Regulating Product Selectivity in Photothermal CO <sub>2</sub> Conversion through Ni Loading on Metallic MoO <sub>2</sub>
Tingyu Yang, Hanmei Yang, Bo Su, Xiahui Lin, Xue Lu, Mengdi Wang, Wandong Xing, Yongzhao Wang, Xing Huang, S. M. Wang
Abstract
Photothermal CO 2 methanation builds a sustainable and energy-efficient strategy to convert CO 2 into value-added fuels under mild conditions. Herein, we report a broadband-responsive Ni/MoO 2 catalyst with tunable Ni loading for selective CO 2 hydrogenation under light irradiation. By systematically varying the Ni content, product selectivity can be exactly controlled: 0.2%-Ni/MoO 2 yields the highest CO production rate (2.67 mmol g –1 h –1 ), while 16%-Ni/MoO 2 reaches a CH 4 production rate of 36.45 mmol g –1 h –1 with nearly 100% selectivity. Structural characterization and in situ spectroscopic analyses disclose that low Ni loading favors NiO formation that captures photogenerated holes to enhance H 2 dissociation and promotes CO evolution via weak *CO adsorption. In comparison, high Ni loading generates metal Ni 0 encapsulated by NiO, which concentrates the photogenerated electrons to activate CO 2 and stabilize *CO intermediates, thereby driving hydrogenation toward CH 4 with high efficiency. This work clarifies a clear structure–selectivity relationship and highlights active-site engineering as an effective approach to optimize efficiency and selectivity in photothermal CO 2 conversion.