Optimal Co doping to Ni-based catalyst to promote partial oxidation of methane for syngas production

Abstract

In this study, Co doped Ni-based catalyst were synthesized and employed for partial oxidation of methane for syngas production. Ni-Co bimetallic nanocatalyst displayed excellent catalytic performance at a temperature of 350 to 600 degrees C in fix-bed reactor. An optimal Co doping level (0.5 M Co precursor) with Ni, significantly favors low temperature (350 degrees C) partial oxidation of methane to H2 and CO, while higher Co doping (>= 0.7 M Co precursor) resulted in reduced catalytic activity, and reaction shifted toward complete oxidation to CO2. A 100-h long-term stability test of optimally Co-doped Ni-based catalyst (Ni1.2Mg0.5Al0.5Co0.5) at 400 degrees C demonstrated excellent catalytic activity, achieving 90% CH4 conversion, 78% H2 and 57% CO selectivities and an H2/CO ratio of 1.4 without any notable deactivation. Spent catalysts analysis revealed the formation of metallic Ni degrees and Co degrees particles with no evidence of coke deposition and negligible sintering during extended reaction periods. The strong catalytic performance is attributed to the formation of metallic Ni degrees and Co degrees particles, and Ni-Co alloy formation through synergistic interaction between Ni and Co that improves redox behavior and stability. The incorporation of Co into Ni-based catalysts induces structural distortions, leading to the formation of surfaceactive oxygen species (Ni-O/Co-O) and improved lattice oxygen mobility. The superior catalytic performance of Co doped Ni-based catalysts suggest that an optimal Co doping level improves the reaction efficiency by mitigating the coking and sintering issues.