NiFe LDHs的微晶化和晶格收缩增强水电催化氧化,Carbon Energy

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NiFe LDHs的微晶化和晶格收缩增强水电催化氧化
Carbon Energy ( IF 19.5 ) Pub Date : 2022-06-13 , DOI: 10.1002/cey2.215
Zhicheng Zheng ₁ , Dan Wu ₁ , Gen Chen ₁ , Ning Zhang ₁ , Hao Wan ₂ , Xiaohe Liu _{1,

2} , Renzhi Ma ₃

Affiliation

晶格氧介导的机制被认为是 NiFe 层状双氢氧化物 (LDHs) 电化学催化析氧反应 (OER) 的合理机制。使用葡萄糖酸钠通过简单的一步法合成了具有明显晶格收缩和微晶化的 NiFe LDH。晶格收缩归因于葡萄糖酸钠中的碳和NiFe LDH中的铁的相互作用。^{具有优化的微晶化和晶格收缩的 NiFe LDH 在 10 mA cm -2}的电流密度下表现出 217 mV 的低过电位，在100 mA cm ^-2的高电流密度下表现出出色的 20 小时耐久性. 结果表明，收缩的金属-氧键可以提高活性位点的内在活性，而微晶化促进了单位面积上活性位点数量的增加。不同计时电位下氧元素表征和电阻的化学环境证实了晶格氧元素确实参与了OER的过程，支持了NiFe LDH的晶格氧介导机制。密度泛函理论计算表明，收缩的金属-氧键降低了中间产物的吸附能垒，从而提高了内在催化活性。

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Microcrystallization and lattice contraction of NiFe LDHs for enhancing water electrocatalytic oxidation

The lattice-oxygen-mediated mechanism is considered as a reasonable mechanism for the electrochemical catalytic oxygen evolution reaction (OER) of NiFe layered double hydroxides (LDHs). A NiFe LDH with distinct lattice contraction and microcrystallization was synthesized via a simple one-step method using sodium gluconate. The lattice contraction is attributed to the interaction of carbon in sodium gluconate and iron in NiFe LDH. The NiFe LDH with optimized microcrystallization and lattice contraction shows a low overpotential of 217 mV at a current density of 10 mA cm⁻² and excellent durability of 20 h at a high current density of 100 mA cm⁻². The results revealed that a contractive metal–oxygen bond could boost the intrinsic activity of active sites and the microcrystallization promotes an increase in the number of active sites in terms of unit area. The chemical environment of oxygen elemental characterization and resistance at different chronopotentiometry times confirm that the lattice oxygen element is indeed involved in the process of OER, supporting the lattice-oxygen-mediated mechanism of NiFe LDH. Density functional theory calculations reveal that contractive metal–oxygen bonds induced a reduction of the adsorption energy barrier of intermediate products, thus improving the intrinsic catalytic activity. The special characteristics of microcrystallization and lattice contraction of NiFe LDH provide a strategy to improve both the number and the intrinsic activity of active sites in a versatile manner.

更新日期：2022-06-13

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