The electrocatalytic synthesis of urea by coupling of nitrate ions as a wastewater pollutant with CO₂ is a sustainable pathway. However, efficient electrosynthesis of urea across a broad range of nitrate concentrations has not been reported. Here, a series of Ru-doped Cu_xBi/CNT multisite catalysts for urea electrosynthesis are designed to benefit from triple synergistic modulation and exhibit excellent performance. The composition and ratio optimised Ru–Cu₉Bi/CNT catalyst achieves urea yields greater than 40.0 mmol h⁻¹ g⁻¹ over a wide range of nitrate concentrations (10–1000 mM) at −0.4 V vs. RHE. Notably, the highest FE value of 75.6% to date was achieved in 1 M nitrate solution. Comprehensive analysises show that the Cu and Bi sites activate CO₂ and NO₃⁻, respectively. In addition, doped Ru promotes water dissociation to form *H. In the key step of electrocatalytic urea synthesis, the strong adsorption of *H by doped Ru inhibits the hydrogen evolution reaction (HER). The acceleration of NO₃⁻ reduction by Bi synergises with the modulation of *H adsorption energy by Ru to improve the coverage of the key intermediate *NHO at different NO₃⁻ concentrations, ensuring the subsequent electrosynthesis of urea.

中文翻译：

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通过提高关键中间体在广泛硝酸盐浓度范围内的覆盖率，实现高效的尿素电合成


通过废水污染物硝酸根离子与 CO ₂ 的耦合电催化合成尿素是一种可持续的途径。然而，在广泛的硝酸盐浓度范围内有效电合成尿素尚未见报道。在此，设计了一系列用于尿素电合成的Ru掺杂Cu _x Bi/CNT多位点催化剂，受益于三重协同调节并表现出优异的性能。成分和比例优化的 Ru-Cu ₉ Bi/CNT 催化剂可在较宽的硝酸盐浓度范围内实现大于 40.0 mmol h ⁻¹ g ⁻¹ 的尿素产量（ 10–1000 mM)，相对于 RHE，-0.4 V。值得注意的是，迄今为止 75.6% 的最高 FE 值是在 1 M 硝酸盐溶液中实现的。综合分析表明，Cu位点和Bi位点分别激活CO ₂ 和NO ₃ ⁻ 。此外，掺杂的Ru促进水解离形成*H。在电催化尿素合成的关键步骤中，掺杂Ru对*H的强烈吸附抑制了析氢反应（HER）。 Bi加速NO ₃ ⁻ 还原与Ru调节*H吸附能协同作用，提高了关键中间体*NHO在不同NO ₃ 浓度，保证后续尿素的电合成。