Direct capture of low-concentration CO2 and selective hydrogenation to CH4 over Al2O3-supported Ni–La dual functional materials

• Published in: Green chemistry : an international journal and green chemistry resource : GC Vol. 26; no. 21; pp. 10842 - 10850
• Main Authors: Tatsumichi, Tomotaka, Okuno, Rei, Hashimoto, Hideki, Namiki, Norikazu, Maeno, Zen
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 28.10.2024
• Subjects: Air temperature; Aluminum oxide; Carbon dioxide; Carbon sequestration; Exhaust emissions; Exhaust gases; Functional materials; Hydrogenation; Methanation; Methane; Nanoparticles; Surface reactions; X-ray diffraction
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/d4gc03218g

CO2 capture and reduction with H2 (CCR) to synthesise CH4 over dual-functional materials (DFMs) possessing CO2 capture and hydrogenation abilities has recently attracted attention as a promising methodology for utilising low-concentration CO2 in air or exhaust gases without pressure and/or temperature swing operations. Much effort has been devoted to the development of Ni-based DFMs for the CCR of CH4 formation owing to their low cost and high catalytic potential for methanation. However, previous studies have been investigated under relatively high reaction temperatures (400–600 °C) and/or pressurised H2 conditions. In addition, experiments were conducted in the absence of O2 in the simulated CO2 gas. The development of efficient Ni-based DFMs under milder and more realistic reaction conditions is still necessary. In this study, we developed La-modified Al2O3-supported Ni nanoparticles (Ni–La(X)/Al2O3, X denotes the La loading) for the selective formation of CH4 from low-concentration CO2 (1%) in a simulated gas containing O2 (20%). The optimised Ni–La(15)/Al2O3 showed 99% selectivity for CH4 formation under isothermal (350 °C) and non-pressurised conditions. The effect of the La loading amount on the CCR performance was studied using X-ray diffraction, temperature-programmed surface reactions, and steady-state CO2 hydrogenation. Furthermore, the developed Ni–La(15)/Al2O3 was applied to direct capture of ultralow concentration CO2 in air (ambient direct air capture (DAC)) and methanation.