Integration of Alloy Segregation and Surface Co?O Hybridization in Carbon-Encapsulated CoNiPt Alloy Catalyst for Superior Alkaline Hydrogen Evolution,Advanced Functional Materials

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Integration of Alloy Segregation and Surface Co?O Hybridization in Carbon-Encapsulated CoNiPt Alloy Catalyst for Superior Alkaline Hydrogen Evolution
Advanced Functional Materials ( IF 18.5 ) Pub Date : 2023-07-28 , DOI: 10.1002/adfm.202303833
Yangdan Pan ₁ , Junkuo Gao ₁ , Enjun Lv ₁ , Tongtong Li ₁ , Hui Xu ₂ , Lu Sun ₃ , Adeela Nairan ₁ , Qichun Zhang ₄

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Constructing an efficient alkaline hydrogen evolution reaction (HER) catalyst with low platinum (Pt) consumption is crucial for the cost reduction of energy devices, such as electrolyzers. Herein, nanoflower-like carbon-encapsulated CoNiPt alloy catalysts with composition segregation are designed by pyrolyzing morphology-controlled and Pt-proportion-tuned metal–organic frameworks (MOFs). The optimized catalyst containing 15% CoNiPt NFs (15%: Pt mass percentage, NFs: nanoflowers) exhibits outstanding alkaline HER performance with a low overpotential of 25 mV at a current density of 10 mA cm⁻², far outperforming those of commercial Pt/C (47 mV) and the most advanced catalysts. Such superior activity originates from an integration of segregation alloy and Co-O hybridization. The nanoflower-like hierarchical structure guarantees the full exposure of segregation alloy sites. Density functional theory calculations suggest that the segregation alloy components not only promote water dissociation but also facilitate the hydrogen adsorption process, synergistically accelerating the kinetics of alkaline HER. In addition, the activity of alkaline HER is volcanically distributed with the surface oxygen content, mainly in the form of Co_3dO_2p hybridization, which is another reason for enhanced activity. This work provides feasible insights into the design of cost-effective alkaline HER catalysts by coordinating kinetic reaction sites at segregation alloy and adjusting the appropriate oxygen content.

中文翻译：

碳包覆 CoNiPt 合金催化剂中合金偏析和表面 Co2O 杂化的集成，可实现优异的碱性析氢

构建具有低铂（Pt）消耗的高效碱性析氢反应（HER）催化剂对于降低电解槽等能源设备的成本至关重要。在此，通过热解形貌控制和 Pt 比例调整的金属有机框架（MOF）设计了具有成分偏析的纳米花状碳包覆 CoNiPt 合金催化剂。^{含有15％CoNiPt NFs（15％：Pt质量百分比，NFs：纳米花）的优化催化剂表现出出色的碱性HER性能，在10 mA cm -2}的电流密度下具有25 mV的低过电势，远远优于商业 Pt/C (47 mV) 和最先进的催化剂。这种优异的活性源于偏析合金和Co-O杂化的结合。纳米花状的分级结构保证了偏析合金位点的充分暴露。密度泛函理论计算表明，偏析合金成分不仅促进水解离，而且促进氢吸附过程，协同加速碱性HER的动力学。另外，碱性HER的活性随表面氧含量呈火山分布，主要以Co _3d O _{2p形式存在}杂交，这是增强活性的另一个原因。这项工作通过协调偏析合金的动力学反应位点并调整适当的氧含量，为设计具有成本效益的碱性析氢催化剂提供了可行的见解。

更新日期：2023-07-28

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