Solvothermal Doping of Lanthanum on Nanoscale Platinum Surfaces to Improve Oxygen Electroreduction Performance

摘要

Platinum (Pt) nanocatalysts, doped or alloyed with lanthanum (La), are promising candidates to promote the sluggish oxygen reduction reaction (ORR) kinetics. However, owing to the very low standard reduction potential of La3+(-2.38 V), most synthetic routes to reduce La are costly and complex. Therefore, the preparation of highly active bimetallic PtLa nanocatalysts by simple and low-cost synthesis methods is a challenging task. This work offers a feasible synthesis procedure for doping Pt nanocrystals with La in a simple solvothermal method. Elemental mapping and X-ray photoelectron spectroscopy measurements indicate that metallic La is doped on the Pt catalyst surfaces. The La-doped Pt nanocatalysts exhibit ORR mass activity of 0.49 A mg(Pt)(-1)at 0.9 V, which is 2.3 and 2.7 times compared to Pt nanocatalysts without La dopant and commercial Pt/C, respectively.