Proton/Electron Donors Enhancing Electrocatalytic Activity of Supported Conjugated Microporous Polymers for CO₂Reduction

Abstract

Metal phthalocyanines (MePc) hold great promise in electrochemical reduction of CO 2 to value-added chemicals, whereas the catalytic activity of MePc-containing polymers often suffers from a limited molecular modulation strategy. Herein, we synthesize an ultrathin conjugated microporous polymer sheath around carbon nanotubes by an ionothermal copolymerization of CoPc and H 2 Pc via the Scholl reaction. Given the H 2 Pc-mediated regulation in the synthesis, Co II metal is well preserved in the form of single atoms on the polymer sheath of the carbon nanotubes. With the synergistic effect of H 2 Pc moieties as proton/electron donors, the composites can selectively reduce CO 2 to CO with a high Faradaic efficiency (max. 97 % at À 0.9 V) in broad potential windows, exceptional turnover frequency (97 592 h À 1 at À 0.65 V) and large current density (> 200 mA cm À 2 ). It is thus desirable to develop a family of heterogeneous polymerized MePc with molecularly regulating electrocatalytic activity.

Multicomponent catalyst design for CO2/N2/NOxelectroreduction

“…41 Guo and coworkers recently reported the phthalocyanines polymerized through solid ion thermal utilizing Scholl reaction (Figure 5A) with carbon nanotubes as the substrates, which could provide both CoN 4 sites and H 2 Pc sites for CO 2 RR. 42 As is shown in Figure 5B, in the phthalocyanine catalysts, CoN 4 could serve as the active sites to interact with CO 2 molecules while H 2 Pc sites could boost CO 2 RR as the donors of protons and electrons. As a result, the performance of phthalocyanines could reach the FE of 97% with a large current density of >200 mA cm -2 .…”

Advances in Biomimetic Photoelectrocatalytic Reduction of Carbon Dioxide

“…For example, the proton donor H 2 Pc can facilitate the selective CO 2 reduction to CO on a conjugated composite microporous CoPc/H 2 Pc polymer catalyst (Figure 8d ). [ 119 ] The measurement of kinetic isotope effect (KIE) indicated that the rate‐determining step was the proton transfer process, and the addition of the proton donor, H 2 Pc, decreased the KIE value from 4.0 to 1.77, signifying accelerated proton transfer. The proton donor H 2 Pc lowered the energy barrier of the reduction of *CO 2 to the *COOH intermediate and the further reduction of *COOH to *CO.…”

Bifunctional Nb-N-C atomic catalyst for aqueous Zn-air battery driving CO2 electrolysis

“…Many pioneering efforts have also demonstrated that atomically dispersed active sites anchored onto NC substrates can effectively enhance ORR performances, indicating a preferable application of NC substrates [38][39][40][41][42][43][44], for instance, isolated single-atom Fe anchored on N-doped porous carbon and Cu-Zn clusters on porous NC [45][46][47]. Furthermore, transition metal-nitrogen-carbon (TM-N-C)-based catalysts have attracted widespread interest for CO 2 RR electrocatalysis because their 3d electron orbitals endow metal-N x (x denotes N coordination number) sites with efficient intrinsic CO 2 RR activity [48][49][50]. Therefore, the rational design of bifunctional electrocatalysts containing dual-core active sites for both CO 2 RR and ORR has significant practical applications.…”