Role of S, N co-doped graphene quantum dots as a green photosensitizer with Ag-doped ZnO nanorods for improved electrochemical solar energy conversion

Photoelectrochemical (PEC) properties of Ag doped ZnO nanorods (Ag-ZnO NRs) have been studied in details. Ag-ZnO NRs photoanodes demonstrated superior photoconversion efficiency (i.e. photon to hydrogen), photoresponse properties, incident-photon-to-current conversion efficiency (IPCE), compared to pristine ZnO nanorods. S and N co-doped graphene quantum dots (S,N-GQDs) were synthesized by hydrothermal process and utilized as a green photosensitizer for further improvement of photoelectrochemical activities. S,N-GQD sensitized nanorods showed photoconversion efficiency (eta) similar to 1.1%, and short circuit photocurrent (Jsc) similar to 0.96 mA/cm(2), which are 3.4 times and 2.7 times higher than ZnO NRs. Sensitization with S,N-GQDs also improved the IPCE value and attained maximum 62.8% at 350 nm, which is 2.2 times higher compared to ZnO NRs. (C) 2017 Elsevier Ltd. All rights reserved.