Ultrafine platinum particles anchored on porous boron nitride enabling excellent stability and activity for oxygen reduction reaction

Abstract

Improvement in the durability and activity of platinum (Pt)-based electrocatalyst for oxygen reduction reaction (ORR) is significant for the large-scale commercial applications of proton exchange membrane fuel cells. Herein, porous boron nitride (p-BN) was employed as functional support to stabilize Pt nanoparticles (NPs) and engineer its electronic structure. The as-prepared p-BN supported Pt NPs achieved excellent activity and stability for ORR with ~53 mV positive shift of half-wave potential compared to commercial 20 wt% Pt/C electrocatalyst and the electrochemical active surface area remained almost unaltered after 10,000 potential cycling durability tests. Density functional theory calculations clarified that electron-rich N and electron-deficient B play different roles when p-BN interacts with Pt. The transfer of electrons from electron-rich N atoms to Pt NPs and from Pt NPs to electron-deficient B atoms generate the occurrence of an electron donation-back donation process, which strengthened the binding between Pt NPs and p-BN and aided in optimization of the electronic structure of Pt. The results of this study clarified the interaction between p-BN and Pt catalyst and demonstrate that p-BN can effectively anchor Pt NPs to enhance the ORR performance by promoting easy electron transfer during catalytic reactions and preventing Pt NPs from aggregation in the process of ORR.