Enhanced Photocatalytic H_(2)-production Activity of CdS Nanoflower using Single Atom Pt and Graphene Quantum Dot as Dual Cocatalysts

摘要

Single-atom catalysts have high catalytic activity due to their unique quantum size effects and optimal atom utilization.Herein,visi-ble-light-responsive photocatalysts were designed by coupling CdS with graphene quantum dots(GQDs)and platinum single atoms(PtSAs).GQDs and PtSAs were successively loaded on ultrathin CdS nanosheets through freeze-drying and in-situ photocatalytic reduction.The synergistic effect between PtSAs and GQDs results in superior photocatalytic activity with a hydrogen production rate of 13488μmol h^(-1)g^(-1)as well as the maximum apparent quantum efficiency(AQE)of 35.5%in lactic acid aqueous solution,which is 62 times higher than that of pristine CdS(213μmol g^(-1)h^(-1)).The energy conversion efficiency is ca.13.05%.As a photosensitizer and an electron reservoir,GQDs can not only extend the light response of CdS to the visible-light region(400-800 nm),but also promotes the separation of photoinduced electron-hole pairs.Meanwhile,PtSAs,with unique electronic and geometric features,can provide more efficient proton reduction sites.This finding provides an effective strategy to remarkably improve the photocatalytic H_(2) production performance.