Surface Lewis Acidity of Periphery Oxide Species as a General Kinetic Descriptor for CO2 Hydrogenation to Methanol on Supported Copper Nanoparticles

Jonglack Kim,Bidyut B Sarma,Gonzalo Prieto,Norbert Pfänder,Eva Andrés,Patricia Concepción

doi:10.1021/acscatal.9b02412

Abstract

Oxide-supported copper nanoparticles exhibit promising properties as catalysts for the selective hydrogenation of CO2 to methanol. Both reaction rate and selectivity depend conspicuously on the nat...

Highlights

The past decade has witnessed a surge in the development of catalysts and processes for the chemical recycling of CO2 into platform chemicals, which is regarded as a means to reduce net anthropogenic CO2 emissions and turn waste carbon dioxide into a valuable feedstock for the chemical industry
Our results contribute a unifying and quantitative description for support effects in CO2 hydrogenation to methanol on oxide-supported copper nanoparticles and provide a blueprint for a predictive description of metal-oxide promotion effects, which are ubiquitous in heterogeneous catalysis
Making use of a set of high-surface-area model catalysts where copper nanoparticles have been interfaced with a variety of transition metal oxides, the current study shows that a single experimentally quantifiable physicochemical parameter, that is, the Lewis acidity of coordinatively unsaturated metal centers exposed on the surfaces of those oxide species at the periphery of the metal nanoparticles, determines the overall energy barrier for the reaction in a broad study space

Summary

■ INTRODUCTION

The past decade has witnessed a surge in the development of catalysts and processes for the chemical recycling of CO2 into platform chemicals, which is regarded as a means to reduce net anthropogenic CO2 emissions and turn waste carbon dioxide into a valuable feedstock for the chemical industry. Research Article the SiO2 surface, that is, in close proximity to the copper nanocrystals, was shown to enhance methanol formation rates to variable extents, which depended markedly on the nature of the oxide promoter This remarkable variability of the catalytic performance as a function of the nature of the oxide at the periphery of the metal nanoparticles makes the Cu-catalyzed CO2 hydrogenation a paragon of the so-called metal-oxide promotion effects by which the direct contact of metal and oxide species modifies profoundly the catalytic performance of the individual components. In situ and temperature-resolved FTIR studies suggest that the destabilization of bidentate formate reaction intermediates on oxide surface centers of increasingly higher electron-accepting character provides an energetically more favorable reaction pathway toward methanol formation

■ RESULTS AND DISCUSSION

■ CONCLUSIONS

■ ACKNOWLEDGMENTS

■ REFERENCES