Porous hollow Ni/CaO dual functional materials for integrated CO2 capture and methanation

Abstract

Excessive CO2 emissions present significant environmental and energy challenges, driving the need for effective strategies to reduce CO2. Integrated CO2 capture and utilization (ICCU) processes have drawn considerable attention by combing carbon capture and catalytic conversion in a unified process. The rational design of efficient dual-functional materials (DFMs) is key to achieving high-efficiency ICCU processes. Here, we synthesized a series of CaO-based DFMs with varying Ni loadings, in which the porous hollow CaO prepared by a sacrificial template method was employed as the adsorbent. The porous hollow structure are effectively to improve the diffusion of CO2 species and provide sufficient space for volume expansion after CO2 capture. The optimized conditions for adsorption and catalytic sites were determined to be at 550 °C with 5wt% Ni loading. Under these conditions, the adsorption capacity of 5 %Ni/CaO-P reached 7.02 mmol·g−1 DFM, with a CH4 yield of 2.85 mmol·g−1 DFM and a CH4 selectivity of 94.09 %. After 19 cycles, the adsorption capacity of 5 %Ni/CaO-P is maintained at 4.50 mmol·g−1 DFM with a CH4 yield remaining stable at 0.50 mmol·g−1 DFM due to the slight sintering of Ni species. Integrated CO2 capture and methanation offer a pathway for carbon recycling, emissions reduction, and sustainable development.

Keywords

• Integrated CO2 capture and utilization
• Dual functional materials
• Carbon capture
• Methanation