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

Ubong J Etim,Yibing Song,Ziyi Zhong

doi:10.3389/fenrg.2020.545431

Abstract

Heterogeneous catalytic hydrogenation of carbon dioxide (CO2) to methanol is a practical approach to mitigating its greenhouse effect in the environment while generating good economic profits. Though applicable on the industrial scale through the syngas route, the catalyst of Cu/ZnO/Al2O3 suffers from a series of technical problems when converting CO2 to methanol directly, which include low single-pass conversion, low methanol selectivity, requiring high pressure and fast deactivation by the reverse water gas shift reaction. Over the years, intensive research efforts have been devoted to proffering solutions to these problems by modifying the existing catalyst or developing new active catalysts. However, the open question is if this type of widely used industrial catalyst still promising for CO2 methanolizing reaction or not? This paper reviews the history of the methanol production in industry, the impact of CO2 emission on the environment, and analyzes the possibility of the Cu/ZnO-based catalysts for the direct hydrogenation of CO2 to methanol. We not only address the theoretical and technical aspects but also provide insightful views on catalyst development.

Highlights

Carbon dioxide (CO2) is a greenhouse gas emitted into the atmosphere via the combustion of fossil fuels in vehicles and power plants, from many industrial processes, and household operations, etc. (Karl and Trenberth, 2003; Hansen et al, 2006; Lim, 2015)
The results found that 10 wt% CuZn/rGO catalyst exhibited a good activity for the CO2 hydrogenation, achieving 26 % CO2 conversion, methanol selectivity of 51%, and 424 ± 18 mgmethanol at 250°C under 15 bar after 5 h on a stream (Deerattrakul et al, 2016)
We have discussed the recent developments in the direct hydrogenation of carbon dioxide to methanol over the Cu/ ZnO-based catalysts

Summary

Introduction

Carbon dioxide (CO2) is a greenhouse gas emitted into the atmosphere via the combustion of fossil fuels (oil, coal, natural gas) in vehicles and power plants, from many industrial processes, and household operations, etc. (Karl and Trenberth, 2003; Hansen et al, 2006; Lim, 2015). The high-pressure approach using a conventional Cu/ZnO/Al2O3 methanol synthesis catalyst was applied to CO2 hydrogenation to methanol (Figure 2). For the industrial Cu/ZnO/Al2O3 catalyst, the Fourier-transform infrared spectroscopy analysis has shown that the hydrogenation of both formate and methoxy species is the rate-determining step in the methanol synthesis over Cu-based catalysts (Ojelade and Zaman, 2019).

Results

Conclusion