The design and development of strategies and catalysts are essential for sustainable energy production, particularly for the hydrogen evolution reaction (HER). Precious Pt/C catalyst is known to demonstrate high efficiency in the electrochemical HER and suffers from commercialization issues. Therefore, precious-metal-free and organic-based catalysts are of importance for a future perspective. In this work, cobalt tetra[4-[2-(1H-benzimidazol-2-yl)phenoxy]]phthalocyanine (CoTBImPc) is synthesized for the first time and characterized by physicochemical and electrochemical techniques. ¹H NMR and mass spectral data reveal the successful formation of the ligand and complex, whereas the thermogravimetry (TG) study confirms the thermal stability of the complex up to 400 °C. The electroactivity of CoTBImPc is compared with the hybrid composite of a carbon nanotube (CNT-CoTBImPc) and benchmark Pt/C catalyst for the HER. Linear sweep voltammetry (LSV) shows that an onset potential for the HER for CoTBImPc-CNT/GCE is shifted to a higher potential than that of CoTBImPc/GCE, suggesting that the HER is more feasible at the surface of CoTBImPc-CNT. Higher activity for CoTBImPc-CNT/GCE in comparison with that of CoTBImPc/GCE in 0.5 M H₂SO₄ (pH = 0.3) may be ascribed to the enhanced conductivity, a greater number of active sites, and a larger surface area. The hybrid composite yields a current density of −10 mA·cm^–2 and demonstrates HER activity at a lower overpotential (63 mV). The benchmark Pt/C catalyst and the as-synthesized pristine phthalocyanine molecule exhibit the HER at overpotentials of 3 and 160 mV, respectively, at a current density of −10 mA·cm^–2. A lower Tafel slope value of 43.2 mV·dec^–1 and a higher double-layer capacitance value of 44 mF·cm^–2 confirm that the hybrid composite is one of the superior catalyst candidates for the HER compared to the bare glassy carbon electrode (GCE) and pristine metal phthalocyanine. Further, CoTBImPc-CNT/GCE also exhibits an excellent stability during the HER.

中文翻译：

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仿生无贵金属 N4 大环化合物作为析氢反应的电催化剂

策略和催化剂的设计和开发对于可持续能源生产至关重要，特别是对于析氢反应 (HER)。众所周知，贵重 Pt/C 催化剂在电化学 HER 中表现出高效率，但存在商业化问题。因此，无贵金属和有机基催化剂对于未来的前景非常重要。在这项工作中，首次合成了四[4-[2-(1 H-苯并咪唑-2-基)苯氧基]]酞菁钴( CoTBImPc )，并通过物理化学和电化学技术对其进行了表征。¹H NMR 和质谱数据揭示了配体和配合物的成功形成，而热重 (TG) 研究证实了配合物的热稳定性高达 400 °C。将CoTBImPc的电活性与碳纳米管 ( CNT-CoTBImPc ) 和用于 HER 的基准 Pt/C 催化剂的混合复合材料进行比较。线性扫描伏安法 (LSV) 显示CoTBImPc -CNT/GCE的 HER 起始电位转移到比CoTBImPc /GCE更高的电位，表明 HER 在CoTBImPc -CNT表面更可行。在 0.5 MH ₂ SO 中，与CoTBImPc /GCE相比，CoTBImPc-CNT/GCE 的活性更高₄ (pH = 0.3) 可能归因于增强的导电性、更多的活性位点和更大的表面积。混合复合材料产生 -10 mA·cm ^–2的电流密度，并在较低的过电位 (63 mV) 下显示出 HER 活性。基准 Pt/C 催化剂和合成的原始酞菁分子在 -10 mA·cm ^–2的电流密度下分别在 3 和 160 mV 的过电位下表现出 HER 。较低的 Tafel 斜率值 43.2 mV·dec ^–1和较高的双层电容值 44 mF·cm ^–2证实与裸玻碳电极 (GCE) 和原始金属酞菁相比，混合复合材料是 HER 的优良催化剂候选者之一。此外，CoTBImPc-CNT/GCE 在 HER 过程中也表现出优异的稳定性。