Enhanced photocatalytic hydrogen production by CdS nanofibers modified with graphene oxide and nickel nanoparticles under visible light

Cadmium sulfide fibers were synthesized and modified with graphene oxide sheets (GO) and nickel nanoparticles to enhance the photocatalytic hydrogen production from ethanol-water solutions using visible light. To find an optimal content of GO, the concentrations of 1, 3 and 10 wt% were evaluated. Two different synthesis methods, photodeposition and in-situ, were used in order to determine the effect of the preparation on the resulting photoactivity. Finally, these composites were modified by the photodeposition of 0.5 wt% of Ni nanoparticles to enhance the hydrogen evolution. The photoactivity was evaluated using 4 LED lamps of lambda = 450 nm (4 W each) using ethanol solutions (50/50 vol%) as sacrifice molecule. The results show that the material modified with 10 wt% of GO prepared by the in situ method, increased the hydrogen production in a factor of 1.8 compared to the photoactivity reported for CdS. The most active material was obtained when Ni nanoparticles were supported on the Ni/GO-CdS 1% composite, increasing in a factor of 6.3 (8866 mu mol/h.g) the photoactivity reported for the bare semiconductor CdS (1410 mu mol/h.g).