The Performance and Mechanism of the FeCe-Hβ Catalyst on the Regeneration of CO₂-Loaded PZ-<i>n</i>-Butanol-H₂O System

Amine-based carbon dioxide capture technologies are important for carbon emission reduction and carbon neutralization but are hindered by low absorption capacities and high regeneration energy requirements. This study introduces a series of Fe2O3-CeO2/Hβ (FeCe-Hβ) catalysts, synthesized via an ultrasound-assisted self-assembly method, to enhance CO2 desorption in the “PZ-n-butanol-H2O” phase change system. The FeCe-Hβ catalysts demonstrated superior catalytic performance characterized by increased CO2 desorption rates, enhanced desorption capacities, and reduced carbamate decomposition heat. Notably, the 30FeCe-Hβ catalyst improved CO2 desorption capacity by 37.29% and reduced the decomposition heat of PZ-carbamate by 13.91%. Compared to a 30 wt% monoethanolamine (MEA) aqueous solution, it achieved an 80.39% increase in CO2 desorption. Structural and physicochemical analyses revealed that the synergistic effects of acidic and basic sites, along with the mesopore surface area*Bro̷nsted acid sites (MSA*BAS) parameter, were pivotal to the catalyst’s performance. Stability tests indicated that 30FeCe-Hβ retained its activity, with only a 6.3% decrease in CO2 desorption after five cycles. Mechanistic investigations proposed that CO2 absorption products compete with n-butanol for water molecules, inducing a phase change. The FeCe-Hβ catalyst facilitated CO2 desorption through acid–base site synergy, where acidic sites promoted the cleavage of PZCOO–/PZ(COO–)2 and basic sites aided in PZH+/PZH22+ deprotonation.