Methanol steam reforming (MSR) is studied on a Pt
3Sn surface using the density functional theory (DFT). An MSR network is mapped out, including several reaction pathways. The main pathway proposed is CH
3OH + OH → CH
3O →
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Methanol steam reforming (MSR) is studied on a Pt
3Sn surface using the density functional theory (DFT). An MSR network is mapped out, including several reaction pathways. The main pathway proposed is CH
3OH + OH → CH
3O → CH
2O → CH
2O + OH → CH
2OOH → CHOOH → COOH → COOH + OH → CO
2 + H
2O. The adsorption strengths of CH
3OH, CH
2O, CHOOH, H
2O and CO
2 are relatively weak, while other intermediates are strongly adsorbed on Pt
3Sn(111). H
2O decomposition to OH is the rate-determining step on Pt
3Sn(111). The promotion effect of the OH group is remarkable on the conversions of CH
3OH, CH
2O and
trans-COOH. In particular, the activation barriers of the O–H bond cleavage (e.g., CH
3OH → CH
3O and
trans-COOH → CO
2) decrease substantially by ~1 eV because of the involvement of OH. Compared with the case of MSR on Pt(111), the generation of OH from H
2O decomposition is more competitive on Pt
3Sn(111), and the presence of abundant OH facilitates the combination of CO with OH to generate COOH, which accounts for the improved CO tolerance of the PtSn alloy over pure Pt.
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