Ag loaded on layered perovskite H2SrTa2O7 to enhance the selectivity of photocatalytic CO2 reduction with H2O

Layered perovskite material H2SrTa2O7 (HST) with good charge separation were prepared by polymerizable complex (PC) and ion-exchange methods for photocatalytic CO2 reduction. To overcome the defect of low selectivity, Ag particles as cocatalyst were loaded on HST to construct the active sites for CO2 reduction. The characterization revealed that Ag metal (Ag-0) particles were located on the edge of HST selectively due to structural anisotropy of layered perovskite material, maintaining the good separation of reduction sites and oxidation sites in space. Ag particles can reduce the overpotential of CO evolution and spur more electrons from HST used to reduce CO2 to CO instead of reducing H+ to H-2, thus promoting the selectivity toward CO evolution. The 0.5 wt% Ag/HST photocatalyst exhibited the maximum selectivity of CO (60.9%), which is 2.1 times of that of pure HST (28.5%). This work provides guidance on preparing photocatalysts with high selectivity of carbon products from CO2 reduction. (C) 2019 Elsevier B.V. All rights reserved.