Nitrogen Doping-Roused Synergistic Active Sites in Perovskite Enabling Highly Selective CO₂ Photoreduction into CH₄.

Abstract

The intricate protonation process in carbon dioxide reduction usually makes the product unpredictable. Thus, it is significant to control the reactive intermediates to manipulate the reaction steps. Here, we propose that the synergistic La-Ti active sites in the N-La₂Ti₂O₇ nanosheets enable the highly selective carbon dioxide photoreduction into methane. In the photoreduction of CO₂ over N-La₂Ti₂O₇ nanosheets, <i>in situ</i> Fourier transform infrared spectra are utilized to monitor the *CH₃O intermediate, pivotal for methane production, whereas such monitoring is not conducted for La₂Ti₂O₇ nanosheets. Also, theoretical calculations testify to the increased charge densities on the Ti and La atoms and the regulated formation energy barrier of *CO and *CH₃O intermediates by the constructed synergistic active sites. Accordingly, the methane formation rate of 7.97 μL h^-1 exhibited by the N-La₂Ti₂O₇ nanosheets, along with an electron selectivity of 96.6%, exceeds that of most previously reported catalysts under similar conditions.