Synthesis of core/shell nanocrystals with ordered intermetallic single-atom alloy layers for nitrate electroreduction to ammonia
Synthesis of core/shell nanocrystals with ordered intermetallic single-atom alloy layers for nitrate electroreduction to ammonia
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DOI：
10.1038/s44160-023-00258-x
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发表时间：
2023-07-01
期刊：
影响因子：
--
通讯作者：
Zhu, Huiyuan
中科院分区：
文献类型：
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作者：
Gao, Qiang;Yao, Bingqing;Zhu, Huiyuan
结构有序的金属间纳米晶体（NCs）和单原子催化剂（SACs）是两种新兴的可持续化学生产和能量转换的催化基序。然而，两者都有合成的局限性，这可能导致纳米碳或金属原子的聚集。单原子合金（SAAs）是在主金属中含有孤立的金属原子，由于单原子在主金属表面的热力学稳定性，可以克服聚集问题。本文报道了一种具有可调谐SAA层的Cu/CuAu核/壳纳米碳纳米管的直接液相合成方法。这种合成方法可以推广到其他Cu/CuM （M = Pt, Pd）体系，其中M原子被隔离在铜基体中。使用这种方法，可以控制铜表面上的SAAs密度，从而产生低密度和高密度的单原子。在铜基体中加入金引入了配体效应，优化了*NO3和*N的化学吸附。结果表明，高密度Cu/CuAu材料在电催化硝酸还原反应中对NH3具有较高的选择性，法拉第效率为85.5%，产率为8.47 mol h-1 g-1。这项工作通过创建具有SAA原子层的核/壳NCs，推进了原子精确催化位点的设计，为广泛的催化应用开辟了道路。良好定义的单原子合金（SAA）纳米晶体具有孤立的原子中心和可调谐的电子特性，但合成具有挑战性。本文报道了一种直接液相合成具有可调SAA层的Cu/CuAu核/壳纳米立方的方法。Cu/CuAu纳米材料对硝酸转化为氨具有很高的电催化活性。
Structurally ordered intermetallic nanocrystals (NCs) and single-atom catalysts (SACs) are two emerging catalytic motifs for sustainable chemical production and energy conversion. However, both have synthetic limitations which can lead to the aggregation of NCs or metal atoms. Single-atom alloys (SAAs), which contain isolated metal atoms in a host metal, can overcome the aggregation concern because of the thermodynamic stabilization of single atoms on host metal surfaces. Here we report a direct solution-phase synthesis of Cu/CuAu core/shell NCs with tunable SAA layers. This synthesis can be extended to other Cu/CuM (M = Pt, Pd) systems, in which M atoms are isolated in the copper host. Using this method, the density of SAAs on a copper surface can be controlled, resulting in both low and high densities of single atoms. Alloying gold into the copper matrix introduced ligand effects that optimized the chemisorption of *NO3 and *N. As a result, the densely packed Cu/CuAu material demonstrated a high selectivity toward NH3 from the electrocatalytic nitrate reduction reaction with an 85.5% Faradaic efficiency while maintaining a high yield rate of 8.47 mol h-1 g-1. This work advances the design of atomically precise catalytic sites by creating core/shell NCs with SAA atomic layers, opening an avenue for broad catalytic applications.Well-defined single-atom alloy (SAA) nanocrystals possess isolated atom centres and tunable electronic properties but are challenging to synthesize. Here, a direct solution-phase synthesis of Cu/CuAu core/shell nanocubes with tunable SAA layers is reported. The Cu/CuAu nanomaterial is highly active for the electrocatalytic conversion of nitrate into ammonia.