Abstract: Presented herein are the delicate design and synthesis of S-scheme NiTiO₃/CdS heterostructures composed of CdS nanoparticles anchored on the surface of NiTiO₃ nanorods for photocatalytic CO₂ reduction. Systematic physicochemical studies demonstrate that NiTiO₃/CdS hybrid empowers superior light absorption and enhanced CO₂ capture and activation. Electron spin resonance validates that the charge carriers in NiTiO₃/CdS follow a S-scheme transfer pathway, which powerfully impedes their recombination and promotes their separation. Importantly, the photogenerated holes on CdS are effectively consumed at the hero-interface by the electron from NiTiO₃, preventing the photo-corrosion of the metal sulfide. As a result, with Co(bpy)₃²⁺ as a cocatalyst, NiTiO₃/CdS displays a considerable performance for CO₂ reduction, affording a high CO yield rate of 20.8 μmol h^-1. Moreover, the photocatalyst also manifests substantial stability and good reusability for repeated CO₂ reaction cycles in the created tandem photochemical system. In addition, the possible CO₂ photoreduction mechanism is constructed on the basis of the intermediates monitored by in-situ diffuse reflectance infrared Fourier transform spectroscopy.

Key words: Photocatalysis, S-scheme, CO₂ reduction, Heterojunction, NiTiO₃