Efficient photocatalytic water-splitting performance by ternary CdS/Pt-N-TiO2 and CdS/Pt-N,F-TiO2: Interplay between CdS photo corrosion and TiO2-dopping

( )22Z-Scheme CdS/Pt-N-TiO2 and CdS/Pt-N,FTiO2 nanocatalysts were synthesized using a sol - gel impregnation method and evaluated for their photocatalytic H-2/O-2 production via overall water splitting, with no extrernal electron or hole acceptors. The 0.5CdS/Pt-N-TiO2 material achieved a photocatlytic production of 639 mu mol/g/h of H-2 in tandem with 319 mu mol/g/h of O-2. The photocatalytic H-2/O-2 production data show that N-incorporation in the TiO2 lattice boosts overall water splitting, while F-incorporation inhibits the catalytic performance. Quantitative monitoring of the photogenerated Ti3+-surface and TO3+-lattice electrons, as well as of the photogenerated holes (h(+)) by Electron Parmagnetic Resonce spectrsocopy, show that CdS/Pt-N-TiO2 achieves en- hanced e(-)/h(+) photogeneration due to intraband states generated by N-dopping, facilitating the flow of elec- trons via Pt to the valence band of CdS. The leaching of Cd2+ ions' due to phootocorrosion of the CdS quantum dots, was montiored in-situ using Anodic StrippingVoltammtery (ASV). The Cd2+ leaching data reveal a severe inhibition of CdS photocorrosion ofN-dopped catalysts, CdS/Pt-N-TiO2. This reveals a dual beneficial role of Natoms: [i] boosting the visible light photocactivity, and [ii] inhibiting CdS photocorrosoion. A consistent Zscheme reaction mechanism is proposed for the catalytic H-2,O-2 production by CdS/Pt-N-TiO2 and CdS/Pt-N-FTiO2 heterojunctions, taking into account the photoinduced e(-)/h(+) dynamics as well as the interfacial {CdS}/{Pt-N/F-TiO2} chemistry.