A series of hierarchically structured hybrids Ni_xMg_3-xAl-LDH/rGO (LDH: layered double hydroxides, x = 1, 1.5 and 2, rGO: reduced graphene oxide) supported atomically precise Au_n (n = 25, 38 and 127) nanoclusters (NCs) catalysts Au_n/Ni_xMg_3-xAl-280 were firstly prepared via a double pH-controlled electrostatic adsorption method using captopril-capped Au_n NCs as precursors followed proper calcination. Detailed characterizations show that the as-obtained hierarchically structured Au_n NCs catalysts possess the nanosheet array-like structure formed by the LDHs nanosheets (∼55–70 × 10 nm) interdigitated vertically grown on the both sides of rGO layers, and Au_n NCs with size of 1.0–1.9 nm are mainly dispersed on the edge and cross-linking sites of LDH/rGO hybrid. All the hierarchically structured Au_n NCs catalysts exhibit excellent catalytic activity for the solvent-free oxidation of benzyl alcohol without additional base, and the activities show a volcanic trend with increasing Ni/Mg ratios and gradually decrease with the increased Au atomicities in Au_n clusters. The highest TOF value of 5118 h⁻¹ for the Au₂₅/Ni_1.5Mg_1.5Al-280 can be ascribed to the smallest Au₂₅ NCs containing the Au⁰/Au^δ+-Ni²⁺/Mg²⁺–OH interface with the highest Au^δ+/(Au⁰ + Au^δ+) ratio, and the strongest Au₂₅−LDH/rGO synergistic interaction along with hierarchical nanosheet array-like structure facilitating the transmission and diffusion of the reactants. The present work provides a new idea for preparing the hierarchically structured LDH/rGO hybrid supported metal nanoclusters catalysts with high-performance for various catalytic applications.

一系列分层结构的混合 Ni _x Mg _3-x Al-LDH/rGO（LDH：层状双氢氧化物，x  = 1、1.5 和 2，rGO：还原氧化石墨烯）支持原子精确的 Au _n（n  = 25、38 和127) 纳米团簇 (NCs) 催化剂 Au _n /Ni _x Mg _3-x Al-280 首先通过双 pH 控制静电吸附法制备，使用卡托普利封端的 Au _n NCs 作为前体，然后进行适当的煅烧。详细的表征表明，所获得的分层结构的 Au _nNCs催化剂具有由在rGO层两侧垂直生长的LDHs纳米片（~55-70×10 nm）形成的纳米片阵列状结构，尺寸为1.0-1.9 nm的Au _n NCs主要分散在LDH/rGO杂种的边缘和交联位点。所有分级结构的 Au _n NCs 催化剂在不添加碱的情况下对苯甲醇的无溶剂氧化表现出优异的催化活性，并且随着 Ni/Mg 比的增加，活性呈现火山趋势，随着 Au _n簇中 Au 原子数的增加而逐渐降低. Au ₂₅ /Ni _1.5 Mg _1.5的最高TOF值为5118 h ^-1Al-280 可以归因于最小的 Au ₂₅ NCs，其包含 Au ⁰ /Au ^δ+ -Ni ²⁺ /Mg ²⁺ -OH 界面，具有最高的 Au ^δ+ /(Au ⁰  + Au ^δ+ ) 比率，并且最强的Au ₂₅ -LDH / rGO协同相互作用以及分层纳米片阵列状结构促进反应物的传输和扩散。本工作为制备用于各种催化应用的高性能分层结构的 LDH/rGO 杂化负载金属纳米团簇催化剂提供了新思路。