Dual-Function Orchestration of N-Doped Cu Nanocatalysts for CO <sub>2</sub> Hydrogenation to Methanol
Jucang Ke, Xiuyun Jiang, Qingxiang Ma, Hao Song, Baojian Chen, Chufeng Liu, Xinhua Gao, Hanyao Song, Haozhe Feng, Jianli Zhang, Guangbo Liu, Tiansheng Zhao, Noritatsu Tsubaki
Abstract
Copper-based catalysts remain among the most extensively studied systems for the hydrogenation of CO 2 to methanol owing to their high catalytic performance. However, advancements in the development of copper-based catalysts rely heavily on the incorporation of metal additives and the utilization of catalyst supports. In this study, an unsupported, nonmetallic N-doped Cu nanocatalyst was prepared by an ammonia complexation precipitation method, which has favorable catalytic performance in the hydrogenation of CO 2 to methanol. The conversion of CO 2 and selectivity of methanol reach up to 6.9 and 71.7% (240 °C, 3.0 MPa), respectively. Based on combined structural and electronic property analyses with density functional theory calculations, N species doped at copper interstitial sites exhibit enhanced CO 2 adsorption capacity through interactions with copper and induce the in situ formation of additional Cu + species from Cu 0 under a CO 2 atmosphere, thereby constructing bifunctional Cu 0 /N-Cu + catalytic sites. Within these sites, Cu 0 sites promote hydrogen dissociation, while Cu + sites interacting with nitrogen synergistically facilitate the CO 2 adsorption and activation. This enables the stepwise hydrogenation of the CO 2 -derived intermediates into methanol.