Co-Ni bimetallic supported on mullite as a promising catalyst for biogas dry reforming toward hydrogen production

Abstract

Dry reforming of methane, in which harmful greenhouse gases convert to syngas, is one of the most important approaches to reducing concerns about global warming and increasing greenhouse gases. It was well found that support has a key role in the catalytic performance of heterogeneous catalysts in all aspects of chemistry. In this study, the effect of mullite(3Al2O3·2SiO2) ceramics as a support for the immobilization of Ni and Co to prepare bimetallic catalyst was explored in dry reforming of methane (DRM) at a temperature range of 650–800°C and gas hour space velocity (GHSV) equal to 15000 ml g⁻¹ h⁻¹. To evaluate the synergetic effect of the Ni-Co alloy, the diverse range of Ni/Co mass ratios (1:0, 2:1, 1:1, 1:2, 0:1) were prepared via the co-impregnation method. The synthesized materials were characterized through X-ray powder diffraction (XRD), N2 adsorption/desorption, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), dot mapping analysis, Dispersive X-ray Spectroscopy (EDS), Dynamic light scattering (DLS), temperature-programmed reduction analysis (H2-TPR), H2 temperature programmed desorption (H2-TPD), and thermogravimetric analysis (TGA). Based on findings, the mullite support has the high potential to act as appropriate support to immobilize metal particles with good distribution, which is beneficial for BR, especially in terms of coke and sintering resistivity. Among synthesized catalysts, 10%Ni-10%Co/mullite showed the highest CH4, CO2 conversions, and H2 yield at 800°C.