Since the advent of industrial revolution, the accumulation of carbon dioxide (CO 2 ) in the Earth's atmosphere has raised significant environmental and climate concerns. As a response to this pressing challenge, the conversion of CO 2 into chemicals and/or fuels through direct hydrogenation has emerged as a widely recognized and imperative strategy for mitigating both CO 2 emissions and fossil fuel consumption.
Among the array of catalysts investigated for CO 2 hydrogenation, copper (Cu)-based catalysts have garnered increasing attention for their promising potential in the production of methanol. However, despite the promising catalytic activity exhibited by Cu-based catalysts, their practical application in CO 2 hydrogenation faces a significant difficulty arising from the intrinsic reduction and aggregation tendencies of the Cu-based active centers, particularly at the elevated operating temperatures. This propensity for reduction and aggregation could potentially result in larger Cu particles, consequently diminishing the CO 2 hydrogenation activity and leading to the generation of undesired CO byproducts. As a result, this pose a considerable impediment to simultaneously achieving the desired high catalytic activity and methanol selectivity, which are benificial for large-scale industrial applications.
To address these challenges, the research team led by Professor Hai-Long Jiang from the University of Science and Technology of China (USTC) has proposed a novel strategy aimed at immobilizing and stabilizing single-atom Cu sites within a metal-organic framework-based catalyst by creating the Na + decorated microenvironment in close proximity. Through comprehensive experimental and theoretical calculation investigations, they have uncovered the importance of Na + -decorated microenvironment around the single-atom Cu sites. This microenvironment plays a crucial role in maintaining the atomic dispersion of Cu sites during the CO 2 hydrogenation process, even at high temperatures reaching up to 275 °C, through the electrostatic interaction between Na + and H δ- species. This exceptional stabilization effect of single-atom Cu sites has endowed the catalyst with excellent CO 2 hydrogenation activity (306 g·kg cat -1 ·h -1 ), high selectivity to methanol (93%), and long-term stability, far surpassing its counterpart lacking the presence of Na + . This groundbreaking work not only advances the development of Cu-based catalysts for selective CO 2 hydrogenation to methanol, but also introduces an effective strategy for fabricating stable single-atom sites in advanced catalysis by creating alkali-decorated microenvironments in close proximity.
National Science Review