Design of Au nanorods-based plasmonic catalyst in combination with nanohybrid Pd-rGO layer for boosting CO2 hydrogenation to formic acid under visible light irradiation

Abstract

In recent years, research on the use of surface plasmon resonance phenomena induced by visible to near-infrared light for photocatalytic reactions has attracted much attention from the viewpoint of solar energy utilization. It has been extensively researched that the plasmon-mediated catalytic reaction can be promoted due to the injection of energetic hot electrons originating during the relaxation process of the surface plasmon resonance (SPR) into the reaction substrate molecules. In this report, we have prepared Pd/Au NRs@rGO nanocatalyst in which Au nanorods (NRs) with plasmonic properties are surrounded by a layer of reduced graphene oxide (rGO) with excellent electrical conductivity, and Pd nanoparticles (NPs) are supported on the Au NRs to efficiently transport hot electrons to the reaction substrate. The successful synthesis of the catalyst was characterized by HAADF-STEM, TEM, UV–vis, XRD, XAFS, and ICP analysis. The applicability of the prepared catalyst was tested in the photocatalytic reduction of CO2 to formic acid (FA) reaction under visible light irradiation. A photocatalytic FA yield of 1.7 μmol was obtained in 24 h, which was 2.7-fold higher than in dark reaction conditions. The SPR enhancement of Pd/Au NRs in combination with rGO in Pd/Au NRs@rGO catalyst led to the superior product yield of FA under visible light irradiation and room temperature conditions.