<br>MoO3/Ni(OH)2 的直接电催化甲醇氧化：利用相邻 Mo 和 Ni 的协同效应,Journal of the American Chemical Society

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MoO3/Ni(OH)2 的直接电催化甲醇氧化：利用相邻 Mo 和 Ni 的协同效应
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2023-12-01 , DOI: 10.1021/jacs.3c09399
Hui Cheng ₁ , Boheng Dong _{1,

2} , Qiong Liu ₁ , Fuxian Wang _{1,

3}

Affiliation

镍基材料作为甲醇氧化反应（MOR）催化剂已被广泛研究。 NiOOH的形成及其还原成Ni(OH) ₂通常被认为是甲醇氧化的重要步骤。然而，在这种间接途径中，质子耦合电子转移的效率从根本上受到从Ni(OH) ₂到NiOOH来回转变的速率的限制。在此，我们展示了 MoO ₃ /Ni(OH) ₂上的直接 MOR 途径，而不形成 NiOOH 介体。 MoO ₃ /Ni(OH) ₂在 1.52 V vs. RHE 下表现出 1000 mA cm ^–2的基准电催化 MOR 电流密度，具有接近 100% 的法拉第效率，优于所有最先进的 MOR 电催化剂。原位拉曼光谱证实，在MoO ₃ /Ni(OH) ₂上的电催化MOR过程中没有形成NiOOH。密度泛函理论计算表明MoO ₃ /Ni(OH) ₂中的Ni ²⁺作为甲醇吸附位点，而掺杂的Mo ⁶⁺在捕获去质子化的H·中起关键作用。受益于Mo-Ni的协同效应，CH ₂ O* → CHO* + H*过程的能垒显着降低，避免了NiOOH的形成并导致直接MOR。我们的研究揭示了一种不依赖于 NiOOH 形成的直接电化学 MOR 途径，并提供了一种调节 MOR 中间过程势垒的简便策略。

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Direct Electrocatalytic Methanol Oxidation on MoO3/Ni(OH)2: Exploiting Synergetic Effect of Adjacent Mo and Ni

Ni-based materials have been widely investigated as methanol oxidation reaction (MOR) catalysts. The formation of NiOOH and its reduction to Ni(OH)₂ are generally regarded as essential steps for methanol oxidation. However, in such an indirect route, the efficiency of proton coupled electron transfer is fundamentally limited by the rate of transition from Ni(OH)₂ to NiOOH back and forth. Herein we demonstrate a direct MOR pathway on MoO₃/Ni(OH)₂ without the formation of a NiOOH mediator. The MoO₃/Ni(OH)₂ exhibits a benchmark electrocatalytic MOR current density of 1000 mA cm^–2 at 1.52 V vs. RHE with a nearly 100% faradic efficiency, outperforming all the state of art MOR electrocatalysts. In-situ Raman spectroscopy confirms that NiOOH is not formed during the electrocatalytic MOR process on the MoO₃/Ni(OH)₂. Density functional theory calculations suggest that Ni²⁺ in MoO₃/Ni(OH)₂ serves as the methanol adsorption site while the doped Mo⁶⁺ plays a key role in capturing the deprotonated H·. Benefiting from the Mo–Ni synergistic effect, the energy barrier of the CH₂O* → CHO* + H* process is significantly reduced, avoiding the NiOOH formation and leading to the direct MOR. Our research unravels a direct electrochemical MOR pathway that does not rely on NiOOH formation and provides a facile strategy of regulating the intermediate process barrier for MOR.

更新日期：2023-12-01

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