Modulating acidity in nickel-modified H-β zeolite catalyzes low-energy regeneration of CO2‑captured amine solution

The regeneration of catalytic amine-based solvents using solid acid offers a promising approach to reduce energy consumption in CO 2 capture processes. Nickel-based solid acid catalysts, endowed with multiple Lewis acid sites, could enhance the efficiency of regeneration reactions. Nevertheless, the irregular pore structure of NiO and the deficiency in Brønsted acid sites posed significant challenges to the practical use of amine solvent regeneration in CO 2 vapor stripping processes. A highly effective solid acid catalyst, nickel-modified H-β (Ni/β), were synthesized to enhance CO 2 desorption from MEA solutions saturated with CO 2 . The catalyst with 1.25% Ni (1.25% Ni/β) exhibited the highest activity and stability, with a 43.19% increase in the amount of desorbed CO 2 and a 30.16% reduction in relative heat duty. The catalyst maintained excellent stability, enhancing the desorption performance of MEA after ten cyclic absorption–desorption experiments. According to theoretic calculations and experimental analyses, the incorporation of H-β zeolite significantly enhanced the specific surface area of the composite and introduced a substantial number of Brønsted acid sites. Concurrently, the introduction of metal nickel substituted the hydrogen proton on the hydroxyl groups of the H-β molecular sieve, increasing the Lewis acid sites and modulating the Brønsted-to-Lewis acid site ratio. The Brønsted acid sites functioned as proton donors, while the Lewis acid sites facilitated N-C bond cleavage, promoting carbamate decomposition and the deprotonation of protonated amines. This work presents a valuable solid acid catalyst for amine-based CO 2 capture and offers insights for developing innovative solid acids for various catalytic processes.