The electrocatalytic nitrate reduction reaction (NO₃⁻RR) presents a promising pathway for achieving both ammonia (NH₃) electrosynthesis and water pollutant removal simultaneously. Among various electrocatalysts explored, 2D materials have emerged as promising candidates due to their ability to regulate electronic states and active sites through doping. However, the impact of doping effects in 2D materials on the mechanism of NO₃⁻RR remains relatively unexplored. Here, Ni-doped MoS₂ (Ni-MoS₂) nanosheets are investigated as a model system, demonstrating enhanced NO₃⁻RR performance compared to undoped counterparts. By controlling the doping concentration, the Ni-MoS₂ nanosheets achieve a remarkable faradic efficiency (FE) of 92.3% for NH₃ at −0.3 V_RHE with excellent stability. The mechanistic studies reveal that the elevation of the NO₃⁻RR performances originates from the generation of more active hydrogen and the acceleration of the reaction from nitrite (NO₂⁻) to NH₃ facilitated by Ni doping. Combining the experimental observations and theoretical calculations it is revealed that the appropriate Ni doping level in MoS₂ can enhance *NO₃ adsorption strength, thereby facilitating subsequent electrocatalytic steps. Together with the demonstration of Zn−NO₃⁻ and Zn−NO₂⁻ battery devices, the work provides new insights into the design and regulation of the active sites in 2D material catalysts for efficient NO₃⁻RR.

中文翻译：

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在原子薄的二硫化钼中设计镍掺杂剂，用于高效将硝酸盐还原为氨


电催化硝酸盐还原反应 （NO₃⁻RR） 为同时实现氨 （NH₃） 电合成和水污染物去除提供了一种有前途的途径。在探索的各种电催化剂中，二维材料因其能够通过掺杂调节电子态和活性位点而成为有前途的候选材料。然而，二维材料中的掺杂效应对 NO ^3-RR 机制的影响仍相对未得到探索。在这里，Ni 掺杂的 MoS₂ （Ni-MoS₂） 纳米片作为模型系统进行了研究，与未掺杂的纳米片相比，证明了增强的 NO₃⁻RR 性能。通过控制掺杂浓度，Ni-MoS₂ 纳米片在 −0.3 V_RHE 下对 NH₃ 实现了 92.3% 的显着法拉第效率 （FE），具有出色的稳定性。机理研究表明，NO₃⁻RR 性能的升高源于更活性氢的产生以及 Ni 掺杂促进亚硝酸盐 （NO₂⁻） 到 NH₃ 的反应加速。结合实验观察和理论计算，揭示了 MoS₂ 中适当的 Ni 掺杂水平可以提高 *NO₃ 的吸附强度，从而促进后续的电催化步骤。结合 Zn-NO₃^-和 Zn-NO₂^-电池器件的演示，这项工作为高效 NO ^3-RR 的 2D 材料催化剂中活性位点的设计和调节提供了新的见解。