The effects of size and active site structure on catalytic activity were deeply investigated in air oxidation of benzyl alcohol over a series of Ni₃Al-LDH (layered double hydroxides)-supported Au_n nanocluster (NC) catalysts Au_n/LDH (n = 25, 38, ~127), obtained by modified electrostatic adsorption of atomically precise Au₂₅Capt₁₈, Au₃₈Capt₂₄ and Au_~127-Capt (Capt: captopril) NCs followed proper calcination. Detailed characterizations show that the Au₂₅/LDH, Au₃₈/LDH and Au_~127/LDH possess ultrafine Au NCs size of 1.2 ± 0.2, 1.4 ± 0.3 and 1.8 ± 0.5 nm, respectively, which are majorly dispersed on the edge sites of the small-sized LDH nanosheets (20–40 nm). All the catalysts exhibit excellent catalytic activities in air oxidation of benzyl alcohol without external base associated with the remarkable size- and active site structure-dependence. The catalyst Au₃₈/LDH shows the highest activity with TOF of 1884 h⁻¹, which can be attributable to the ultrafine bi-icosahedron structure Au₃₈ NCs and the strongest Au₃₈ NCs – Ni-OH (LDH) synergistic effect facilitating the activation of α-CH bond of benzyl alcohol over more negatively charged Au sites upon XPS, CO-DRIFTs and kinetic isotope studies. The findings of the size- and active site structure-dependence of supported Au_n cluster catalysts in the oxidation of benzyl alcohol provide important guiding principles for the rational design of supported Au_n cluster catalysts.

在一系列Ni ₃ Al-LDH（层状双氢氧化物）负载的Au _n纳米簇（NC）催化剂上，在苄醇的空气氧化中，深入研究了大小和活性位点结构对催化活性的影响。Au _n / LDH（n = 25，38，〜127）中，由原子精确的Au改性静电吸附得到₂₅上校₁₈，AU ₃₈上校₂₄和Au _〜127 -Capt（机长：卡托普利）的NC随后适当煅烧。详细特征表明，Au ₂₅ / LDH，Au ₃₈ / LDH和_Au〜127/ LDH分别具有1.2±0.2、1.4±0.3和1.8±0.5 nm的超细Au NCs尺寸，它们主要分散在小尺寸LDH纳米片（20-40 nm）的边缘部位。所有催化剂在苯甲醇的空气氧化中均表现出优异的催化活性，而没有外部碱，这与显着的尺寸和活性位点结构相关。Au ₃₈ / LDH催化剂在TOF为1884 h ^-1时表现出最高的活性，这归因于超细双二十面体结构的Au ₃₈ NCs和最强的Au ₃₈ NCs – Ni-OH（LDH）协同作用，促进了活化α-C的XPS，CO-DRIFT和动力学同位素研究显示，苄醇的H键在带更多负电荷的Au位上。负载的Au _n簇状催化剂在苯甲醇氧化中的尺寸和活性位点结构相关性的发现为合理设计负载的Au _n簇状催化剂提供了重要的指导原则。