Investigation of Ba doping in A-site deficient perovskite Ni-exsolved catalysts for biogas dry reforming.

This work presents the development of an A-site deficient La 0.9−x Ba x Al 0.85 Ni 0.15 O 3 (x = 0, 0.02, 0.04, and 0.06) perovskite oxide catalyst for dry reforming of model biogas. The catalysts are prepared using a citrate sol-gel method and used for biogas dry reforming at 800 °C for feed ratios (CH 4 /CO 2) of 1.5 and 2.0. The fresh and spent catalysts are analyzed using XRD, FTIR, TPD, XPS, FESEM, TEM, TPR, TGA-DTA, and Raman analysis. The XRD analysis exhibits the host perovskite oxide structure and the exsolved Ni phase for all prepared catalysts. The partial doping of Ba improves the metal support interaction and oxygen vacancies that enhance catalytic activity and stability, as revealed by the TPR and XPS analysis. The stability experiment on La 0.9−x Ba x Al 0.85 Ni 0.15 O 3 , for x = 0 catalyst resulted in reduced activity due to the catalyst deactivation by sintering, as confirmed by XRD and FE-SEM. Among all the catalysts studied, La 0.84 Ba 0.06 Al 0.85 Ni 0.15 O 3 (LB6AN-15) exhibited the highest catalytic stability with CH 4 , and CO 2 conversions are 60% and 93%, respectively, for 40 h time-on-stream due to the strong metal support interactions, high oxygen vacancies, and anti-sintering of exsolved Ni nanoparticles in biogas dry reforming. [Display omitted] • Biogas dry reforming over Ni and Ba co-doped La 0.9 AlO 3 perovskite catalysts is carried out. • Fresh and spent catalysts retained their host perovskite structure. • An increase in the Ba loading enhances the metal support interaction. • The LB6AN-15 catalyst displayed high activity and stability in 40 h biogas dry reforming. [ABSTRACT FROM AUTHOR]