Tanwar Deepika, Jain Priya, Ahluwalia Deepali, Sudheendranath Athul, Thomas Sajesh P, Ingole Pravin P, Kumar Umesh
Catalysis and Bioinorganic Research Lab, Department of Chemistry, Deshbandhu College, University of Delhi New Delhi-110019 India
Department of Chemistry, University of Delhi New Delhi-110007 India.
RSC Adv. 2023 Aug 15;13(35):24450-24459. doi: 10.1039/d3ra04709a. eCollection 2023 Aug 11.
Developing cost-effective electrocatalysts using earth-abundant metal as an alternative to expensive precious metal catalyst remains a key challenge for researchers. Several strategies are being researched/tested for making low-cost transition metal complexes with controlled electron-density and coordination flexibility around the metal center to enhance their catalytic activity. Herein, we report a novel lutidine coordinated cobalt(ii) acetate complex [(3,5-lutidine)Co(OAc)(HO)] (1) as a promising electrocatalyst for oxygen evolution reaction (OER). Complex 1 was characterized by FT-IR, elemental analysis, and single crystal X-ray diffraction data. The structure optimization of complex 1 was also done using DFT calculation and the obtained geometrical parameters were found to be in good agreement with the parameters obtained from the solid state structure obtained through single crystal X-ray diffraction data. Further, the molecular electrostatic potential (MEP) maps analysis of complex 1 observed electron rich centers that were found to be in agreement with the solid-state structure. It was understood that the coordination of lutidine as a Lewis base and acetate moiety as a flexible ligand will provide more coordination flexibility around the metal center to facilitate the catalytic reaction. Further, the electron rich centers around metal center will also support the enhancement of their catalytic activity. Complex 1 shows impressive OER activity, even better than the state-of-the-art IrO catalyst, in terms of turnover frequency (TOF: 0.05) and onset potential (1.50 V RHE). The TOF for complex 1 is two and half times higher, while the onset potential is 20 mV lower, than the benchmark IrO catalyst studied under identical conditions.
使用储量丰富的金属开发具有成本效益的电催化剂以替代昂贵的贵金属催化剂，仍然是研究人员面临的关键挑战。目前正在研究/测试几种策略，以制备具有可控电子密度和金属中心周围配位灵活性的低成本过渡金属配合物，以提高其催化活性。在此，我们报道了一种新型的2,6-二甲基吡啶配位的醋酸钴（II）配合物[(3,5-二甲基吡啶)Co(OAc)(HO)]（1），它是一种有前景的析氧反应（OER）电催化剂。配合物1通过傅里叶变换红外光谱、元素分析和单晶X射线衍射数据进行了表征。还使用密度泛函理论（DFT）计算对配合物1进行了结构优化，发现得到的几何参数与通过单晶X射线衍射数据获得的固态结构参数吻合良好。此外，对配合物1的分子静电势（MEP）图分析观察到富电子中心，这与固态结构一致。据了解，2,6-二甲基吡啶作为路易斯碱和醋酸根部分作为柔性配体的配位将在金属中心周围提供更大的配位灵活性，以促进催化反应。此外，金属中心周围的富电子中心也将支持其催化活性的增强。配合物1在周转频率（TOF：0.05）和起始电位（1.50 V vs. RHE）方面表现出令人印象深刻的OER活性，甚至优于目前最先进的IrO催化剂。在相同条件下研究时，配合物1的TOF比基准IrO催化剂高两倍半，而起始电位低20 mV。
