Atomically dispersed tungsten enhances CO tolerance in electrocatalytic hydrogen oxidation by regulating the 5d-orbital electrons of platinum
Xu Zhang, Peng Yu, Di Shen, Bin Cai, Tianyu Han, Ying Xie, Lei Wang
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 H 2 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 H 2 . 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. Utilizing atomically dispersed W sites to modulate the electronic structure of Pt can optimize the adsorption kinetics of hydrogen and CO, thereby promoting hydrogen oxidation activity and hydrogen-oxygen fuel cell performance even in H 2 /CO mixture containing 1000 ppm CO. • The Pt/W@NCNF featuring Pt nanoparticles and atomically dispersed W sites has been designed as a CO-tolerant HOR catalyst. • Incorporating atomically dispersed W sites modulates Pt-5d orbital electronic structure to optimize H 2 and CO adsorption. • It shows superior HOR activity and stability at H 2 /1000 ppm CO and enhanced PEMFC performance across various CO levels.