Ultrasmall Au nanoclusters have been proven to effectively enhance the catalytic performance of NiFe layered double hydroxides (NiFe-LDHs) toward oxygen evolution reaction (OER), yet the surface ligand effect of the Au nanoclusters still remains elusive. Herein, a systematic study is reported to examine the OER performance of NiFe-LDHs supported atom-precise all alkynyl-protected [Au₂₈(^tBuC≡C)₁₇]⁻ nanoclusters (Au₂₈-Alkynyl in short) and thiolate-protected Au₂₈(TBBT)₂₀ (TBBT = 4-tert-butylbenzenethiol) counterparts (Au₂₈-Thiolate in short). The Au₂₈-Alkynyl cluster has characteristic absorbance feature, and its composition is verified by mass spectrometry. It possesses a drastically different structure from the reported mixed ligand protected Au₂₈ nanoclusters. Interestingly, the NiFe-LDHs loaded with Au₂₈-Alkynyl exhibited a superior OER performance than the sample loaded with Au₂₈-Thiolate under the same conditions, evidenced by a smaller overpotential of 205 mV at the current density of 10 mA·cm⁻² and a lower Tafel slope value of 41.0 mV·dec⁻¹ in 1 mol·L⁻¹ KOH. Such excellent performance is attributed to the interfaces created between the NiFe-LDHs and the Au nanoclusters, as density functional theory calculations reveal that more significant charge transfer occurs in Au₂₈-Alkynyl/NiFe-LDHs catalyst, and more importantly, the energy barrier of the potential-determining step in the OER process for Au₂₈-Alkynyl/NiFe-LDHs is much lower than that of Au₂₈-Thiolate/NiFe-LDHs hence favors the electrocatalytic reaction.

Graphical abstract

中文翻译：

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锚定在 NiFe-LDH 上的全炔基保护的 Au28 纳米团簇的异质界面促进析氧反应：揭示配体效应的一个案例

超小的Au纳米团簇已被证明可以有效增强NiFe层状双氢氧化物（NiFe-LDHs）对析氧反应（OER）的催化性能，但Au纳米团簇的表面配体效应仍然难以捉摸。本文报道了一项系统研究，以检查 NiFe-LDHs 负载的原子精确的全炔基保护的 [Au ₂₈ ( ^t BuC≡C) ₁₇ ] ⁻纳米团簇（简称 Au ₂₈ -炔基）和硫醇盐保护的 Au 的OER 性能。 ₂₈ (TBBT) ₂₀ (TBBT = 4-叔丁基苯硫醇) 对应物（简称Au _{28 -硫醇盐）。}Au ₂₈ -炔基团簇具有特征吸光度特征，其组成通过质谱法验证。_{它具有与报道的混合配体保护的 Au 28}纳米团簇截然不同的结构。有趣的是，在相同条件下，负载Au ₂₈ -Alkynyl的NiFe-LDH表现出比负载Au _{28 -硫醇盐的样品更优异的OER性能，这通过在10 mA·cm} ^-2的电流密度下更小的205 mV的过电位来证明。在1 mol·L ^-1 KOH中塔菲尔斜率较低，为41.0 mV·dec ^-1。这种优异的性能归因于 NiFe-LDHs 和 Au 纳米团簇之间形成的界面，密度泛函理论计算表明，Au 28 -Alkynyl _/ NiFe-LDHs 催化剂中发生了更显着的电荷转移，更重要的是， Au ₂₈ -Alkynyl/NiFe-LDHs的 OER 过程中的电位决定步骤远低于 Au ₂₈ -硫醇盐/NiFe-LDHs，因此有利于电催化反应。

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