Revealing the structure-activity relationship of two Cu-porphyrin-based metal-organic frameworks for the electrochemical CO-to-HCOOH transformation

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 49; no. 42; pp. 14995 - 151
• Main Authors: Liu, Meng-Jie, Cao, Si-Min, Feng, Bao-Qi, Dong, Bao-Xia, Ding, Yan-Xia, Zheng, Qiu-Hui, Teng, Yun-Lei, Li, Zong-Wei, Liu, Wen-Long, Feng, Li-Gang
• Format: Journal Article
• Language: English
• Published: 03.11.2020
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d0dt02683b

The eCO 2 RR activity is correlated to the internal structural character of the catalyst. We employed two types of structural models of porphyrin-based MOFs of PCN-222(Cu) and PCN-224(Cu) into heterogeneous catalysis to illustrate the effect of structural factors on the eCO 2 RR performance. The composite catalyst PCN-222(Cu)/C displays better activity and selectivity ( η = 450 mV, FE HCOOH = 44.3%, j = 3.2 mA cm −2 ) than PCN-224(Cu)/C ( η = 450 mV, FE HCOOH = 34.1%, j = 2.4 mA cm −2 ) for the CO 2 reduction to HCOOH in the range of −0.7-−0.9 V ( vs . RHE) due to its higher BET surface area, CO 2 uptake, and a larger pore diameter. It is interesting that PCN-224(Cu)/C displays better performance in the range of −0.4-−0.6 V ( vs . RHE) due to its greater heat of adsorption, Q st and a higher affinity for CO 2 molecule, which could promote the capture of CO 2 onto the exposed active sites. As a result, PCN-224(Cu)/C exhibits better stability for the long-term electrolysis. Two types of structural models of PCN-222(Cu) and PCN-224(Cu) were chosen for clarifying the effect of structural factors on the eCO 2 RR performance of them.