Nanocrystalline High-Dimensional Nb<sub>2</sub>O<sub>5</sub> for Efficient Electroreductive Dicarboxylation of CO<sub>2</sub> with Cycloalkane
Yuanming Xie, Xinlin Wang, Junjun Mao, Chenchen Zhang, Qingqing Song, Toru Murayama, M. C. Lin, Jiawei Zhang, Yang Lou, Chengsi Pan, Ying Zhang, Yongfa Zhu
Abstract
The electrocarboxylation of C–C single bonds using CO 2 under ambient conditions is a promising strategy for synthesizing diacids, which have significant applications in polymer and biomedical sectors. In this study, we present the development of nanocrystalline Nb 2 O 5 featuring a high-dimensional structure (Nb 2 O 5 –HD) that enables the efficient dicarboxylation of CO 2 with cycloalkanes under mild conditions. Utilizing commercially available, unactivated diethyl cyclopropane-1,2-dicarboxylate as a model substrate, we achieved an impressive average yield of approximately 94%, with an 88% yield demonstrated in a gram-scale experiment. Notably, Nb 2 O 5 –HD maintained its structure and performance after 100 h of continuous operation, highlighting its long-term stability. In situ mechanistic investigations elucidated the reaction pathway, revealing that the CO 2 radical anion (CO 2 •– ) serves as an essential intermediate driving the reaction rather than cycloalkane adsorption onto the cathode. Besides, the high-dimensional structure and abundant crystal defects of Nb 2 O 5 –HD exhibit a greater number of acid sites, which is advantageous for the generation and stabilization of the CO 2 •– . These findings underscore the potential of Nb 2 O 5 –HD as a robust catalyst for CO 2 conversion, paving the way for advancements in organic electrosynthesis.