Improving the lifetime of hybrid CoPc@MWCNT catalysts for selective electrochemical CO2-to-CO conversion

• DOI: 10.1016/j.jcat.2022.02.001
• Publication Date: 2022-02-07T17:00:29Z
• Authors: Changzhe Sun; Yuhui Hou; Nicola Lüdi; Huifang Hu; María de Jesús Gá...; Mike Liechti; Ying Kong; Menglong Liu; Rolf Erni; Alexander V. Rudnev; Peter Broekmann
• Keywords: Degradation; Hybrid material; Selective catalytic reduction

Molecular hybrid catalysts, such as cobalt(II) phthalocyanine (CoPc) complexes anchored to multi-walled carbon nanotubes (MWCNTs), provide selective CO2 conversion toward CO with high current densities, exceeding 0.1 A cm−2 in microfluidic or zero-gap (membrane) electrolyzers. However, the practicality of electroreduction is essentially determined by catalyst stability against mechanical and (electro)chemical degradation. Here, we report a new mechanism for observable degradation [email protected] catalyst. Even at moderate reduction potentials, demetalation CoPc induced iron (Fe) species, which can contaminate commercially available MWCNTs solvents used preparation. Minimization Fe contamination leads substantial improvement lifetime, faradaic efficiency formation decreasing from 98% 96% (by only 2%) after 95 h electrolysis. Thus, careful purification materials required maintain initial levels performance during long-term operation.