Metal-free catalysts are of great importance and alternative candidates to conventional metal-based catalysts for many reactions. Herein, several types of metal–organic frameworks have been exploited as templates/precursors to afford porous carbon materials with various nitrogen dopant forms and contents, degrees of graphitization, porosities, and surface areas. Amongst these materials, the PCN-224-templated porous carbon material optimized by pyrolysis at 700 °C (denoted as PCN-224-700) is composed of amorphous carbon coated with well-defined graphene layers, offering a high surface area, hierarchical pores, and high nitrogen content (mainly, pyrrolic nitrogen species). Remarkably, as a metal-free catalyst, PCN-224-700 exhibits a low activation energy and superior activity to most metallic catalysts in the catalytic reduction of 4-nitrophenol to 4-aminophenol. Theoretical investigations suggest that the content and type of the nitrogen dopant play crucial roles in determining the catalytic performance and that the pyrrolic nitrogen species makes the dominant contribution to this activity, which explains the excellent efficiency of the PCN-224-700 catalyst well.

Composite nanomaterials usually possess synergetic properties resulting from the respective components and can be used for a wide range of applications. In this work, a Pd nanocubes@ZIF-8 composite material has been rationally fabricated by encapsulation of the Pd nanocubes in ZIF-8, a common metal–organic framework (MOF). This composite was used for the efficient and selective catalytic hydrogenation of olefins at room temperature under 1 atm H₂ and light irradiation, and benefits from plasmonic photothermal effects of the Pd nanocube cores while the ZIF-8 shell plays multiple roles; it accelerates the reaction by H₂ enrichment, acts as a “molecular sieve” for olefins with specific sizes, and stabilizes the Pd cores. Remarkably, the catalytic efficiency of a reaction under 60 mW cm⁻² full-spectrum or 100 mW cm⁻² visible-light irradiation at room temperature turned out to be comparable to that of a process driven by heating at 50 °C. Furthermore, the catalyst remained stable and could be easily recycled. To the best of our knowledge, this work represents the first combination of the photothermal effects of metal nanocrystals with the favorable properties of MOFs for efficient and selective catalysis.

Composite nanomaterials usually possess synergetic properties resulting from the respective components and can be used for a wide range of applications. In this work, a Pd nanocubes@ZIF-8 composite material has been rationally fabricated by encapsulation of the Pd nanocubes in ZIF-8, a common metal–organic framework (MOF). This composite was used for the efficient and selective catalytic hydrogenation of olefins at room temperature under 1 atm H₂ and light irradiation, and benefits from plasmonic photothermal effects of the Pd nanocube cores while the ZIF-8 shell plays multiple roles; it accelerates the reaction by H₂ enrichment, acts as a “molecular sieve” for olefins with specific sizes, and stabilizes the Pd cores. Remarkably, the catalytic efficiency of a reaction under 60 mW cm⁻² full-spectrum or 100 mW cm⁻² visible-light irradiation at room temperature turned out to be comparable to that of a process driven by heating at 50 °C. Furthermore, the catalyst remained stable and could be easily recycled. To the best of our knowledge, this work represents the first combination of the photothermal effects of metal nanocrystals with the favorable properties of MOFs for efficient and selective catalysis.

A sulfone-functionalized metal–organic framework (MOF), USTC-253, has been synthesized that exhibits a much higher CO₂ uptake capacity (168–182 %) than the corresponding unfurnished MOFs. The introduction of trifluoroacetic acid (TFA) during the synthesis of USTC-253 affords defect-containing USTC-253-TFA with exposed metal centers, which has an increased CO₂ uptake (167 %) compared to pristine USTC-253. USTC-253-TFA exhibits a very high ideal adsorption solution theory selectivity (S=75) to CO₂ over N₂ at 298 K. In addition, USTC-253-TFA demonstrates good catalytic activity and recyclability in the cycloaddition of CO₂ and epoxide at room temperature under 1 bar CO₂ pressure as a result of the presence of Lewis and Brønsted acid sites, which were evaluated by diffuse reflectance infrared Fourier transform spectroscopy with a CO probe molecule. We propose that the CO₂ adsorption capability has a positive correlation with the catalytic performance toward CO₂ conversion.

Different alkylamine molecules were post-synthetically tethered to the unsaturated Cr^III centers in the metal–organic framework MIL-101. The resultant metal–organic frameworks show almost no N₂ adsorption with significantly enhanced CO₂ capture under ambient conditions as a result of the interaction between amine groups and CO₂ molecules. Given the extraordinary stability, high CO₂ uptake, ultrahigh CO₂/N₂ selectivity, and mild regeneration energy, MIL-101-diethylenetriamine holds exceptional promise for post-combustion CO₂ capture and CO₂/N₂ separation.

For the first time, a ∼100 % sulfonic acid functionalized metal–organic framework (MOF), MIL-101-SO₃H, with giant pores has been prepared by a hydrothermal process followed by a facile postsynthetic HCl treatment strategy. The replete readily accessible Lewis acidic and especially Brønsted acidic sites distributed throughout the framework as well as high stability endow the resultant MOF exceptionally high efficiency and recyclability, which surpass all other MOF-based catalysts, for the ring opening of epoxides with alcohols (especially, methanol) as nucleophiles under ambient conditions.