Improved Dual Function Materials for CO₂ Capture and In Situ Methanation

Abstract

Dual‐function materials (DFM) carry out both the CO2 purification and the reaction with H2, to produce CH4, over the same material and in the same equipment. While noble metals like Ru and Rh have traditionally been the focus of DFM research due to their catalytic activity at low temperatures, they are expensive. Therefore, there is strong interest in discovering more cost‐effective yet highly active catalysts. Herein, improved DFMs are developed by directly reducing Ni‐containing hydrotalcites, without prior air calcination, at moderate temperature. This method results in a high dispersion of Ni as well as in high amounts of small and reduced Ni crystallites with low interaction with the support, which are crucial for the improved behavior observed. The most remarkable and novel result is that these materials show superior CH4 productivity than previously reported DFMs. Under the five operation cycles evaluated, these DFMs exhibit a substantial increase in CO2 capture (1.76 mol kg−1 DFM) and CH4 productivity (0.98 mol kg−1 DFM), in the absence of O2 and water. In the presence of 4.5% O2, both CO2 adsorption and CH4 productivity decrease but they still outperform previous DFMs.