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The development of efficient electrocatalysts with non‐copper metal sites for electrochemical CO2 reduction reactions (eCO2RR) to hydrocarbons and oxygenates is highly desirable, but still a great challenge. Herein, a stable metal–organic framework (DMA)4[Sn2(THO)2] (Sn‐THO, THO6− = triphenylene‐2,3,6,7,10,11‐hexakis(olate), DMA = dimethylammonium) with isolated and distorted octahedral SnO62− active sites is reported as an electrocatalyst for eCO2RR, showing an exceptional performance for eCO2RR to the CH4 product rather than the common products formate and CO for reported Sn‐based catalysts. The partial current density of CH4 reaches a high value of 34.5 mA cm−2, surpassing most reported copper‐based and all non‐Cu metal‐based catalysts. Our experimental and theoretical results revealed that the isolated SnO62− active site favors the formation of key *OCOH species to produce CH4 and can greatly inhibit the formation of *OCHO and *COOH species to produce *HCOOH and *CO, respectively. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 to CO is a promising approach for the cycling use of CO2, while it still suffers from impractical current density and durability. Here we report a single‐atom nanozyme (Ni−N5−C) that achieves industrial‐scale performance for CO2‐to‐CO conversion with a Faradaic efficiency (FE) exceeded 97 % over −0.8–−2.4 V vs. RHE. The current density at −2.4 V vs. RHE reached a maximum of 1.23 A cm−2 (turnover frequency of 69.7 s−1) with an FE of 99.6 %. No obvious degradation was observed over 100 hours of continuous operation. Compared with the planar Ni−N4 site, the square‐pyramidal Ni−N5 site has an increase and a decrease in the dz2 ${{{\rm d}}_{{z}^{2}}}$ and dxz/yz orbital energy levels, respectively, as revealed by density functional theory calculations. Thus, the Ni−N5 catalytic site is more superior to activate CO2 molecule and reduce the energy barriers as well as promote the CO desorption, thus boosting the kinetic activation process and catalytic activity. [ABSTRACT FROM AUTHOR]

Porous coordination polymers (PCPs) or metal–organic frameworks (MOFs) have been widely used as catalysts for their large porosities, uniform pore sizes/shapes, diversified/tunable pore surfaces, redox properties, and other unique structural features. Accompanying the urgent need for clean and sustainable technologies for energy storage and conversion, as well as the fast improvement of the chemical stability of these materials, MOFs and their composites are emerging as unique electrocatalysts for the hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, carbon dioxide reduction reaction, and some other redox reactions. This review summaries representative progress and focuses on the structure–property relationships. Combining the advantages of inorganic heterogeneous and molecular homogeneous catalysts, MOFs can serve as a promising platform for achieving high electrocatalytic performances and studying the electrocatalytic mechanisms. More attention should be devoted to designing new MOFs with high chemical stability and electric conductivity, and optimizing their crystal growth on conducting substances. [ABSTRACT FROM AUTHOR]

The paddle-wheel type cluster Co2(RCOO)4(LT)2 (R = substituent group, LT = terminal ligand), possessing unusual metal coordination geometry compared with other cobalt compounds, may display high catalytic activity but is highly unstable especially in water. Here, we show that with judicious considerations of the host/guest geometries and modular synthetic strategies, the labile dicobalt clusters can be immobilized and stabilized in a metal-organic framework (MOF) as coordinative guests. The Fe(na)4(LT) fragment in the MOF [{Fe3(μ3-O)(bdc)3}4{Fe(na)4(LT)}3] (H2bdc = 1,4-benzenedicaboxylic acid, Hna = nicotinic acid) can be removed to give [{Fe3(μ3-O)(bdc)3}4] with a unique framework connectivity possessing suitable distribution of open metal sites for binding the dicobalt cluster in the form of Co2(na)4(LT)2. After two-step, single-crystal to single-crystal, postsynthetic modifications, a thermal-, water-, and alkaline-stable MOF [{Fe3(μ3-O)(bdc)3}4{Co2(na)4(LT)2}3] containing the desired dicobalt cluster was obtained, giving extraordinarily high electrocatalytic oxygen evolution activity in water at pH = 13 with overpotential as low as 225 mV at 10.0 mA cm-2. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 to CO is a promising approach for the cycling use of CO2, while it still suffers from impractical current density and durability. Here we report a single‐atom nanozyme (Ni−N5−C) that achieves industrial‐scale performance for CO2‐to‐CO conversion with a Faradaic efficiency (FE) exceeded 97 % over −0.8–−2.4 V vs. RHE. The current density at −2.4 V vs. RHE reached a maximum of 1.23 A cm−2 (turnover frequency of 69.7 s−1) with an FE of 99.6 %. No obvious degradation was observed over 100 hours of continuous operation. Compared with the planar Ni−N4 site, the square‐pyramidal Ni−N5 site has an increase and a decrease in the dz2 and dxz/yz orbital energy levels, respectively, as revealed by density functional theory calculations. Thus, the Ni−N5 catalytic site is more superior to activate CO2 molecule and reduce the energy barriers as well as promote the CO desorption, thus boosting the kinetic activation process and catalytic activity. [ABSTRACT FROM AUTHOR]