Upgrading biogas to metgas by bi-reforming over Y2O3 modified Ni/h-BN nanocatalysts

Abstract

The bi-reforming of biogas to high-quality metgas meet the requirement of green carbon science as well as methanol economy. Herein a series of rare earth oxides (Y₂O₃, La₂O₃, Sm₂O₃) modified Ni nano-catalysts supported on hexagonal boron nitride were prepared by ball-milling method. The optimized Ni-5Y₂O₃/h-BN displayed high catalytic activity and maintained catalytic stability within 100 h time-on-stream, and Ni-5Y₂O₃/h-BN-CO₂ after CO₂-pretreatment further maintained catalytic stability up to 120 h. The catalysts were comprehensively characterized by XRD, ICP-OES, N₂ physisorption, H₂-TPR, CO₂-TPD, SEM, HR-TEM, XPS, CH₄-TPSR/CO₂-TPSR, and so on, to elucidate the structure–property-performance relationship. The small-sized Ni nanoparticles (NPs) and high content of surface adsorbed oxygen species facilitate the adsorption and activation of reactant molecules, and enhanced the catalytic activity in terms of CH₄/CO₂ conversion. Furthermore, the strong interaction between small-sized Ni NPs and h-BN over Ni-5Y₂O₃/h-BN and Ni-5Y₂O₃/h-BN-CO₂, as well as the BO_x overlayer derived from the h-BN on Ni-5Y₂O₃/h-BN-CO₂, lead to the satisfying long-termed stability.