Synergistic enhancement of photocatalytic CO2 reduction by plasmonic Au nanoparticles on TiO2 decorated N-graphene heterostructure catalyst for high selectivity methane production

Energy-efficient photocatalytic CO2 reduction (PCO2R) into sustainable solar fuels is a highly enticing challenge for simultaneous settling of energy and environmental issues. Herein, we illustrate the synthesis and photocatalytic performance of a judiciously designed plasmonic Au nanoparticles photodeposited on TiO2-decorated N-doped graphene (ANGT-x) heterostructure catalyst showing remarkably enhanced CO2 reduction activity with high selectivity for methane production. Compared to typical binary Au-TiO2 photocatalyst, the ANGT2 exhibited almost 60 times higher electron consumption rate (Relectron) value ~ 742.39 µmol g−1h−1 for the reduced products, which, to the best of our knowledge is the highest PCO2R rate ever reported under comparable conditions. The superior performance of ANGT2 catalyst is attributed to the synergistic contributions from improved light absorbance, enhanced CO2 uptake together with improved charge transfer kinetics and efficient suppression of photogenerated (e-h) recombination rate bestowed by seamless interfacial contact between Au NPs and N-graphene-TiO2 components.