Network-like PtRu alloy nanounits for alkaline hydrogen oxidation

Hydrogen oxidation reaction (HOR) with alkaline solution is an important process for anion exchange membrane hydrogen-oxygen fuel cells, while it presents slow kinetics because it contains the coupling of adsorbed hydrogen (Had) and hydroxyl (OHad) species. Herein, PtRu alloy network-like structure with small size was prepared by a solution phase reduction route, which acts as an electrocatalyst for HOR. The presence of Ru changed the d-band center of Pt and so optimized the hydrogen bonding energy on Pt sites. At the same time, Ru species provides functional surface for the adsorption of OH species. The ultrathin size of the alloy units provides richness of exposed active sites for HOR. Benefited from the above factors, the obtained PtRu alloy with Pt:Ru ratio of 1:1 shows the optimized catalytic activity, providing an exchange current density of 1.93 mA cm-2, which is 2.7-fold and 1.5-fold of those for commercial Pt/C and pristine Pt catalyst, respectively. This work provides a new advanced electrocatalyst for alkaline HOR.

Automated summary

In this study, PtRu alloy electrocatalyst with small size and network-like structure was synthesized by a solution phase reduction route. The presence of Ru optimized the hydrogen bonding energy on Pt sites and provided functional surface for the adsorption of OH species. The ultrathin size of the alloy units significantly enhanced the catalytic activity for alkaline HOR.