Construction of an inverse NiCoCeAl-LDO/Ni catalyst for effective CO2 methanation at low temperature

Abstract

Developing cost-effective CO₂ methanation catalysts that perform efficiently at low temperatures remains a significant challenge in enabling carbon-neutral energy cycles. Traditional catalysts often suffer from rapid deactivation due to unavoidable metal sintering and carbon deposition. In this study we constructed a novel inverse NiCoCeAl-LDO/Ni catalyst by in situ growth of layer dioxide (LDO) on a Ni substrate, which can effectively overcome these issues. The inverse configuration not only physically confines active Ni species but also creates rich oxide–metal interfaces that promote strong electronic oxide-metal interactions (EOMIs). Systematic characterization reveals that Co doping facilitates the reduction of Ni²⁺ to metallic Ni⁰, thereby increasing hydrogen dissociation sites and enhancing hydrogen spillover. Concurrently, the Ce³⁺/Ce³⁺ redox pairs generate abundant oxygen vacancies, which lower the activation barrier for both catalyst reduction and CO₂ hydrogenation. As a result, the optimized 3LDO/0.6Ni catalyst achieves exceptional low-temperature performance, with 97.4% CO₂ conversion and almost 100% CH₄ selectivity at 260 °C under 2 MPa. In situ DRIFTS studies identify the formate pathway as the dominant reaction mechanism. Remarkably, the catalyst exhibits outstanding stability over 100 h on stream with no detectable decline in activity or selectivity. This work provides a fundamental understanding of interface engineering in inverse catalysts and offers a viable strategy for designing highly active, stable, and low-temperature CO₂ methanation systems.