Advancing efficient green CO2 capture with hydrothermally recyclable Zr(HPO4)2 catalysts: Experimental and DFT insights

Abstract

Catalytic amine–based solution regeneration has attracted considerable attention due to its potential to reduce energy consumption in carbon dioxide (CO₂) separation. However, the limited catalytic activity and cycling stability of catalysts under high–temperature alkaline conditions hinder their industrial application. Herein, zirconium hydrogenphosphate (ZrHP) catalysts, featuring abundant acidic sites, were first utilized for amine solution regeneration. By leveraging its proton donation and acceptance mechanism, efficient monoethanolamine solution regeneration was achieved. The ZrHP–4 catalyst demonstrated a 526% increase in the instantaneous CO₂ desorption rate compared to the non–catalytic test, reducing the relative heat duty by 48%. Moreover, ZrHP–4 exhibited remarkable stability over 10 cycles without requiring regeneration. Density functional theory calculations revealed that ZrHP promotes CO₂ desorption by elongating the C—N bond of carbamate and lowering the proton transfer energy barrier. Therefore, this study offers novel insights into the design and mechanistic understanding of efficient and stable catalysts for amine solution regeneration.