(513ao) Synthesis of Fumed Silica Supported Ni and Cu Catalyst for Carbon Dioxide Conversion

Carbon dioxide is an undesired byproduct in almost all the energy production routes involving combustion of hydrocarbons or fossil fuels. CO₂ being one of the prominent greenhouse gas is understood to have a direct influence of the global environmental conditions, and in this regard many researchers are exploring the possible ways to convert CO₂ to hydrocarbons, or other chemicals to complete the carbon cycle. With an aim of so, CO₂ methanation has experienced a renewed research interest, especially because of its thermodynamic favorability under moderate conditions (temperature and pressure). CO₂ methanation can comprise of two reactions, reverse water gas shift (RWGS) and CO methanation.

In this study we investigate the synthesis of nickel and copper catalyst supported on silica for CO₂ conversion to methane. The activity and product selectivity and stability for methanation reaction on Ni/SiO₂ and Cu/SiO₂ catalysts have been evaluated using a flow reactor between 50ºC – 650ºC. The as-synthesized catalysts were characterized using XRD, SEM, TEM to understand the structural properties. In addition, the used catalysts after the reaction were characterized using similar techniques to evaluate the effect of reaction conditions on active phase and SiO₂ support. Catalyst consisting of 1%Ni on fumed-SiO₂ showed good activity for CO₂ conversion to CH₄ till 450ºC, thereafter CH₄ formation decreases and CO increases and remains the only product at 650ºC. The catalyst shows excellent stability without any deactivation till 2700 min of TOS at 650ºC. The other catalysts, 1%Cu on SiO₂ is also promising, however it was exclusively selective to CO and no trace of CH₄ was obtained.