<br>镍基磷酸盐的析氧活性及其电子轨道的影响。,Nanoscale Advances

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镍基磷酸盐的析氧活性及其电子轨道的影响。
Nanoscale Advances ( IF 4.6 ) Pub Date : 2024-12-09 , DOI: 10.1039/d4na00794h
Yuuki Sugawara ₁ , Yuto Nakase ₁ , Gopinathan M Anilkumar _{1,

2} , Keigo Kamata ₃ , Takeo Yamaguchi ₁

Affiliation

金属磷酸盐型化合物已用于多种应用，其独特的化学性质最近为它们用作催化剂开辟了途径。金属磷酸盐以前已证明对电化学水分解中的阳极析氧反应（OER）具有显着的电催化活性。然而，影响 Ni 基磷酸盐 OER 电催化的关键因素尚未得到充分探索。我们在此展示了镍（Ni）基磷酸盐-单斜 Ni3（PO4）2、单斜晶系 Ni2P2O7 和单斜晶系 Ni2P4O12 作为在碱性介质中表现出出色 OER 活性的示例材料。与传统的镍基氧化物（NiO）和磷化物（Ni2P）相比，这些镍基磷酸盐表现出优异的 OER 过电位。此外，它们的 OER 特异性活性超过了基于稀有金属的基准 IrO2，以及之前报道的由非贵金属组成的最先进的晶体电催化剂。长期耐久性测试表明，Ni3（PO4）2 即使在 1000 次重复电位循环后仍能保持其 OER 活性，同时保持其元素组成和拉曼光谱。为了了解镍基磷酸盐的优异 OER 活性，研究了其晶体内的原子构型。值得注意的是，在 Ni 基磷酸盐和 NiO 中都观察到 Ni-O 键长和 OER 过电位之间的明显相关性，即较短的 Ni-O 键长对 OER 非常有益。密度泛函理论（DFT）计算表明，Ni 基磷酸盐出色的 OER 活性是由其有利的电子轨道促进的，这增强了 Ni-O 键并改善了 OER 中间体在 Ni 位点上的吸附。采用表面板模型的 DFT 计算证实了这种机制，其中 OER 中间体在 Ni 基磷酸盐表面的吸附比在 NiO 表面上的能量更有利。因此，镍基磷酸盐是很有前途的 OER 电催化剂，本研究为进一步改进镍基电催化剂提供了重要指导。

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Oxygen evolution activity of nickel-based phosphates and effects of their electronic orbitals.

Metal phosphate-type compounds have been utilized in diverse applications, and their distinctive chemical properties have recently opened avenues for their use as catalysts. Metal phosphates have previously demonstrated significant electrocatalytic activity for the anodic oxygen evolution reaction (OER) in electrochemical water splitting. However, the critical factors influencing OER electrocatalysis on Ni-based phosphates have been insufficiently explored. We herein demonstrate nickel (Ni)-based phosphates-monoclinic Ni3(PO4)2, monoclinic Ni2P2O7, and monoclinic Ni2P4O12-as exemplary materials exhibiting outstanding OER activity in alkaline media. These Ni-based phosphates exhibit superior OER overpotentials compared to conventional Ni-based oxides (NiO) and phosphides (Ni2P). Additionally, their OER-specific activity surpasses that of the rare metal-based benchmark, IrO2, and previously reported state-of-the-art crystalline electrocatalysts comprising nonprecious metals. Long-term durability tests show that Ni3(PO4)2 maintains its OER activity even after 1000 repeated potential cycles while retaining its elemental composition and Raman spectrum. To understand the excellent OER activities of Ni-based phosphates, the atomic configurations within their crystals are examined. Remarkably, a clear correlation between Ni-O bond length and OER overpotentials is observed in both Ni-based phosphates and NiO, i.e., shorter Ni-O bond lengths are highly beneficial for the OER. Density functional theory (DFT) calculations revealed that the outstanding OER activities of Ni-based phosphates are facilitated by their favorable electronic orbitals, which strengthen the Ni-O bond and improve the adsorption of OER intermediates on Ni sites. This mechanism is substantiated by DFT calculations employing surface slab models, where the adsorption of OER intermediates on the surface of Ni-based phosphates is more energetically favorable than on the surface of NiO. Hence, Ni-based phosphates are promising OER electrocatalysts, and this study provides important guidelines to further improve Ni-based electrocatalysts.

更新日期：2024-12-09

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