Investigation on Deactivation of Cu/ZnO/Al₂O₃ Catalyst for CO₂ Hydrogenation to Methanol

Abstract

The catalytic performance of Cu/ZnO/Al 2 O 3 (CuZnAl) catalyst for CO 2 hydrogenation to methanol was investigated over a period of 720 h time-on-stream, which showed that the space time yield of CH 3 OH was decreased by 34.5% during the long-term testing. Different characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), and N 2 O adsorption experiments, were applied to study the deactivation reasons. XRD and N 2 O adsorption experiments indicated that there were no obvious changes in Cu particle size after the CuZnAl catalyst was exposed to reaction atmosphere for 720 h, while agglomeration took place on ZnO particles. XPS results revealed that part of the metallic Cu was oxidized to Cu 2+ . The CuZnAl catalyst deactivation was proved to be due to the comprehensive effect of Cu oxidation and ZnO species agglomeration during CO 2 hydrogenation to methanol.

Comparative study on the effect of different copper loading on catalytic behaviors and activity of Cu/ZnO/Al2O3 catalysts toward CO and CO2 hydrogenation

“…In both cases of CO and CO 2 hydrogenation, CZA-H catalyst exhibited lower coke deposition than CZA-L. According to the TGA analysis and catalytic activity results, it was suggested that the CZA-L catalyst with high ZnO content can migrate and generate the graphitic coke to block the active sites (Liang et al, 2019;Laudenschleger et al, 2020;Okemoto et al, 2020). Furthermore, large amounts of carbon deposition over CZA catalysts were formed by the decomposition of CO and CO 2 molecules with the reduction of ZnO and CuO, and Cu oxidation (Chiang et al, 2018), which was related to low catalytic activity as shown in Figure 6.…”

Improving the Cu/ZnO-Based Catalysts for Carbon Dioxide Hydrogenation to Methanol, and the Use of Methanol As a Renewable Energy Storage Media

“…The water generated in the RWGS during CO 2 reduction to methanol deactivates the catalyst, causing speciation of Cu active phase and phase separation (Kung, 1992;Liang et al, 2019;Prasňikar et al, 2019). Sahibzada et al observed a lower rate of methanol production in the presence of water in the H 2 /CO 2 feed (Sahibzada et al, 1998).…”

Heterogeneous Catalytic Hydrogenation of Carbon Dioxide Into Hydrocarbons: Achievements and Prospects

“…When using a zeolite catalyst, C2+ hydrocarbons of a certain composition were obtained by hydrogenation of carbon dioxide with the use of zeolite and mixed zeolite-oxide systems as catalysts. The dependence of the activity of these catalysts in the hydrogenation of CO2 to methanol and hydrocarbons on the amount of acid sites was studied [94][95][96]. The C5-C11 gasoline fraction was obtained with high selectivity on the In2O3 / HZSM-5 catalyst.…”