Visualising coke-induced degradation of catalysts used for CO₂-reforming of methane with X-ray nano-computed tomography

The switch from a carbon-based to a hydrogen-based economy requires environmentally friendly methods for hydrogen production. CO₂-reforming of methane promises to be a greener alternative to steam-methane reforming, which accounts for the majority of hydrogen production today. For this dry process to become industrially competitive, challenges such as catalyst deactivation and degradation through coke formation must be better understood and ultimately overcome. While bulk characterisation methods provide a wealth of useful information about the carbon formed during coking, spatially resolved techniques are required to understand the type and extent of degradation of supported catalyst particles themselves under coking conditions. Here, lab-based X-ray nano-computed tomography, in conjunction with a range of complementary techniques, is utilised to understand the effects of the nickel-to-cobalt ratio on the degradation of individual supported catalyst particles. Findings suggest that a bimetallic system greatly outperforms monometallic catalysts, with the ratio between nickel and cobalt having a significant impact on the type and quantity of the carbon formed and on the extent of supported catalyst breakdown.