Overcoming photocorrosion in CdS photocatalysts: the role of lignin-derived carbon Co-based composites in hydrogen production

Abstract The implementation of lignin composites with inexpensive metals for photocatalytic hydrogen production offers an economically viable solution to the global energy crisis. CdS, as a widely used photocatalyst, faces significant challenges such as rapid electron–hole recombination, severe photo-corrosion, poor stability, and easy aggregation of nanoparticles. To overcome these limitations, we synthesized a CdS@Co–N/C composite photocatalyst by in-situ loading CdS particles onto Co–N/C lignin carbon through a straightforward hydrothermal method. The uniform anchoring of CdS nanoparticles on Co–N/C prevents aggregation, mitigates photo-corrosion, increases the surface area to mass ratio, and generates an increased amount of active sites. With 100 mg of CdS@Co–N/C as the catalyst, the optimal photocatalytic hydrogen rate of generation reached 6.11 mmol g −1 , which was 8.40-fold greater than that of pure CdS. This lignin carbon composite demonstrated remarkable stability, maintaining high hydrogen production efficiency without significant decline after five cycles. Electrochemical experiments and DFT (Density Functional Theory) results suggested that the carbon sourced from lignin in the composite possesses conductivity and, in synergy with Co nanoparticles, serves as an electron acceptor, enhancing electron transfer and hastening the separation of photogenerated charge carriers in CdS, and thereby enhancing photocatalytic hydrogen production efficiency. This study proposes a simple, cost-effective and noble-metal-free method for hydrogen production.