Tuning Ag-modified NaTaO3 to achieve high CO selectivity for the photocatalytic conversion of CO2 using H2O as the electron donor

Abstract

Ag-loaded NaTaO3 was used for the photocatalytic conversion of CO2 using H2O as the electron donor, and the effect of the nanoparticle size, Ag loading, and crystal structure on the photocatalytic activity and CO selectivity were investigated. The sizes of the Ag nanoparticles could be tuned by controlling the photodeposition time, and relatively larger Ag nanoparticles were found to show higher CO selectivity. During the photocatalytic reaction, the initially polycrystalline Ag nanoparticles became single crystalline owing to the dissolution and redeposition of Ag, and the change in morphology reduced the CO selectivity. To solve this problem, Ag-Cr dual cocatalysts having a core–shell structure were developed. Subsequently, the locations and sizes of the Ag nanoparticles on the surfaces of NaTaO3 were maintained during the reaction because of the protection by the chromium shell, thus providing stable and selective CO production via the photocatalytic conversion of CO2 by H2O.