The effect of silver nanoparticles/graphene-coupled TiO₂ beads photocatalyst on the photoconversion efficiency of photoelectrochemical hydrogen production

In this work, a novel configuration of the photoelectrochemical hydrogen production device is demonstrated. It is based on TiO₂ beads as the primary photoanode material with the addition of a heterostructure of silver nanoparticles/graphene. The heterostructure not only caters to a great improvement in light harvesting efficiency (LHE) but also enhances the charge collection efficiency. For LHE, the optimized cell based on TiO₂ beads/Ag/graphene shows a 47% gain as compared to the cell having a photoanode of commercial P25 TiO₂ powders. For the charge collection efficiency, there is a pronounced improvement of an impressive value of 856%. The reason for the improvement in light absorption is attributed to either the light scattering of TiO₂ beads or the surface plasmonic resonance on the Ag nanoparticles/graphene. The photoconversion efficiency (PCE) of the resulting cells is also presented and discussed. The PCE of the TiO₂ beads/Ag/graphene cell is approximately 2.5 times than that of pure P25 cell.