Ru/ZrO2 as a Facile and Efficient Heterogeneous Catalyst for the Catalytic Hydrogenation of Bicarbonate Using Biodiesel-Waste Glycerol as a Hydrogen Donor

Direct hydrogenation of CO2 (or HCO3-) into chemicals using organic waste biomass as a hydrogen donor is a promising carbon-negative strategy to alleviate the global warming caused by excessive CO2 emission. However, the reported conversion efficiencies are quite limited. In this work, a facile Ru/ZrO2 catalyst was developed to catalyze the hydrogenation of HCO3- into formate by using biodiesel-waste glycerol as the reductant. It was found that ruthenium can significantly promote the dehydrogenation of glycerol to provide in situ hydrogen for HCO3- hydrogenation according to the in situ Fourier transform infrared spectrometer analysis. Moreover, hydrogen spillover between ruthenium and ZrO2 support was also formed. Consequently, efficient hydrogen transfer could be constructed in the presence of Ru/ZrO2, achieving desirable in situ hydrogenation of HCO3(-) into formate eventually. The highest yield of formate up to 25.1% was obtained over Ru/ZrO2, while the formate yield was only 4.2% in the case without catalysts.