Local Oxidation Induced Amorphization of 1.5‐nm‐Thick Pt–Ru Nanowires Enables Superactive and CO‐Tolerant Hydrogen Oxidation in Alkaline Media

Abstract

Low‐dimensional amorphous metallic nanomaterials provide great possibility for creating high‐performance electrocatalysts owing to their conspicuous reacting merits derived from the flexible coordination structures, but remain extremely challenging in synthesis. Herein, this work reports a facile synthesis of carbon‐loaded amorphous 1.5‐nm‐thick Pt–Ru nanowires (NWs) through a local oxidation induced amorphization process. During annealing premade crystalline Pt–Ru NWs/C in air, a local‐oxidation of the oxyphilic Ru generates abundant random Ru–O bonds and disturbs the order bimetallic lattices. The as‐prepared amorphous Pt53Ru47 (a‐Pt53Ru47) NWs/C exhibits an extremely high activity (13.7 A mg−1 at 25 mV overpotential) and an excellent CO‐tolerance for alkaline hydrogen oxidation reaction (HOR) electrocatalysis, drastically outperforming the crystalline counterpart and commercial benchmarks. Mechanism studies indicate the Pt–Ru bimetallic effects as well as the rich disordered “Pt–Ru–O” and/or “Pt–O–Ru” atomic heterojunctions can weaken the *H binding energy and inversely strengthen the *OH adsorption, thus promoting the alkaline HOR kinetics. More uniquely, the small interatomic spaces derived from the disordered bond nets present a H2/*H‐selected permeability, which spatially obstruct the relatively larger CO molecules to poison the internal catalytic sites during HOR. The CO‐shielded internal catalytic sites and the enriched surface *OH jointly upgrade the CO‐tolerance of the a‐Pt53Ru47 NWs/C catalysts.

Breaking Surface Atomic Monogeneity of Rh2P Nanocatalysts by Defect‐Derived Phosphorus Vacancies for Efficient Alkaline Hydrogen Oxidation

“…Recent reports on alkaline HOR catalysts suggest that enhancing the OHBE can accelerate the rate-determined Volmer step through a bifunctional mechanism. This strategy has guided the successful design of highly efficient catalysts such as PtRu [52,53] and Pt/Ni(OH) 2 . [11] However, an excessively high OHBE can lead to active site poisoning and the dissociated adsorption of H 2 by oxygenated spectators, as suggested by the DFT calculation results in this work (Figure 1).…”

Balancing the Binding of Intermediates Enhances Alkaline Hydrogen Oxidation on D-Band Center Modulated Pd Sites

“…The peaks of PdCo/NC behaved in a negative shift compared to those of Co/NC, once again telling the Co received the electrons from the donator of Pd. The Pd sites with a lack of electrons may not very conducive to the adsorption of *H, which in turn leads to a weakening of the HBE . The N 1s spectrum of Figure S9b features three peaks located at 398.3, 400.6, and 401.6 eV, which belong to pyridinic N, pyrrolic N, and graphitic N bonds, with a relative content of 32.2%, 45.5%, and 22.2%, respectively.…”

CO-Tolerant Hydrogen Oxidation Electrocatalysts for Low-Temperature Hydrogen Fuel Cells

“…In subsequent experiments, these porous metal-oxide-coated Ru-based catalysts exhibited improved CO tolerance and robust stability. Xie et al also reported amorphous Pt–Ru nanowires (NWs) in which the small interatomic spaces derived from the disordered bond nets present an H 2 -selective permeability, which spatially obstructs the relatively larger CO molecules to poison the catalytic sites during HOR …”

“…Xie et al also reported amorphous Pt−Ru nanowires (NWs) in which the small interatomic spaces derived from the disordered bond nets present an H 2 -selective permeability, which spatially obstructs the relatively larger CO molecules to poison the catalytic sites during HOR. 68 Compared with mainstream electrooxidation and weakening adsorption strategies, such a blocking CO diffusion strategy is essentially independent of the working potential and regulation of the adsorption ability of HOR catalysts, which may play a more important role in developing new types of CO-tolerant HOR electrocatalysts or be combined with the mainstream strategies to synergistically promote CO tolerance. Although there are still some challenges that need to be overcome, without a doubt, this strategy holds great application potential.…”