Active and stable noble metal-free catalysts for the oxygen evolution reaction (OER) are essential for realizing large-scale hydrogen production using proton exchange membrane (PEM) electrolyzers. Herein, we discover that engineering the defect and morphology of spinel cobalt oxide allows us to obtain an optimal vacancy-rich Co₃O₄ hollow nanocube (V_o-Co₃O₄ HNC) catalyst with exceptional activity with a low overpotential of 265 mV at 10 mA cm⁻² and long-term stability for 130 h at 20 mA cm⁻² in acids, far exceeding those of the benchmark catalyst RuO₂ (390 mV and < 6 h) and most reported noble metal-based catalysts. Experimental and theoretical studies reveal that introducing oxygen defects effectively regulates the reaction mechanisms and introduction of an appropriate amount of defects significantly boosts both activity and stability by optimizing the adsorption/desorption energy barrier of intermediate species and suppressing the Co dissolution via the lattice oxygen mechanism pathway, respectively. The hollow cubic structure with highly exposed active sites and a large interfacial contact area further promotes the OER to enable high current density, as evidenced by finite element simulations. The application of V_o-Co₃O₄ HNCs in PEM electrolyzers steadily at 1 A cm⁻² achieves an energy consumption of 48.8 kW h kg⁻¹ H₂ and a projected cost of ∼US $ 0.976 kg⁻¹ H₂ (DOE's target: $2 kg⁻¹ of H₂ by 2026), suggesting the promise of using Earth-abundant materials for PEM water electrolysis.

中文翻译：

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用于安培级电流密度下质子交换膜水电解的缺陷平衡活性和稳定 Co3O4−x


用于析氧反应（OER）的活性和稳定的无贵金属催化剂对于使用质子交换膜（PEM）电解槽实现大规模制氢至关重要。在此，我们发现通过设计尖晶石钴氧化物的缺陷和形貌，我们可以获得最佳的富空位 Co ₃ O ₄ 空心纳米立方体 (V _o -Co ₃ O ₄ HNC) 催化剂，具有优异的活性，在 10 mA cm ⁻² 下具有 265 mV 的低过电势，并且在 130 小时内具有长期稳定性在酸中为 20 mA cm ⁻² ，远远超过基准催化剂 RuO ₂ （390 mV 和 < 6 h）和大多数报道的贵金属基催化剂。实验和理论研究表明，引入氧缺陷可以有效调节反应机理，通过优化中间物种的吸附/解吸能垒并通过晶格氧机制途径抑制Co溶解，引入适量的缺陷可以显着提高活性和稳定性。 ， 分别。有限元模拟证明，具有高度暴露的活性位点和大界面接触面积的中空立方结构进一步促进了OER，从而实现高电流密度。 V _o -Co ₃ O ₄ HNCs 在 PEM 电解槽中的应用稳定在 1 A cm ⁻² 能耗达到 48.8 kW h kg ⁻¹ H ₂ 预计成本约为 0.976 美元 kg ⁻¹ H ₂ （能源部的目标：2 美元 kg <到 2026 年，H ₂ 的 b16>），表明使用地球丰富的材料进行 PEM 水电解的前景。