Microenvironments Enabled by Covalent Organic Framework Linkages for Modulating Active Metal Species in Photocatalytic CO₂ Reduction

Abstract

Covalent organic frameworks (COFs) are promising platforms for understanding photocatalytic CO 2 reduction processes owing to their predesignable structures and tailor-made functions. Herein, a nickelmodified COF composed of N-acylhydrazone-linked electron-donor and electron-acceptor dyads (H-COF-Ni) is reported. H-COF-Ni generates 5694 µmol g −1 of CO with 96% selectivity over H 2 evolution in 2 h under visible light irradiation, which greatly outperforms that of typical iminelinked counterpart. Experimental and theoretical results have demonstrated that metal active sites in host frameworks are deprived by 2,2′-bipyridine additive to form new catalytic active species, the separation and transfer process of the photogenerated charge carriers are not main reason for their activity difference. The linkage-dependent activation of CO 2 molecules on Ni centers is responsible for high photocatalytic efficiency. This study provides new protocols to improve CO 2 photoreduction performance through the modification of linkage microenvironments.

Hollow Nanoboxes Cu2‐xS@ZnIn2S4 Core‐Shell S‐Scheme Heterojunction with Broad‐Spectrum Response and Enhanced Photothermal‐Photocatalytic Performance

“…However, it has also resulted in a slew of environmental issues, including pollution and a scarcity of resources. [1][2][3][4][5][6][7][8] As a Because they have enough free electrons to support the visible and NIR areas, noble metal materials like gold and silver are the most widely employed materials in localized surface plasmon resonance (LSPR) research. [25] By turning light energy into thermal energy, LSPR can be employed as an extra energy input to improve photocatalytic performance.…”

Tailoring defect-type and ligand-vacancies in Zr(iv) frameworks for CO2 photoreduction

“…52 All the LUMO potentials of the as-synthetized samples are more negative than the redox potential of CO 2 to CO (À0.53 V vs. NHE), hinting at the possibility of their CO 2 photoreduction potency. [53][54][55][56] Photoelectrochemical measurements were performed to probe the photogenerated electron separation and transfer behavior in the defect samples. As shown in Fig.…”

“…52 All the LUMO potentials of the as-synthetized samples are more negative than the redox potential of CO 2 to CO (−0.53 V vs. NHE), hinting at the possibility of their CO 2 photoreduction potency. 53–56…”

Metalated covalent organic frameworks: from synthetic strategies to diverse applications

“…Inspired by this insight into the structure–property relationship, in 2022, Wang et al further investigated the CO 2 RR activity of Ni( ii )-metalated COFs with different coordination linkages. 605 H-COF-Ni containing β-ketoenamine–Ni( ii ) has a higher CO yield (5694 vs. 1960 μmol g −1 in 2 h) and slightly lower selectivity (87 vs. 93%) than I-COF-Ni with imine–Ni( ii ). The coordination environment provided by β-ketoenamine linkage was more favorable for CO 2 adsorption, activation, and photoreduction than that of imine linkage, leading to a higher CO 2 RR performance of H-COF-Ni than I-COF-Ni.…”