Using DMH as a complexing agent for pulse electrodeposition of platinum nanoparticles towards oxygen reduction reaction

Due to the excellent intrinsic activity of platinum, developing a Pt-based oxygen reduction catalyst with both high performance and low loading is highly desirable but still challenging. How to improve the utilization of platinum-based materials has become one of the most critical issues. Herein, a synthesis strategy using the 5,5-dimethylhydantoin (DMH) as complexing agent is designed to synthesize the Pt catalyst via pulse electrodeposition. On the one hand, the platinum nanoparticles prepared by electrodeposition are exposed on the surface of support materials, which effectively avoids performance degradation caused by the coverage of binder and support. On the other hand, the strong coordination affinity between DMH and platinum ions significantly inhibits the electrodeposition process, resulting in a smaller size of platinum nanoparticles. The effect of plating composition and pulse plating parameters on the Pt/KB catalyst activity for oxygen reduction reaction (ORR) has been investigated. The deposited Pt nanoparticles show a face-centered cubic ( fcc ) crystal structure with a size ranging from 3 to 10 nm. The optimized Pt/KB catalyst exhibits an enhanced activity (i.e., a half-wave potential of 0.906 V) and stability in the acidic media, even with lower loading of platinum. Moreover, the vital role of the DMH in the pulse electrodeposition process is further verified by using linear sweep voltammetry and cyclic voltammetry.