Yang Zihao, Fang Cong, Guo Xiuling, Sun Xiaoyan, Yang Yong
Key Laboratory of Photoelectric Conversion and Utilization of Solar Energy, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Small. 2025 Jan;21(1):e2408111. doi: 10.1002/smll.202408111. Epub 2024 Oct 24.
Electrochemical reduction of N (NRR) offers a sustainable approach for ammonia (NH) synthesis, serving as a complementary to the traditional emission- and energy-intensive Haber-Bosch process. However, it faces challenges in N activation and competing with pronounced hydrogen evolution reaction (HER). Herein an efficient electrocatalyst comprised of ultrafine Ru nanoclusters (NCs) confined by a hydrophobic molecular layer is developed on the surface of 2D TiCT for NRR. These experimental and theoretical calculation results demonstrate that 1) ultrafine Ru NCs dispersed on the TiCT surface form paired active sites for N chemisorption in a unique tilted configuration with low-energy activation 2) the hydrophobic molecular layer modulates the local microenvironment surrounding catalytically active sites, enabling efficient N accumulation while repelling HO diffusion to the active sites on the TiCT surface, thereby leading to an increased N concentration and suppressed HER. As a result, an exceptionally high NH yield rate of 33.5 µg h mgcat and Faradaic efficiency of 65.3% are obtained at -0.25 V versus reversible hydrogen electrode (RHE) in 0.1 m NaSO, outperforming those previously reported TiCT-derived electrocatalysts. This work provides a valuable strategy for the rational design of advanced electrocatalysts by manipulating active sites and local microenvironments for efficient electrocatalysis.
氮的电化学还原（NRR）为氨（NH₃）合成提供了一种可持续的方法，可作为传统的高排放和高能耗哈伯-博施法的补充。然而，它在氮活化以及与明显的析氢反应（HER）竞争方面面临挑战。在此，在二维TiCT表面开发了一种由疏水分子层限制的超细钌纳米团簇（NCs）组成的高效电催化剂用于NRR。这些实验和理论计算结果表明：1）分散在TiCT表面的超细钌纳米团簇形成了成对的活性位点，以独特的倾斜构型进行氮的化学吸附，活化能较低；2）疏水分子层调节了催化活性位点周围的局部微环境，能够有效地积累氮，同时排斥水分子扩散到TiCT表面的活性位点，从而导致氮浓度增加并抑制HER。结果，在0.1 m Na₂SO₄中，相对于可逆氢电极（RHE），在-0.25 V时获得了33.5 μg h⁻¹ mgcat⁻¹的超高氨产率和65.3%的法拉第效率，优于先前报道的源自TiCT的电催化剂。这项工作通过操纵活性位点和局部微环境以实现高效电催化，为先进电催化剂的合理设计提供了有价值的策略。
