The Effect of Alkali Metals (Li, Na, and K) on Ni/CaO Dual-Functional Materials for Integrated CO2 Capture and Hydrogenation

Ni/CaO, a low-cost dual-functional material (DFM), has been widely studied for integrated CO2 capture and hydrogenation. The core of this dual-functional material should possess both good CO2 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 CO2 capture-conversion activity over 20 cycles, with a high CO2 capture capacity of 10.8 mmol/g and a high CO2 conversion rate of 60.5% at the same temperature of 650 & DEG;C. The enhanced CO2 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 CO2 capture and release process and promoted DFM stability by hindering their aggregation and the sintering of DFMs.

Automated summary

It was found that the alkali metal-modified Ni/CaO dual-functional material (Na-Ni/CaO) exhibited stable CO2 capture-conversion activity over 20 cycles, with a high CO2 capture capacity of 10.8 mmol/g and a high CO2 conversion rate of 60.5% at 650°C. The improved CO2 capture capacity was attributed to the enhanced surface basicity of Na-Ni/CaO, and the incorporation of Na also contributed to the formation of double salts, which promoted the stability of the material.