The Effect of Alkali Metals on Ni/CaO Dual-Functional Materials for Integrated CO[sub.2] Capture and Hydrogenation

• Published in: Materials Vol. 16; no. 15
• Main Authors: Hu, Yong, Xu, Qian, Sheng, Yao, Wang, Xueguang, Cheng, Hongwei, Zou, Xingli, Lu, Xionggang
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.08.2023
• Subjects: Hydrogenation; China
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma16155430

Ni/CaO, a low-cost dual-functional material (DFM), has been widely studied for integrated CO[sub.2] capture and hydrogenation. The core of this dual-functional material should possess both good CO[sub.2] capture–conversion performance and structural stability. Here, we synthesized Ni/CaO DFMs modified with alkali metals (Na, K, and Li) through a combination of precipitation and combustion methods. It was found that Na-modified Ni/CaO (Na-Ni/CaO) DFM offered stable CO[sub.2] capture–conversion activity over 20 cycles, with a high CO[sub.2] capture capacity of 10.8 mmol/g and a high CO[sub.2] conversion rate of 60.5% at the same temperature of 650 °C. The enhanced CO[sub.2] capture capacity was attributed to the improved surface basicity of Na-Ni/CaO. In addition, the incorporation of Na into DFMs had a favorable effect on the formation of double salts, which shorten the CO[sub.2] capture and release process and promoted DFM stability by hindering their aggregation and the sintering of DFMs.