In situ Electropolymerized 3D Microporous Cobalt‐Porphyrin Nanofilm for Highly Effective Molecular Electrocatalytic Reduction of Carbon Dioxide

Abstract

Electrocatalytic CO2 reduction reaction (CO2RR) 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 CoN4 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 CoN4 sites. The new electrocatalyst shortens the electron transfer pathway, accelerates the redox kinetics of CoN4 sites, and improves the durability of the electrocatalytic CO2RR. From the intrinsic redox behavior of CoN4 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 (FECO) over 92% at an overpotential of 160 mV. At a higher overpotential of 620 mV, the working current density can reach 310 mA cm−2 with a high FECO of 98.6%, representing the best performance for electrodeposited molecular porphyrin electrocatalysts.

Single‐atom materials: The application in energy conversion

“…Besides, the research in SAMs should pay more attention to the molecule catalysts due to the total uniform active sites. [90][91][92][93][94][95] With the advanced techniques and theory, the day of fully designing the SAMs will be soon. As a result, the renovation of SAMs will be much faster and it will bring the application of SAMs to the new epoch.…”

A molecular view of single-atom catalysis toward carbon dioxide conversion

“…103,107,266–270 Rather than their role in the photochemical catalytic reactions for light harvesting and charge dynamics as mentioned in Section 3.1, 226,242 the exploitation of their rigid, robust and multifunctional porous framework is more universal and widely realized in non-photochemical CO 2 transformation processes. 405 By using polystyrene spheres (PS) as a hard template during the synthesis of iron-doped ZIF-8, highly ordered hierarchical porous single-atom Fe catalysts are fabricated as an excellent platform to investigate the pore size effect on electrochemical CO 2 reduction in detail (Fig. 49).…”

Electrocatalytic reduction of CO2 to CO by Fe(iii) carbazole–porphyrins in homogeneous molecular systems

“…In commercial flow cells, the working current density reaches 310 mA cm −2 with a high FE CO of 98.6% at a higher overpotential of 620 mV. 8 However, their catalytic active sites are only located on the surface of the catalytic materials, which restrict the full utilization of the catalyst. 9,10 On the other hand, homogeneous metal complexes are essential systems for studying CO 2 RR mechanisms at a molecular level, offering superior selectivity and exceptional activity.…”