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Iron substitution enabled lattice oxygen oxidation and cation leaching for promoting surface reconstruction in electrocatalytic oxygen evolution
Journal of Colloid and Interface Science ( IF 9.4 ) Pub Date : 2023-11-15 , DOI: 10.1016/j.jcis.2023.11.080
Weiwei Yang 1 , Yu Bai 1 , Lin Peng 2 , Meixiu Qu 2 , Zhenhua Wang 2 , Kening Sun 2
Affiliation  

The low-cost transition metal oxides have drawn widespread interest as alternatives to noble metal-based electrocatalysts for oxygen evolution reaction (OER). Transition metal oxides usually undergo surface reconstruction during electrochemical reaction to form the actual active species. However, in-depth understanding and regulating of the surface reconstruction of active phases for oxides in OER remains an onerous challenge. Herein, we report a simple Fe element substitution strategy to facilitate the surface reconstruction of spinel oxide NiCr2O4 to generate active (oxy)hydroxides. The activated Fe-doped NiCr2O4 (Act-Fe-NCO) exhibits a lower OER overpotential of 259 mV at 10 mA cm−2 than activated NiCr2O4 (Act-NCO, 428 mV), and shows excellent stability for 120 h. The electrochemically activated CV measurement and nanostructure characterizations reveal that Fe substitution could promote the consumption of lattice oxygen during electrochemical activation to induce the leaching of soluble Cr cations, thereby facilitating the reconstruction of remaining Ni cations on the surface into (oxy)hydroxide active species. Moreover, theoretical calculations further demonstrate that the O 2p band center of NiCr2O4 moves towards the Fermi level due to Fe substitution, thus promoting lattice oxygen oxidation and providing greater structural flexibility for surface reconstruction. This work shows a promising way to regulate the surface reconstruction kinetics and OER electrocatalytic activity of transition metal oxides.

中文翻译:


铁取代使晶格氧氧化和阳离子浸出能够促进电催化析氧中的表面重建



低成本的过渡金属氧化物作为析氧反应 (OER) 贵金属基电催化剂的替代品引起了广泛关注。过渡金属氧化物通常在电化学反应过程中进行表面重构,以形成实际的活性物质。然而,深入了解和调控 OER 中氧化物活性相的表面重建仍然是一项艰巨的挑战。在此,我们报道了一种简单的 Fe 元素取代策略,以促进尖晶石氧化物 NiCr2O4 的表面重建以产生活性(氧)氢氧化物。活化的 Fe 掺杂 NiCr2O4 (Act-Fe-NCO) 在 10 mA cm-2 时表现出比活化的 NiCr2O4 (Act-NCO, 428 mV) 低 259 mV 的 OER 过电位,并在 120 小时内表现出优异的稳定性。电化学活化的 CV 测量和纳米结构表征表明,Fe 取代可以促进电化学活化过程中晶格氧的消耗,以诱导可溶性 Cr 阳离子的浸出,从而促进表面残留的 Ni 阳离子重建为(氧)氢氧化物活性物质。此外,理论计算进一步表明,由于 Fe 取代,NiCr2O4 的 O 2p 能带中心向费米能级移动,从而促进晶格氧氧化,为表面重构提供更大的结构灵活性。这项工作展示了一种很有前途的方法来调节过渡金属氧化物的表面重建动力学和 OER 电催化活性。
更新日期:2023-11-15
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