Optimizing low-temperature CO2 methanation through frustrated Lewis pairs on Ni/CeO2 catalysts

Abstract

The promising realm of carbon dioxide (CO2) conversion offers a compelling avenue to advance environmental sustainability. This study introduces a novel approach by utilizing frustrated Lewis pairs (FLPs) for efficient low-temperature CO2 methanation. Through a tailored ammonium bicarbonate (AB) precipitation method, we engineered Ni/CeO2 catalysts abundant in FLPs. Various morphologies, including aggregated flakes, broom-like structures, and irregular granules, were achieved by modulating the AB-to-cerium molar ratio. The distinctive broom-like Ni/(0.06AB)CeO2 catalyst, comprised of nanorods with abundant FLPs, exhibited outstanding low-temperature CO2 methanation performance: 67.5 % CO2 conversion, 99.6 % CH4 selectivity, and 0.27 s−1 CO2 turnover frequency (TOFCO2) at 240 °C, with excellent stability in a 100-h test at 300 °C. Furthermore, leveraging in-situ DRIFTS and in-situ Raman techniques, and DFT study, we unraveled CO2 hydrogenation pathways and found a dual interplay of CO and formate pathways in the low-temperature methanation over Ni/(0.06AB)CeO2 catalyst.