Two‐Stage Catalytic Conversion of Carbon Dioxide Into Aromatics Via Methane

Abstract

Abstract In the refinery of the future, the input shifts from crude oil to biomass, plastic, and CO 2 . Therefore, we need to find alternative routes to produce chemical building blocks, such as aromatics, which are used in products like, for example, fuels. In this study, we investigated a two‐stage route to produce benzene from CO 2 . In two sequential reactions, CO 2 is first converted into methane over a Ni/TiO 2 catalyst, and methane is further reacted to yield benzene using a Mo/ZSM‐5 catalyst via the methane dehydroaromatization (MDA) reaction. Through a combination of thermodynamic calculations and experiments, we found the goldilocks conditions for performing this two‐stage process. The unreacted CO 2 and H 2 from the first reaction extended the benzene production in the second reaction. Using a reaction mixture of CO 2 , H 2 , and CH 4 resulted in benzene production of at least 72 h, by suppressing carbon growth on the catalyst surface. However, the concentration range in which CO 2 and H 2 can be added to the feed without losing benzene production is narrow, as we show with H 2 fluctuation experiments. We demonstrate that the combination of CO 2 methanation and MDA allows us to catalytically convert CO 2 into benzene with an overall yield of 5%.