Significantly Enhanced Photoelectrocatalytic Alcohol Oxidation Performance of CdS Nanowire-Supported Pt via the "Bridge" Role of Nitrogen-Doped Graphene Quantum Dots

Environmentally friendly, high energy conversion efficiency, and low pollution emission direct alcohol fuel cells (DAFCs) represent an ideal future clean renewable energy source. Herein, N-doped graphene quantum dots (N-GQDs) are introduced into cadmium sulfide (CdS) nanowires to form a "dot-on-nanowire" structure and support Pt nanoparticles to fabricate the electrode material, which is the core component of fuel cells. With the assistance of visible light irradiation, the asprepared Pt-CdS/N-GQD electrode displays 2.7, 3.9, and 8.1 times improved electrocatalytic performance on methanol, ethanol, and ethylene glycol oxidation compared to the Pt-CdS one, respectively. Meanwhile, another essential parameter to evaluate the catalytic properties, the long-term stability of the corresponding electrode, is also significantly promoted under visible light illumination. The N-GQDs served as the "bridge" to link the photo- and electrocatalytic processes for facilitating efficacious interfacial charge transfer and the separation of photogenerated electron-hole pairs in the Pt-CdS/N-GQD electrode, which contributes to the synergistic effect of photoelectrocatalysis for the promotion of catalytic efficiency and stability. The present studies provide a promising avenue to design the high photoelectrocatalytic activity and superior poison resistance electrode materials for application in DAFCs.