Alkaline Earth Metal-Induced Hydrogenation of the CaO-Captured CO₂ to Methane at Room Temperature

Abstract

CaO is promising to be widely used to capture CO2. The produced CaCO3 can be considered as solid CO2, which is also a plentiful, convenient, and useful carbon resource. Here, for the first time, we report that an alkaline earth metal can selectively induce the hydrogenation of the CaO-captured CO2 (namely, the produced CaCO3) to CH4 under room-temperature ball-milling conditions. The effects of ball-milling conditions and different catalysts on the methanation performance were studied. The results show that the CH4 yield can reach 56.1%, and the CH4 selectivity is 100%. When adding metal Ni, the CH4 yield can be further increased. The experimental and density functional theory calculation results indicate that the in situ formed metal hydride plays a key role in the process of methanation. This work provides a novel and energy-saving method to convert the metal oxide-captured CO2/carbonate to CH4 at room temperature.

Selective Conversion of the CaO-Captured CO2 to CH4 by Ni- and Hydrogen-Assisted Calcium Looping Processes in a Batch Reactor

“…Recently, there has been interest in the catalytic hydrogenation of carbonates to hydrocarbons. − According to the research by Rao et al, carbonate can be transformed into CH 4 at 823 K in the presence of the catalyst Co/CoO/CaO . They also reported that CaCO 3 could be hydrogenated to create C 1 –C 3 hydrocarbons in the temperature range of 573–873 K under atmospheric pressure using the catalysis of iron catalyst .…”