Wang Chao, Chen Yuzhuo, Su Daijian, Man Wai-Lun, Lau Kai-Chung, Han Lianhuan, Zhao Liubin, Zhan Dongping, Zhu Xunjin
State Key Laboratory of Physical Chemistry of Solid Surfaces, Fujian Science & Technology Innovation Laboratory for Energy Materials of China, Engineering Research Center of Electrochemical Technologies of Ministry of Education, Department of Chemistry, College of Chemistry and Chemical Engineering, Department of Mechanical and Electrical Engineering, School of Aerospace Engineering, Xiamen University, Xiamen, 361005, China.
Department of Chemistry and State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
Adv Mater. 2023 Sep;35(38):e2303179. doi: 10.1002/adma.202303179. Epub 2023 Jul 26.
Electrocatalytic CO reduction reaction (CO RR) based on molecular catalysts, for example, cobalt porphyrin, is promising to enhance the carbon cycle and mitigate current climate crisis. However, the electrocatalytic performance and accurate evaluations remain problems because of either the low loading amount or the low utilization rate of the electroactive CoN sites. Herein a monomer is synthesized, cobalt(II)-5,10,15,20-tetrakis(3,5-di(thiophen-2-yl)phenyl)porphyrin (CoP), electropolymerized onto carbon nanotubes (CNTs) networks, affording a molecular electrocatalyst of 3D microporous nanofilm (EP-CoP, 2-3 nm thickness) with highly dispersed CoN sites. The new electrocatalyst shortens the electron transfer pathway, accelerates the redox kinetics of CoN sites, and improves the durability of the electrocatalytic CO RR. From the intrinsic redox behavior of CoN sites, the effective utilization rate is obtained as 13.1%, much higher than that of the monomer assembled electrode (5.8%), and the durability is also promoted dramatically (>40 h) in H-type cells. In commercial flow cells, EP-CoP can achieve a faradic efficiency for CO (FE ) over 92% at an overpotential of 160 mV. At a higher overpotential of 620 mV, the working current density can reach 310 mA cm with a high FE of 98.6%, representing the best performance for electrodeposited molecular porphyrin electrocatalysts.
基于分子催化剂（例如钴卟啉）的电催化CO还原反应（CO RR），有望增强碳循环并缓解当前的气候危机。然而，由于电活性CoN位点的负载量低或利用率低，电催化性能和准确评估仍然是问题。在此合成了一种单体，即钴（II）-5,10,15,20-四（3,5-二（噻吩-2-基）苯基）卟啉（CoP），将其电聚合到碳纳米管（CNT）网络上，得到一种具有高度分散的CoN位点的3D微孔纳米膜分子电催化剂（EP-CoP，厚度为2-3nm）。这种新型电催化剂缩短了电子转移途径，加速了CoN位点的氧化还原动力学，并提高了电催化CO RR的耐久性。根据CoN位点的固有氧化还原行为，有效利用率为13.1%，远高于单体组装电极（5.8%），并且在H型电池中的耐久性也显著提高（>40小时）。在商业流通池中，EP-CoP在160mV的过电位下可以实现超过92%的CO法拉第效率（FE）。在620mV的更高过电位下，工作电流密度可以达到310mA cm，FE高达98.6%，代表了电沉积分子卟啉电催化剂的最佳性能。
