Electrochemical nitrogen reduction reaction (NRR) driven by a renewable energy source offers a sustainable and environmentally benign route to produce ammonia (NH₃), but it is highly dependent on efficient and specific catalysts to reduce the high reaction barrier and improve the selectivity. Defect engineering is extensively used to regulate the surface properties of materials to improve their catalytic performance. Herein we synthesized SnO₂ with different oxygen vacancy concentrations by a controllable electrochemical method for electrocatalytic nitrogen (N₂) fixation. The prepared SnO₂ was used as an electrocatalyst and exhibited excellent NRR performance with an optimal NH₃ yield rate of 25.27 μg h⁻¹ mg_cat.⁻¹ and faradaic efficiency of 11.48% at −0.6 V (vs. the reversible hydrogen electrode) in 0.1 M Na₂SO₄. Oxygen vacancies provide more active sites and greater electron transfer ability on the catalyst surface to facilitate N₂ adsorption and activation. The electrocatalytic NRR performance of SnO₂ was enhanced with the increase in oxygen vacancy concentration. The density functional theory calculations indicate that the oxygen vacancies in SnO₂ promote the electrocatalytic NRR performance by increasing the number of valence electrons of Sn and decreasing the energy barrier of the potential-determining step, thus promoting the activation of the N–N bond to further achieve efficient N₂ fixation.

中文翻译：

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电化学合成的具有可调氧空位的 SnO2 用于高效电催化固氮

由可再生能源驱动的电化学氮还原反应 (NRR) 提供了一条可持续且环境友好的生产氨 (NH ₃ ) 的途径，但它高度依赖于高效和特定的催化剂来降低高反应势垒并提高选择性。缺陷工程被广泛用于调节材料的表面性质以提高其催化性能。在此，我们通过用于电催化固氮 (N ₂ )的可控电化学方法合成了具有不同氧空位浓度的SnO ₂。制备的 SnO ₂用作电催化剂并表现出优异的 NRR 性能，最佳 NH ₃产率为 25.27 μg·h⁻¹毫克_猫。^-1和 11.48% 的法拉第效率在 -0.6 V（相对于可逆氢电极）在 0.1 M Na ₂ SO _{4 中}。氧空位在催化剂表面提供更多的活性位点和更大的电子转移能力，以促进N ₂吸附和活化。SnO ₂的电催化NRR性能随着氧空位浓度的增加而增强。密度泛函理论计算表明，SnO ₂中的氧空位通过增加Sn的价电子数和降低电位决定步骤的能垒来提高电催化NRR性能，从而促进N-N键的活化以进一步实现有效的N ₂固定。