The construction of hybrid catalysts composed of inorganic semiconductors and molecular catalysts shows great potential for achieving high photocatalytic carbon dioxide (CO2) conversion efficiency. In this study, ZnIn2S4 was first synthesized via a solvothermal route. Gold (Au) and silver (Ag) nanoparticles were then deposited on ZnIn2S4 via the reduction of noble metal precursor by sulfur vacancy defects. The obtained composite was further combined with tetra(4-carboxyphenyl)porphyrin iron(III) chloride (FeTCPP) molecular catalyst for efficient photocatalytic CO2 conversion. The roles of different noble metal nanoparticles in charge separation and interfacial electron transfer have been comprehensively studied. The photocatalytic performance and photoelectrochemical characterizations demonstrate that the introduction of Ag or Au nanoparticles is beneficial for charge separation. More importantly, the presence of Ag nanoparticles plays a crucial role in promoting the interfacial charge transfer between ZnIn2S4 and FeTCPP, whereas, Au nanoparticles function as active sites for the water reduction reaction.