Effect of Nitrogen Doping and Oxygen Vacancy on the Oxygen Reduction Reaction on the Tetragonal Zirconia(101) Surface
Effect of Nitrogen Doping and Oxygen Vacancy on the Oxygen Reduction Reaction on the Tetragonal Zirconia(101) Surface
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DOI：
10.1021/acs.jpcc.2c04132
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发表时间：
2022-09
期刊：
影响因子：
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通讯作者：
Shibghatullah Muhammady;Jun Haruyama;S. Kasamatsu;O. Sugino
中科院分区：
文献类型：
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作者：
Shibghatullah Muhammady;Jun Haruyama;S. Kasamatsu;O. Sugino
在这项研究中，我们研究了缺陷在促进氧化锆基阴极的氧还原反应（ORR）中的作用，这是出于对质子交换膜燃料电池稳定和活性电催化剂的需要。用引入氧空位和氮掺杂的四元ZrO2（101）平板模拟了缺陷催化剂，并从第一性原理计算了ORR中间体的结构.作为典型的氧化物，不同的吸附结构与略有不同的能量。因此，我们获得了ORR的自由能曲线，并确定了速率决定步骤或OH* 去除的能垒与原始表面的能垒相当（或仅略低于原始表面的能垒），表明缺陷在增强ORR活性方面仅起次要作用。ORR电流的测量增强可以归因于增强的载流子供应，这可以归因于间隙状态的形成或电势分布的变化，或者归因于迄今为止被忽视的其他因素。第一性原理研究的结果为实验人员开发最佳阴极材料提供了重要的见解。
In this study, we investigated the role of defects in promoting the oxygen reduction reaction (ORR) of a zirconia-based cathode, which is motivated by the need for a stable and active electrocatalyst for proton exchange membrane fuel cells. A defective catalyst was modeled by a tetragonal ZrO2(101) slab introduced with oxygen vacancies and nitrogen dopants, and the structure of the ORR intermediates was exhaustively computed from first principles. As is typical of oxides, various adsorption structures with slightly different energies were obtained. Therefore, we obtained the free energy profile for the ORR and established that the energy barrier of the rate-determining step, or the removal of OH*, is comparable to (or only slightly lower than) that of the pristine surfaces, indicating that defects play only a minor role in enhancing the ORR activity. The measured enhancement in the ORR current could be ascribed to the enhanced carrier supply, which may be attributed to the formation of a gap state or change in the potential profile, or to other factors so far overlooked. The results of the first-principles study provide a significant insight for experimentalists to develop optimal cathode materials.