Deciphering the valence effect of platinum single atom catalyst on ceria for methane decomposition

Platinum single atom catalyst (Pt₁) supported by ceria (CeO₂) exhibits high activity toward methane (CH₄) decomposition. However, the valence state of Pt₁ active species remains unclear due to the dynamic changes of the geometric and electronic structures of Pt₁/CeO₂ under reaction condition. Herein, we investigate the full reaction pathways of CH₄ dissociation on Pt₁-adsorbed (Pt₁-ads) and Pt₁-substituted (Pt₁-sub) CeO₂ surfaces in different valances (<italic>n</italic> = 0–4). Nonlinear scaling relations in volcano shapes are found for the apparent (<italic>E</italic>_a,app) and rate-determining energy barriers (<italic>E</italic>_a,rds) correlated to the C/H adsorption energy (<italic>E</italic>_ad). Microkinetic modeling validates the most favorable valences of Pt₁-ads and Pt₁-sub for CH₄ decomposition are +1 and +4, respectively, which is in good agreement with the experimental observations. This study provides rational understanding of the valence effect of Pt₁/CeO₂ in CH₄ activation.