Molecularly Dispersed Cobalt Phthalocyanine Mediates Selective and Durable CO₂ Reduction in a Membrane Flow Cell

Abstract

High‐rate electrochemical CO2‐to‐CO conversion provides a favorable strategy for carbon neutrality. Molecular catalysts, especially those with isolated metal active centers, are known to be the efficient CO2‐to‐CO electrocatalysts due to their high selectivity and outstanding instinct activity; however, the controllable scale‐up synthesis and durable utilization at industrial current densities still remain a challenge. Here, it is developed a molecularly dispersed cobalt phthalocyanine loaded on carbon nanotube for high‐current long‐term CO2‐to‐CO electrolysis. The resultant catalyst exhibits a high CO selectivity with a maximum Faradaic efficiency of 97% and performs a current density of −200 mA cm−2 in a flow cell with a TOF of 83.9 s−1, which is among the best of CO‐selective electrocatalysts. With a series of impregnation loading experiments, the process of molecular‐dispersion or aggregation is investigated. In addition, the application of selective and durable electrolysis at a current of 0.25 A is realized up to 38.5 h in a scale‐up MEA configuration. Subsequent characterization shows robust durability closely related to the dispersion of CoPc. This study provides a triumph to catalyze commercial‐scale CO production using molecularly dispersed phthalocyanine electrocatalysts.

Ultrathin Cobalt Phthalocyanine@Graphene Oxide Layer-Modified Separator for Stable Lithium–Sulfur Batteries

“…Figure a shows the X-ray diffraction (XRD) patterns of CoPc and CoPc@GO. CoPc@GO displays obvious diffraction peaks at 7.0, 9.2, 10.5, 18.2, 18.6, 23.1, 23.9, and 26.3°, matching well with β-phase CoPc (JCPDS NO.14-0948) . The Raman spectrum of GO displays a broad D band peak at ∼1345 cm –1 and a G band at ∼1598 cm –1 (Figure b).…”

“…CoPc@GO displays obvious diffraction peaks at 7.0, 9.2, 10.5, 18.2, 18.6, 23.1, 23.9, and 26.3°, matching well with β-phase CoPc (JCPDS NO.14-0948). 37 The Raman spectrum of GO displays a broad D band peak at ∼1345 cm −1 and a G band at ∼1598 cm −1 (Figure 2b). Raman spectra show that the obvious peaks of pure CoPc are relatively strong, and some characteristic peaks are slightly reflected for the CoPc@GO composite.…”

Development of catalysts and electrolyzers toward industrial-scale CO2electroreduction

“…However, molecular catalysts tend to suffer from poor electroconductivity and stability issues. Immobilizing molecular catalysts on carbonaceous supports such as carbon nanotubes (CNTs), 37 carbon black (CB), 38 and carbon paper (CP) 39 can be an effective method to improve the current density and stability. The supports with high surface area, high conductivity, and catalytic inertness are conducive, as otherwise, they could interfere with the CO 2 RR.…”

“…The supports with high surface area, high conductivity, and catalytic inertness are conducive, as otherwise, they could interfere with the CO 2 RR. [40][41][42] Zhao et al 37 dispersed CoPc on CNTs via p-p stacking interactions, achieving an FE CO of 97% at 200 mA cm À2 . In addition, the molecularly dispersed CoPc on CNTs presented higher catalytic activity and stability than the aggregated one.…”

Enzyme‐Inspired Microenvironment Engineering of a Single‐Molecular Heterojunction for Promoting Concerted Electrochemical CO2 Reduction

“…[1][2][3] Crucially, how to design and construct efficient electrocatalysts under industrial-level operation has important strategic significance. [4,5] Significant efforts in this fascinating field have been devoted to exploring electrocatalytic materials with a high performance for CO 2 conversion, such as noble metals, [6][7][8][9][10] carbon-based singleatoms, [11][12][13][14] metal-organic frameworks/ covalent organic frameworks (MOFs/ COFs), [15][16][17][18][19][20] dispersed molecules, [21][22][23][24][25][26][27] etc. Among these electrocatalytic materials, particularly the π-conjugated metallomacrocyclic molecules (e.g., phthalocyanines and porphyrins) heterogenized at the single-molecular level, namely single-molecular heterojunction (SMH) electrocatalysts, offer an ideal platform for eCO 2 RR and reaction mechanism studies due to the definite coordination structures of metal centers, relatively uncomplicated synthetic procedures and flexible design assembling.…”