Nb-Doping Induced Structure Modulation and Synergistic Active Sites in W<sub>18</sub>O<sub>49</sub> to Enhance Methane Photosynthesis
Shupeng Wei, Yi Li, Xu Mao, Weisheng Hu, Benxia Li
Abstract
Solar-powered conversion of CO 2 and H 2 O into renewable fuels represents a promising technology for achieving carbon neutrality, while still remains considerable challenges because it involves a complex multistep electron–proton transfer mechanism including both CO 2 reduction and H 2 O oxidation. The establishment of synergistic redox active sites, along with a comprehensive understanding of the photocatalytic mechanism, is highly imperative. Herein, we developed a Nb-doped W 18 O 49 photocatalyst which features synergistic Nb 5+ -W δ+ active sites and exhibits efficient light absorption across the entire solar spectrum. This photocatalyst demonstrated outstanding photocatalytic performance in CO 2 and H 2 O conversion under simulated sunlight, achieving a CH 4 evolution rate of 20.27 μmol·gcat –1 ·h –1 with a selectivity of 82.6%. The Nb dopant introduces efficient active sites that synergistically interact with W δ+ sites to enhance CO 2 reduction and facilitate H 2 O oxidation for proton provision, thereby accelerating the whole reaction process by balancing the two half-reactions in kinetics. Moreover, the plasmon-induced infrared absorption results in a significant temperature increase, further accelerating the photocatalytic reaction. Key intermediates involved in the formation of CH 4 are monitored using in situ infrared spectroscopy, providing evidence for the understanding of CO 2 photoreduction mechanism. This study offers a novel perspective on designing efficient catalysts for artificial photosynthesis by constructing synergistic active sites to simultaneously promote CO 2 and H 2 O conversion.