Zhang Wuyi, Mehmood Asad, Ali Ghulam, Liu Hui, Chai Liyuan, Wu Jun, Liu Min
School of Metallurgy and Environment, Central South University, Changsha, 410083, China.
Division 3.6 - Electrochemical Energy Materials, Bundesanstalt für Materialforschung und -prüfung (BAM), 12203, Berlin, Germany.
Angew Chem Int Ed Engl. 2025 Mar 24;64(13):e202424552. doi: 10.1002/anie.202424552. Epub 2025 Jan 27.
Unsaturated Ni single-atom catalysts (SACs), Ni-N (x=1,2,3), have been investigated to break the conventional Ni-N structural limitation and provide more unoccupied 3d orbitals for CO reduction reaction (CORR) intermediates adsorption, but their intrinsically low structural stability has seriously hindered their applications. Here, we developed a strategy by integrating Ni nanoclusters to stabilize unsaturated Ni-N atomic sites for efficient CO electroreduction to CO at industrial-level current. Density Functional Theory (DFT) calculations revealed that the incorporation of Ni nanocluster effectively stabilizes the unsaturated Ni-N atomic sites and modulates their electronic structure to enhance the adsorption of the key intermediate *COOH during CORR. Guided by these insights, we prepared an optimal composite catalyst, Ni@Ni-N, which features a NiN nanocluster surrounded by six Ni-N single atoms sites, through low-temperature pyrolysis. The morphology and coordinative structure of Ni@Ni-N were confirmed by an aberration-corrected transmission electron microscope (AC-TEM) and X-ray absorption spectroscopy (XAS). As a result, Ni@Ni-N demonstrated a remarkably high CO Faradaic efficiency (FE) of 99.7 % and a turnover frequency (TOF) of 83984.2 h at 500 mA cm under -1.15 V, much better than those of Ni-N with a lower FE of 86 % at 100 mA cm and a TOF of 39309.9 hunder identical potential. XAS analyses of Ni@Ni-N before and after long-term CORR testing confirmed the excellent stability of its coordinative environment. This work highlights a generalizable approach for stabilizing unsaturated single-atom catalysts, paving the way for their application in high-performance CORR.
不饱和镍单原子催化剂（SACs），即Ni-N（x=1,2,3），已被研究用于打破传统的Ni-N结构限制，并为CO还原反应（CORR）中间体吸附提供更多未占据的3d轨道，但其固有的低结构稳定性严重阻碍了它们的应用。在此，我们开发了一种通过整合镍纳米团簇来稳定不饱和Ni-N原子位点的策略，以在工业级电流下将CO高效电还原为CO。密度泛函理论（DFT）计算表明，镍纳米团簇的引入有效地稳定了不饱和Ni-N原子位点，并调节了它们的电子结构，以增强CORR过程中关键中间体*COOH的吸附。基于这些见解，我们通过低温热解制备了一种最佳复合催化剂Ni@Ni-N，其特征是由六个Ni-N单原子位点包围的NiN纳米团簇。通过像差校正透射电子显微镜（AC-TEM）和X射线吸收光谱（XAS）确认了Ni@Ni-N的形貌和配位结构。结果，Ni@Ni-N在-1.15 V下500 mA cm时表现出高达99.7%的CO法拉第效率（FE）和83984.2 h的周转频率（TOF），远优于Ni-N，后者在相同电位下100 mA cm时FE为86%，TOF为39309.9 h。长期CORR测试前后Ni@Ni-N的XAS分析证实了其配位环境的优异稳定性。这项工作突出了一种稳定不饱和单原子催化剂的通用方法，为其在高性能CORR中的应用铺平了道路。
