Photocatalytic CO₂ Transformation to CH₄ by Ag/Pd Bimetals Supported on N-Doped TiO₂ Nanosheet

Abstract

To develop photocatalysts with desirable compositions and structures for improving the efficiency and selectivity of CO₂ conversion to CH₄ under mild conditions is of great importance. Here, we design an effective photocatalyst of bimetal (Ag/Pd) nanoalloys supported on nitrogen-doped TiO₂ nanosheet for CO₂ conversion. Such a novel photocatalyst combines multiple advantages of abundant Ti³⁺ ions, oxygen vacancies, and substitutional nitrogen that are favorable for catalyzing CO₂ reduction. It was found that CO₂ could be efficiently transformed to CH₄ under mild conditions, i.e., in aqueous solution and at atmospheric pressure and room temperature. The maximum production rate of CH₄ can reach 79.0 μmol g^-1 h^-1. Moreover, the Ag/Pd bimetals supported on N-doped TiO₂ nanosheet exhibit high selectivity to CH₄. The as-synthesized photocatalyst can be well recycled for CO₂ reduction.