Acquiring an effective CaO-based CO(2) sorbent and achieving selective methanation of CO(2)

CO(2) capture, utilization, and storage are promising strategies to solving the problems of superfluous CO(2) or energy shortage. Here, mechanochemical reduction of CO(2) by a MgH(2)/CaH(2) mixture was first performed, by which we achieve selective methanation of CO(2) and acquire an effective CaO-based CO(2) sorbent, simultaneously. The selectivity of methanation is near 100% and the yield of CH(4) reaches 30%. Four MgO and carbon-doped CaO-based CO(2) sorbents (MgO/CaO/C, MgO/2CaO/C, MgO/4CaO/C, and MgO/8CaO/C) were formed as solid products in these reactions. Among them, the MgO/4CaO/C sorbent shows high initial adsorption amount of 59.3 wt% and low average activity loss of 1.6% after 30 cycles. This work provides a novel, well-scalable, and sustainable approach to prepare an efficient inert additive-including CaO-based CO(2) sorbent and selectively convert CO(2) to CH(4) at the same time.