Fe3O4 界面硫化物活性物质和中间体的原位识别在大电流密度下用于超稳定碱性析氧,ACS Catalysis

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Fe3O4 界面硫化物活性物质和中间体的原位识别在大电流密度下用于超稳定碱性析氧
ACS Catalysis ( IF 11.3 ) Pub Date : 2022-03-28 , DOI: 10.1021/acscatal.2c01090
Qianqian Ji ₁ , Yuan Kong ₂ , Hao Tan ₁ , Hengli Duan ₁ , Na Li ₁ , Bing Tang ₁ , Yao Wang ₁ , Sihua Feng ₁ , Liyang Lv ₁ , Chao Wang ₁ , Fengchun Hu ₁ , Wenhua Zhang ₁ , Liang Cai ₃ , Wensheng Yan ₁

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过渡金属硫化物被研究作为碱性介质中析氧反应（OER）的有前途的电催化剂；然而，真正的活性物种仍然难以捉摸，从硫化物重建的羟基氧化物的开发在低应用电位下提供稳定的大电流密度是一个巨大的挑战。在这里，我们报道了一种协同混合催化剂，由 Co ₉ S ₈和 Fe ₃ O ₄的纳米级异质结构组成，在 1.0 M KOH 中在 500 mA cm ^-2下仅表现出 350 mV 的低电位和 120 小时的记录稳定性. 电压依赖性软 X 射线吸收光谱 (XAS) 和操作拉曼光谱表明，初始 Co ₉S ₈ @Fe ₃ O ₄被重构为CoOOH/CoO _x @Fe ₃ O ₄并进一步完成CoOOH@Fe ₃ O ₄。Operando XAS 和电子显微镜成像分析表明，完全重建的 CoOOH 充当活性物质，Fe ₃ O ₄组分阻止了 CoOOH 的聚集。操作红外光谱表明钴超氧化物物质 (*OOH) 在 OER 过程中是活性中间体。密度泛函理论计算表明*OOH的形成是OER和CoOOH@Fe _{3的速率决定步骤}O ₄对OER表现出较低的能垒。我们的研究结果提供了对用于碱性 OER 的硫化物电催化剂的动态表面结构演变的深入理解，并为设计用于稳定大电流密度的优秀纳米催化剂提供了见解。

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Operando Identification of Active Species and Intermediates on Sulfide Interfaced by Fe3O4 for Ultrastable Alkaline Oxygen Evolution at Large Current Density

Transition-metal sulfides are investigated as promising electrocatalysts for oxygen evolution reaction (OER) in alkaline media; however, the real active species remain elusive and the development of oxyhydroxides reconstructed from sulfides delivering stable large current density at low applied potentials is a great challenge. Here, we report a synergistic hybrid catalyst, composed of nanoscale heterostructures of Co₉S₈ and Fe₃O₄, that exhibits only a low potential of 350 mV and record stability of 120 h at the 500 mA cm^–2 in 1.0 M KOH. Voltage-dependent soft X-ray absorption spectroscopy (XAS) and Operando Raman spectroscopy demonstrate that the initial Co₉S₈@Fe₃O₄ is reconstructed into CoOOH/CoO_x@Fe₃O₄ and further to complete CoOOH@Fe₃O₄. Operando XAS and electron microscopy imaging analyses reveal that the completely reconstructed CoOOH acts as active species and Fe₃O₄ components prevent the aggregation of CoOOH. Operando infrared spectroscopy indicates cobalt superoxide species (*OOH) as the active intermediates during the OER process. Density functional theory calculations demonstrate the formation of *OOH as the rate-determining step of OER and CoOOH@Fe₃O₄ exhibits a lower energy barrier for OER. Our results provide an in-depth understanding of the dynamic surface structure evolutions of sulfide electrocatalysts for alkaline OER and insights into the design of excellent nanocatalysts for stable large current density.

更新日期：2022-03-28

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