Insight into the role of Fe on catalytic performance over the hydrotalcite-derived Ni-based catalysts for CO2 methanation reaction

Abstract

A series of Fe modified hydrotalcite-derived Ni-based catalysts (Ni3Fex-calc) were synthesized to evaluate the effect of Fe on CO2 methanation performance over Ni3-calc catalyst. The results showed that Ni3–Fe0.5-calc had superior catalytic activity with 78% CO2 conversion rate at 200 °C. The addition of moderate amount of Fe can effectively improve the reducibility, enrich the medium basic sites of Ni3-calc catalyst, and further facilitate the adsorption and activation of CO2. This resulted in the outstanding low-temperature CO2 methanation activity, as well as the enhanced resistance of carbon deposition. In-situ DRIFTS results indicated that the CO2 methanation reaction mechanism involved a progressive hydrogenation of carbonate and formate species to methane route. The formate species was the main intermediates during CO2 methanation. The introduction of Fe could significantly accelerate the hydrogenation rate of carbonates and formate species.