Atomically Dispersed Zn and Ir Synergistic Modulation of Substrate and Active Sites for High‐Performance Ammonia Oxidation

作者：Qikai Shen, Chencheng Dai, Yuan Liu, Yuwei Zhang, Pengfei Song, Pinxian Xi, Shibo Xi, Adrian C. Fisher, Kamal Elouarzaki, Zhichuan J. Xu · 发表于：Angewandte Chemie International Edition · 年份：2025 · DOI：10.1002/anie.202513465 · 被引用次数：11 · 研究领域：Ammonia Synthesis and Nitrogen Reduction、Advanced Photocatalysis Techniques、Catalytic Processes in Materials Science

Abstract A rationally designed, bifunctional ammonia‐oxidation catalyst spatially decouples NH 3 activation and *OH adsorption to overcome the intrinsic trade‐off of single‐component systems. Atomically dispersed Zn single atoms in an N,O‐doped carbon support (Zn 1 /NOC) serve as dedicated *OH‐adsorption sites, while Ir‐modulated Pt(100) nanocubes selectively activate NH 3 . Comprehensive structural characterization (AC HAADF‐STEM, XPS, XANES, EXAFS) confirms Zn‐N 3 O 3 coordination and atomically isolated Zn centers. Electrochemical‐kinetic analysis, mechanistic spectroscopy, and DFT calculations reveal that Zn 1 /NOC lowers the *OH‐adsorption energy by 0.84 eV (to −0.98 eV versus −0.14 eV on Pt), facilitating the dehydrogenation steps and reducing surface poisoning. Simultaneously, traces of stabilized Ir 4+ ‐decorated Pt cubes enhance NH 3 dissociation kinetics to form N 2 . The catalyst demonstrates a specific activity of 3.80 mA cm −2 PGMs , exceeding the state‐of‐the‐art benchmarks. When deployed in a membrane‐electrode‐assembly direct ammonia fuel cell, the catalyst achieves a maximum current density of 200 mA cm −2 and a peak power density of 18 mW cm −2 , representing a significant improvement over previously reported systems, with ∼250% increase over Pt np –C || Pt/C and more than double monofunctional systems. This work demonstrates a generalizable strategy for engineering spatially decoupled active sites in multistep electrochemical reactions, paving the way for h...