Kinetics and mechanism of reduction of CO2 by glycerol under alkaline hydrothermal conditions

•A kinetic model comprising reduction of CO2 and glycerol conversion is elucidated.•The estimated apparent activation energy of the main reaction is 41 kcal/mol.•From the theoretical study, transition state structures have been determined.

The increasing greenhouse gas emission strongly requires new efficient methods to close the carbon cycle. One promising strategy is to achieve reduction of CO2 and utilization of glycerol simultaneously in one-pot hydrothermal reaction. A possible mechanism through hydrogen-transfer reduction from glycerol was proposed by previous researchers. However, the detailed mechanism is still not clear, which prohibits the development of catalyst. In this study, by adopting a joint experimental and theoretical method, a kinetic model comprising reduction of CO2 and glycerol conversion is elucidated. The activation energy values are obtained in experimental and theory, respectively. The reduced species was found to be CO2 not bicarbonate based on the theoretical calculation.

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