Atomically dispersed tungsten enhances CO tolerance in electrocatalytic hydrogen oxidation by regulating the 5d-orbital electrons of platinum

Abstract

The susceptibility of Pt catalyst surfaces to carbon monoxide (CO) poisoning in anodic hydrogen oxidation reaction (HOR) has been a critical constraint on the development of proton exchange membrane fuel cells (PEMFCs). Effectively regulating the electronic structure of Pt to enhance CO resistance is crucial for developing high-performance catalysts with robust anti-poisoning capabilities. Herein, the Pt/W@NCNF featured by Pt nanoparticles and atomical dispersed tungsten (W) sites on N-doped carbon nanofibers is developed for CO tolerance HOR catalyst. The presence of W enables the electron transfer from Pt, which promotes electron rearrangement in the Pt-5d orbitals. It not only optimizes the adsorption of H∗ and CO∗ on Pt, but also the OH∗ intermediates adsorbed on the W sites oxidize the CO∗ adsorbed on Pt, thereby retaining more active sites for H₂ adsorption and oxidation. The HOR exchange current density of Pt/W@NCNF reaches 1.35 times that of commercial Pt/C, and the limiting current density decreases by only 3.4% after introducing 1000 ​ppm CO in H₂. Notably, the Pt/W@NCNF-based PEMFCs deliver markedly superior performance across a range of CO concentrations. The present study demonstrates that electronic modulation of Pt is an effective strategy for simultaneously achieving resistance to CO and promoted HOR activity.