Carbon-resistant bifunctional catalyst composed of LaFeO3 enhanced Ni-CaO for integrated CO2 capture and conversion
Hengyu Wei, Min Lin, Juping Zhang, Di Gao, Yuhao Chen, Liang Zhang, Xing Zhu
Abstract
• LaFeO 3 acts as a structural stabilizer and active promoter for bifunctional materials. • LaFeO 3 introduction increases oxygen vacancies in the material. • LaFeO 3 lattice oxygen migration enhances material resistance to carbon deposition. Coupled calcium cycling and dry reforming of methane (CaL-DRM) process has garnered significant attention in recent years as a promising technique for the CO 2 capture and in-situ conversion. However, traditional Ni-CaO catalysts with substantial CaL-DRM activity are susceptible to severe carbon deposition, which greatly hinders their industrial application. A combination of sol-gel and impregnation methods to include LaFeO 3 into Ni-CaO to enhance CO 2 capture and conversion is utilized. The characterization results indicate that the incorporation of LaFeO 3 significantly improves the dispersion of Ni and CaO, increases the concentration of oxygen vacancies, effectively suppresses the sintering and carbon deposition, and improves the cycling stability of Ni-CaO. In addition, LaFeO 3 promotes the outward diffusion of lattice oxygen, thereby facilitating CO 2 capture and CH 4 conversion to syngas. At 700 ℃, up to 86.5 % CO 2 conversion, 87.6 % CO selectivity, and syngas yield close to the theoretical value of 1.0 were achieved over 5Ni-30CaO-LFO (30 wt% CaO). More importantly, the activity of catalyst remains almost unchanged after 30 cycles. This study introduces an innovative approach for CaL-DRM, showing significant potential for effective and stable CO 2 capture and in-situ conversion.