Selective CO<sub>2</sub> Photoreduction to CH<sub>4</sub> via Pd<sup><i>δ</i>+</sup>‐Assisted Hydrodeoxygenation over CeO<sub>2</sub> Nanosheets
Zhiqiang Wang, Juncheng Zhu, Xiaolong Zu, Yang Wu, Shu Shang, Peiquan Ling, Panzhe Qiao, Chengyuan Liu, Jun Hu, Yang Pan, Junfa Zhu, Yongfu Sun, Yi Xie
Abstract
Abstract Here, noble‐metal‐doped two‐dimensional metal oxide nanosheets are designed to realize selective CO 2 photoreduction to CH 4 . As a prototype, Pd‐doped CeO 2 nanosheets are fabricated, where the active sites of Pd δ + (2< δ <4) and Ce 3+ −O v are revealed by quasi in situ X‐ray photoelectron spectra and in situ electron paramagnetic resonance spectra. Moreover, in situ Fourier‐transform infrared spectra of D 2 O photodissociation and desorption verify the existence of the Pd−OD bond, implying that Pd δ + sites can participate in water oxidation to deliver H* species for facilitating the protonation of the intermediates. Furthermore, theoretical calculations suggest the Pd doping could regulate the formation energy barrier of the key intermediates CO* and CH 3 O*, thus making CO 2 reduction to CH 4 become the favorable process. Accordingly, Pd‐doped CeO 2 nanosheets achieve nearly 100 % CH 4 selectivity of CO 2 photoreduction, with the raising CH 4 evolution rate of 41.6 μmol g −1 h −1 .