Efficient nickel-based catalysts for amine regeneration of CO2 capture: From experimental to calculations verifications

High heat duty is an urgent challenge for industrial applications of amine-based CO 2 capture. The temperature (>110°C) of carbamate breakdown in amine regeneration requires large energy consumption. In this work, we report a novel, stable, efficient, and inexpensive Ni-HZSM-5 catalyst to improve the CO 2 desorption rate and reduce the heat duty. The impregnation method was applied for varying nickel content in the catalysts from 2.16 to 9.80 wt% in HZSM-5. The catalysts were characterized by scanning electron microscope, X-ray powder diffraction, N 2 adsorption–desorption, inductively coupled plasma-optical emission spectrometry, ultraviolet-visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, NH 3 -temperature programmed desorption (TPD), Infrared spectroscopy of pyridine adsorption, and Fourier transform infrared spectroscopy. The catalytic performance was evaluated by CO 2 desorption of rich amine solvent at 90°C. It was found that the introduction of nickel increased the acid sites of catalysts compared with parent HZSM-5. This phenomenon plays a key role on improving the CO 2 desorption rate. The density functional theory (DFT) calculations successfully explain the catalytic performance. The catalytic activity associates with the combined properties of MSA × B/L × Ni 2+ . The 7.85-Ni-HZ catalyst presents an excellent catalytic activity for the CO 2 desorption: it increases the amount of desorbed CO 2 up to 36%, reduces the relative heat duty by 27.07% with the same reaction time, and possesses high stability during five cyclic tests. A possible catalytic mechanism for the Ni-HZSM-5 catalysts through assisting carbamate breakdown and promoting CO 2 desorption is proposed based on experimental results and theoretical calculations. Therefore, the results present that the 7.85-Ni-HZ catalyst significantly accelerates the protons transfer in CO 2 desorption and can potentially apply in industrial CO 2 capture.