Bifunctional Acid Synergy in a Solid NiCo@C Catalyst for Promoted Amine Regeneration in CO ₂ Capture

The industrial application of MEA-based carbon capture processes is significantly constrained by a low desorption rate and high energy consumption. To address these limitations, a NiCo@C catalyst was synthesized by using a hydrothermal-assisted impregnation method. The incorporation of Ni–Co dual doping into the carbon-based framework not only enhanced its stability and catalytic activity but also optimized its pore structure. A series of systematic characterizations were performed to evaluate the physicochemical properties of the material. The results indicate that the NiCo@C catalyst exhibits a substantially larger specific surface area and pore size compared to the Ni@C and Co@C catalysts. Additionally, the bimetallic catalysts introduce both weakly acidic and strongly acidic sites while maintaining a well-defined three-dimensional spherical structure. Compared to the noncatalytic MEA system, the introduction of NiCo@C increases the maximum desorption rate by 158% and the maximum desorption amount by 41.24%. These improvements contribute to a 53.48% reduction in energy consumption along with excellent cycle stability. The catalytic mechanism of NiCo@C was further investigated using 13C NMR, FT-IR, and Raman spectroscopy. The results reveal that bifunctional acid synergy in the solid NiCo@C catalyst promotes proton transfer and facilitates the breaking of C–N bonds, thereby enabling more efficient desorption with a lower energy consumption.