Pt@Au nanorods uniformly decorated on pyridyne cycloaddition graphene as a highly effective electrocatalyst for oxygen reduction.

Preparing metal-supported graphene nanocomposites is both interesting and challenging because of their well-defined morphologies and have potential application for oxygen reduction reaction (ORR). Here, we present an easy approach to synthesizing a novel hybrid material composed of Pt@Au nanorods (NRs) uniformly dispersed on the pyridyne cycloaddition of graphene (Pt@Au-PyNG), and the material serves as a high-performance catalyst for ORR. This hybrid electrocatalyst significantly decreases the use of Pt by using Pt dispersed on Au NRs and shows a markedly high activity toward ORR. The resulting Pt@Au-PyNG hybrid displayed comparable electrocatalytic activity and better stability than commercial Pt/C in alkaline solutions toward ORR. The hybrid effectively blocks CO formation to increase catalyst resistance to CO poisoning, thereby decreasing the amount of Pt needed. Free-energy diagrams for ORR on Pt@Au (111) through dissociative and associative mechanisms show that OH or O hydrogenation is the rate-limiting step based on DFT calculations.

The effect of CNTs on structures and catalytic properties of AuPd clusters for H2O2 synthesis.

The structures and catalytic properties of AuPd clusters supported on carbon nanotubes (CNTs) for H(2)O(2) synthesis have been investigated by means of density functional theory calculations. Firstly, the structures of AuPd clusters are strongly influenced by CNTs, in which the bottom layers are mainly composed of Pd and the top layers are a mix of Au and Pd due to the stronger binding of Pd than Au on CNTs. Especially, it is found that O(2) adsorption on the Pd/CNTs interfacial sites is much weaker than that on the only Pd sites, which is in contrast to transition metal oxide (for example TiO(2), Al(2)O(3), CeO(2)) supported metal clusters. Furthermore, Pd ensembles on the interfacial sites have far superior catalytic properties for H(2)O(2) formation than those away from CNT supports due to the changes in electronic structures caused by the CNTs. Therefore, our study provides a physical insight into the enhanced role of carbon supports in H(2)O(2) synthesis over supported AuPd catalysts.