Ligand effect in surface atomic sites of group VI B transition metals on ultrathin Pt nanowires for enhanced oxygen reduction

• Published in: Nano research 2024-06, Vol.17 (6), p.5298-5304
• Main Authors: He, Yuwei, Chen, Yueguang, Wu, Renjie, Xiao, Zhihe, Li, Mengxian, Shi, Chunfeng, Wang, Leyu
• Format: Article
• Language: English
• Subjects: Atomic/Molecular Structure and Spectra; Bimetals; Biomedicine; Biotechnology; Catalysts; Chemical reduction; Chemistry and Materials Science; Chromium; Condensed Matter Physics; Electrodes; Fuel cells; Heavy metals; Leaching; Ligands; Materials Science; Membranes; Nanotechnology; Nanowires; Oxygen; Oxygen reduction reactions; Research Article; Transition metals
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-024-6528-2

Increasing the utilization efficiency of platinum is critical for advancing proton exchange-membrane fuel cells (PEMFCs). Despite extensive research on catalysts for the cathodic oxygen reduction reaction (ORR), developing highly active and durable Pt-based catalysts that can suppress surface dealloying in corrosive acid conditions remains challenging. Herein, we report a facile synthesis of bimetallic ultrathin PtM (M = Mo, W, and Cr) nanowires (NWs) composed of group VI B transition metal atomic sites anchored on the surface. These NWs possess uniform sizes and well-controlled atomic arrangements. Compared to PtW and PtCr catalysts, the PtMo 0.05 NWs exhibit the highest half-wave potential of 0.935 V and a mass activity of 1.43 A·mg Pt −1 . Remarkably, they demonstrate a remarkable 23.8-fold enhancement in mass activity compared to commercial Pt/C for ORR, surpassing previously reported Pt-based catalysts. Additionally, the PtMo NWs cathode in membrane electrode assembly tests achieves a remarkable peak power density of 1.443 W·cm −2 (H 2 -O 2 conditions at 80 °C), which is 1.09 times that of commercial Pt/C. The ligand effect in the bimetallic surface not only facilitates strong coupling between Mo (4d) and Pt (5d) atomic orbitals to hinder atom leaching but also modulates the d-states of active site, significantly optimizing the adsorption of key oxygen ( ⋆ O and ⋆ OH) species and accelerating the rate-determining step in ORR pathways.