A comparison study of oxygen reduction on the supported Pt, Pd, Au monolayer on WC(0001)

• The catalytic activity of MML/WC(0001) toward ORR is comparatively studied.
• The AuML/WC(0001) exhibits the highest activity for ORR.
• The rate-determining step of ORR on AuML/WC(0001) is identified.
• The deactivation mechanisms of the PtML/WC(0001) and PdML/WC(0001) are addressed.

Using the first principles methods, the geometric and electronic structures of the metal monolayers supported on WC(0001) surfaces (MML/WC(0001) (M = Pt, Pd, and Au)) and their catalytic activity toward the oxygen reduction reaction (ORR) were comparatively studied. Both the kinetics and the density of states results demonstrated that the direct dissociation of O2 on all three MML/WC(0001) surfaces are almost impossible. Yet the barriers of the formation and dissociation of OOH on AuML/WC(0001) are much smaller than those on the PtML/WC(0001) and the PdML/WC(0001) surfaces, implying that the AuML/WC(0001) exhibits the highest catalytic activity for ORR via a combination of 2e− hydrogenation of O2 and 4e− dissociation of OOH. The rate-limiting step barrier of 0.83 eV for the hydrogenation of OH forming H2O is also comparable to that on the traditional Pt-based catalysts. The deactivation mechanism of PtML/WC(0001) and the performance of PdML/WC(0001) for ORR were identified. The present study is conductive to designing new efficient catalyst without using of the precious Pt for efficiently promoting ORR.

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