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

Abstract

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.