Metal impregnated activated carbon as cost-effective and scalable catalysts for amine-based CO2 capture

Abstract

One of the main challenges of absorption-based CO2 capture hampering its industrial application is the huge energy penalty during solvent regeneration. The addition of a solid acidic catalyst to the solvent regeneration step can optimize the CO2 desorption at low temperatures and hence reduce the significant regeneration penalty. However, as the majority of the studied catalysts are costly, e.g., metal oxides and zeolites, and their addition can negate the benefit of lowered heat duty, the development of cost-effective and abundant materials is paramount. In this regard, we synthesized metal (Fe, Ni, Mo) supported activated carbon (AC) catalysts and evaluated their performance in the regeneration of the benchmark 5 M monoethanolamine (MEA) solution at 86 °C. The gathered data show that adding metal-impregnated AC catalysts can greatly improve amine solvent regeneration by boosting the rate of CO2 desorption by 113% and lowering the heat duty by 21.2% when compared to the noncatalytic MEA solution. Catalyst characterization data revealed that the CO2 desorption optimization is primarily governed by the number of acid sites available on the catalyst surface. The experimental results indicate that using scalable and inexpensive materials can significantly reduce the utility requirements for CO2 capture, ultimately advancing catalytic CO2 capture towards industrial implementation.