Abstract
Methane steam reforming was investigated over a Ni/NiAl2O4 catalyst at steam-to-carbon ratios (S/C) = 0.27–6.3 at 873 K. Increasing S/C ratios led to increasing, then stable, and finally decreasing, methane conversion, suggesting that the rate-determining step of reaction is a surface reaction between two species competing for the same active site.