For the first time, simultaneous generation of H2 and CH4 was observed during the photocatalytic decomposition of formaldehyde. The optimal H2 evolution rate can reach up to 13 mmol g−1 h−1, with a CH4 production rate of 175 μmol g−1 h−1 driven by visible light. The close contact between NiOx and CdS facilitates rapid charge transfer and separation, leading to exceptional photocatalytic performance. Additionally, an apparent quantum yield (AQY) of 2.4% for H2 production at 420 nm indicates the high solar energy conversion efficiency of the CdS/NiOx sample. This study presents a promising approach for the sustainable conversion of harmful formaldehyde into valuable energy resources.