Stable and selective syngas production from dry CH4-CO2 streams over supported bimetallic transition metal catalysts

•NiCo clusters below 45 nm and abundant oxygen vacancy sites of CeZrO2 are crucial.•Catalyst is resistant to carbon accumulation in a wide range of CH4-CO2 feeds.•Stable catalytic performance for 550 h is recorded at ambient pressure.•Stable operation is maintained for 60 h during reforming at 20 bar.•Accumulated carbon is 2-3 orders of magnitude lower compared to state-of-the-art.

Syngas production from CH4 and CO2 was investigated over bimetallic nickel-cobalt catalysts, promoted by a CeZrO2 redox component. The appropriate design of active sites responsible for methane and CO2 activation (bimetallic clusters below 45 nm, adjacent to oxygen vacancy sites of the CeZrO2 solid solution) enabled kinetic balancing of both reaction halves, producing catalysts that are highly resistant to carbon accumulation in a wide range of CH4-CO2 feed compositions. With the employed approach, carbon accumulation can be prevented over metal clusters that are 2-fold larger compared to state-of-the-art. By anchoring the active NiCo bimetallic and CeZrO2 redox components over a high surface area β-SiC carrier (3NiCo/CeZrO2/S catalyst), the redox promoter is diluted and sintering of bimetallic NiCo clusters is reduced. At ambient pressure, a remarkably stable catalytic performance for 550 h was recorded with a produced H2/CO ratio of 0.82, methane reforming rate of 0.18 mol/gcat h and negligible carbon accumulation. Stable operation is maintained for 60 h during reforming at 20 bar, producing syngas with a H2/CO ratio of 0.33. Importantly, accumulated carbon yield is 2-3 orders of magnitude lower compared to state-of-the-art. These results constitute a promising basis for the design of a prospective technology for CO-rich syngas production through CH4-CO2 reforming.

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