Facilitating proton-coupled electron transfer for energy-efficient CO2 desorption by C@ZrO2 hollow composites

Abstract

Catalyst-aided CO2 desorption offers a promising reduction in the energy penalty of amine scrubbing, but faces the challenges of slow mass transfer, sluggish desorption kinetics, and susceptibility to deactivation. In this work, a hollow composite catalyst C@ZrO2 was developed to simultaneously realize rapid electron, proton and mass transfer for CO2 desorption via facilitating proton-coupled electron transfer (PCET) effect. The CO2 desorption rate of benchmark MEA solution increased by 126% and relative heat duty decreased by 69.9% in presence of C@ZrO2, and its catalytic performance didn’t noticeably decline after 10 cycles. Additionally, the desorption rate of biphasic solvents with a high viscosity increased by 112% and relative heat duty decreased by 57.3% with C@ZrO2. Based on theoretical calculation, the facilitated PCET efficiency of carbon layer increased the binding energy of carbamate to enhance its mass transfer rate from the liquid phase to the C@ZrO2 surface, and stretched the C-N bond to reduce the proton transfer energy barrier by 66.8%. This work provided a novel insight to design catalysts for energy-efficient and stable CO2 capture.