CeMgOx-promoted Ni/boron nitride ultra-long stability bi-reforming for methanol-friendly syngas (H2/CO≈2): CO2/H2O activation and coke elimination mechanism

The use of biogas as renewable raw material to produce syngas（H 2 /CO ≈ 2）suitable for direct synthesis of methanol has attracted wide attention, but designing promising catalysts with high activity and stability remains a challenge. The catalytic systems used for this process usually have the characteristics of poor stability and easy carbon deposition. Here, Based on the Ce redox cycle and the strong metal-support interaction (SMSI), we designed and synthesized a series of Ni catalysts (denoted as Ni/CeMgO x /BN) with BN interfacial constraints. The abundant oxygen vacancy of reaction-induced Ce redox cycle endows Ni/CeMgO x /BN with excellent carbon resistance, because the ability to activate CO 2 /H 2 O is significantly enhanced. The CO 2 /H 2 O activation and carbon elimination mechanism were comprehensively characterized by in situ H 2 -TPR/CO 2 /H 2 O-TPSR, in situ CH 4 -TPSR/CO 2 /H 2 O-TPO, and FTIR, etc. Ascribed to the appropriate basicity of CeMgO x , homogeneous Ni dispersion, and strong interaction between Ni ultra-small nano particles (NPs) and CeMgO x /BN, Ni/CeMgO x /BN exhibit higher CO 2 /H 2 O adsorption/activation, higher CH 4 activation/dissociation, compared with another samples, which facilitate the formation of active oxygen species and intermediate coke removal, thus enhance the resistance to coke deposition and sintering. At 750 °C, Ni/CeMgO x /BN exhibit satisfying catalytic activity (CH 4 /CO 2 conversation 92 %/52 %) and superior stability (100 h) with negligible deactivation rates.