《Nano Lett.》: Nitrogen Doping-Roused Synergistic Active Sites in Perovskite Enabling Highly Selective CO₂ Photoreduction into CH₄

Qinyuan Hu,⁺ Mengqian Li,⁺ Juncheng Zhu,⁺ Zhixing Zhang, Dongpo He, Kai Zheng, Yang Wu, Minghui Fan, Shan Zhu, Wensheng Yan, Jun Hu, Junfa Zhu, Qingxia Chen,^* Xingchen Jiao,^* and Yi Xie^*

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 CO₂ photoreduction over N-La₂Ti₂O₇ nanosheets, in situ 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 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.

Figure 1. Regulating the reaction step in CO₂ reduction pathways. (a) the single active-site catalyst and (b) the synergistic active-site catalyst.