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Energy‐saving and value‐added management in advanced catalysis is highly desirable but is challenged by the limitations of multifunctional catalysts and catalytic modules. Herein, an azo‐linked phthalocyanine‐porphyrin covalent organic framework (COF) with the ultrathin layered nanostructure grown on carbon nanotubes (NiPc‐azo‐H2Pp@CNTs) has been designed and synthesized, which can serve as a highly active and stable bifunctional heterojunction electrocatalyst for selective paired‐electrosynthesis through coupling anodic iodide oxidation reaction and cathodic CO2 conversion. Particularly, the inbuilt local microenvironment conferred by the dihydroporphyrin moieties in COF can act as a proton reservoir to promote the proton relay at the heterojunction interface during the electrocatalytic process. Moreover, through the cascade construction of dual electrocatalytic/organocatalytic modules, the cathode‐generated CO can be further converted to dimethyl carbonate with a yield of 6.21 mmol L−1 h−1, while the anode‐produced iodine can be derived into iodoform on the hundred‐milligram scale. It is worth noting that the value‐added cascade synthesis mediated by paired‐electrolysis using the distinctive and high‐powered electrocatalysts will help advance the sustainable development of industrial intelligent manufacturing. [ABSTRACT FROM AUTHOR]

• A single-atom catalyst with ultrathin nanosheet structure and high Ni loading of 5.92 wt%. • High catalytic performance with CO Faradaic efficiency over 95 % in a wide potential range. • Remarkable CO yields up to 1146 mmol g cat –1 h–1. • Unveiling modulation effect of the electronic configuration of Ni-N 4 active sites by F-doping. A fluorine-tuned single-atom catalyst with an ultrathin nanosheet morphology (only ∼1.25 nm) and high Ni content of 5.92 wt% was fabricated by a polymer-assisted pyrolysis approach. The synthetic approach not only controls the establishment of the ultrathin nanosheet structure for achieving high surface communication, but also incorporates F dopants to manipulate the electronic structure of the metalloporphyrin-like active sites (Ni-N 4). As a result, such catalyst with unique structural features exhibits a remarkable electrocatalytic performance for CO 2 -to-CO conversion with the Faradaic efficiency (FE) over 95 % in a wide potential range and an outstanding CO evolution rate of 1146 mmol g cat –1 h–1 at –0.97 V vs. RHE. The in situ attenuated total reflection-infrared spectroscopy (ATR-IR) and theoretical calculations further demonstrate that the F-doping modulates the electron configuration of the central Ni-N 4 sites and thereby reduces the energy barrier for CO 2 activation, which is favorable to the generation of the key *COOH intermediate. [ABSTRACT FROM AUTHOR]

• Immobilization of the functionalized phthalocyanine at the single-molecular level. • Nearly 100 % Faradaic efficiency for electrocatalytic CO 2 reduction. • A ultrahigh CO/H 2 ratio of 640 at –0.88 V. How to efficiently obtain the value-added products through electrocatalytic CO 2 reduction is highly desired while remains significant challenges. Herein, we report an extremely active and selective immobilized pyrrolidinonyl nickel phthalocyanine (PyNiPc) catalyst for electrocatalytic CO 2 reduction, which was constructed by a built-in pyrrolidone group-assisted assembly strategy and presented single-molecular level dispersion of PyNiPc on carbon nanotubes. The resulting catalyst can predominantly produce CO in the electrocatalytic CO 2 reduction, affording nearly 100 % Faradaic efficiency over a wide potential range with ultrahigh CO/H 2 ratios up to 640. Besides, the extraordinary activity with a turnover frequency value of 1.3 × 104 h–1 at –0.93 V and durability were also achieved. Investigations unraveled the promotion effect of pyrrolidone groups in dispersion and catalysis. The reaction pathways over this catalyst were further explored by using in situ attenuated total reflection-infrared spectroscopy. This work offers a new understanding for constructing both active and selective molecular-based electrocatalysts. [ABSTRACT FROM AUTHOR]