Decoration of PdAg Dual-Metallic Alloy Nanoparticles on Z-Scheme α-Fe2O3/CdS for Manipulable Products via Photocatalytic Reduction of Carbon Dioxide

Metal nanoparticles have been extensively used as co-catalysts in photocatalytic systems in order to pursue improvements in both reaction kinetics and selectivity. In this work, PdAg dual-metallic nanoparticles synthesized by the co-reduction method were decorated on a well-established α-Fe 2 O 3 /CdS Z-scheme photoactive material as a co-catalyst to study their performance for promoting the photoreduction of CO 2 . Herein, α-Fe 2 O 3 and CdS were in situ synthesized on fluorine-doped tin oxide (FTO) glass by hydrothermal and SILAR (successive ionic layer adsorption and reaction) methods, respectively. The direct Z-scheme charge transfer path between Fe 2 O 3 and CdS and the effective electron migration toward the PdAg mainly contributed to the excellent photocatalytic CO 2 reduction performance. The controllable work function based on Pd (5.12) and Ag (4.26) constructed an appropriate band alignment with α-Fe 2 O 3 /CdS and displayed favorable production for CH 4 rather than CO. The optimum ratio of PdAg 1:2 performed a 48% enhancement than pure Pd for photoreduction of CO 2 . Meanwhile, the enhanced charge separation improved the photoelectrochemical performance and photocurrent generation, and reduced the electrical resistance between components. This work provided insights into the dual-metallic co-catalyst for boosting the activity and selectivity of photocatalytic CO 2 reduction.