Highly Stable CO 2 Methanation Catalyst Fabricated by Engineering Metal–Metal Oxide Interfaces of CoAlO x

ABSTRACT Preparation of a heterogeneous catalyst with ultra‐high catalytic stability and target product selectivity of > 99% at near thermodynamic equilibrium conversion is the ultimate goal to pursue in the catalysis field. Here, a CoAlO x catalyst is constructed for CO 2 methanation by precisely engineering metal–metal oxide interfaces. It shows CO 2 conversion of > 87% and CH 4 selectivity of > 99% within 3000 h at 350°C, 1 MPa and GHSV of 12 000 mL g −1 h −1 . Further prolonging of reaction time to 5000 h just slightly decreases CO 2 conversion to 77.5% without seriously affecting CH 4 selectivity. The CH 4 productivity approaches to 2463.6 mmol g −1 h −1 at GHSV of 375 000 mL g −1 h −1 , being superior to reported noble metal‐ and transition metal‐based catalysts. Such a catalytic performance stems from formation of Co 0 ‐CoO‐Al 2 O 3 microstructures with metallic Co 0 nanoparticles stably trapped in atomically intimate CoO‐Al 2 O 3 material. The CoO‐Al 2 O 3 interfaces enhance CO 2 adsorption and transformation into carbonates and/or bicarbonates, whereas metallic Co 0 promote H 2 dissociation and CO 2 hydrogenation. Technical and economic analyses show that CO 2 methanation could be profitable in places with abundant wind, photovoltaic, and other off‐grid powers, or when the green hydrogen price is < 1103.40 US$/t, which could help build sustainable energy system in the future.