Manufacturers generally produce methanol, a key chemical building block and fuel, from petroleum-derived syngas, a mixture of carbon monoxide and hydrogen. Direct hydrogenation of the greenhouse gas carbon dioxide would be a more efficient and environmentally sustainable route to methanol. But practical catalysts capable of making this reaction happen on an industrial scale have been unavailable.
Scientists had shown earlier that indium oxide catalyzes the direct hydrogenation of CO2 to CH3OH on a lab scale. Javier Pérez-Ramírez of ETH Zurich and coworkers now demonstrate that zirconium oxide-supported In2O3 catalyzes the process under conditions similar to those required for industrial production (Angew. Chem. Int. Ed. 2016, DOI: 10.1002/anie.201600943).
The supported catalyst can convert CO2 and H2 to CH3OH over at least 1,000 hours of continuous use and outperforms most other hydrogenation catalysts. The researchers proved experimentally that oxygen vacancies on the catalyst surface make the reaction possible—a mechanism predicted by theoretical calculations from a team led by Qingfeng Ge of Southern Illinois University and Tianjin University (ACS Catal. 2013, DOI: 10.1021/cs400132a).
The ETH Zurich group optimized the reaction by adding CO to the starting materials and varying the temperature, both of which tuned the number of vacancies. The technique is “a long-sought breakthrough with the potential to realize continuous CO2 conversion to methanol on a commercial scale,” Ge says.
Pérez-Ramírez and coworkers have filed patent applications on the technology in collaboration with French energy firm Total, which has started pilot studies of the process.
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