Kai Zheng, Bangwang Li, Yue Zheng, Xiulai Zhang, Runhua Chen, Shengyue Zhang, S. Liu, Juncheng Zhu, Jianyi Liu, Wenxiu Liu, J. Y. Hu, Chengyuan Liu, Fanfei Sun, Zhongqin Dai, Yongfu Sun, Yi Xie
ABSTRACT Photocatalytic CO 2 methanation is fundamentally constrained by two intertwined bottlenecks: inefficient proton generation from H 2 O dissociation and the premature desorption of the critical * CO intermediate. Here, we design metal cation vacancy clusters‐O − motifs for accelerating H 2 O dissociation and boosting * CO protonation, while supported metal sites for CO 2 activation over metal‐anchored metal oxide nanosheets. As a prototype, we fabricate Au/TiO 2 ‐ V Ti nanosheets, where synchrotron‐radiation X‐ray absorption fine structure and electron paramagnetic resonance spectroscopy confirm V Ti ‐O − and coordination‐unsaturated Au sites. Density‐functional‐theory calculations reveal the creation of V Ti ‐O − sites drive the step of * CO protonation toward * CHO from an endothermic process (0.09 eV) to an exothermic one (−0.29 eV), and concurrently the energy for H 2 O dissociation into protons is lowered by a factor of two (1.31 eV → 0.65 eV). In situ Fourier‐transform infrared spectroscopy directly captures a distinct * CO intermediate, confirming its stabilization on the photocatalyst surface and thereby promoting the protonation step toward * CHO. Consequently, the Au/TiO 2 ‐ V Ti nanosheets show a superior CH 4 formation rate of 156.5 µmol g −1 h −1 with near‐100% selectivity. Briefly, this work offers key insights into CO 2 methanation bottlenecks and proposes a catalyst design blueprint to advance CO 2 valorization.