Peng Tan

Hydrogen-bonded organic frameworks (HOFs) are promising porous materials for gas separation, but their low thermal conductivity results in high regeneration energy consumption. This work fabricates a flexible-HOF-based magnetic adsorbent (MN@FHOF-x) and utilizes magnetically induced heating to achieve the efficient adsorption swing of the HOF component in C₂H₆ capture. Fe₃O₄ nanoparticles were embedded in the HOF-FJU-1 particles, which have a 3-fold interpenetrated rhombic network structure and feature reversible open/closed pore transformation. At 25 °C without a magnetic field, the open-pore structure of HOF-FJU-1 provides abundant adsorption sites for C₂H₆. Under an alternating magnetic field, Fe₃O₄ nanoparticles generate heat rapidly via Néel relaxation, inducing the HOF framework to transform into a closed-pore state and release C₂H₆. The optimal sample exhibits a working capacity of 9.3 cm³ g^-1 (25-50 °C), outperforming some representative adsorbents such as ZIF-7 (6.5 cm³ g^-1) and NUM-9 (8.5 cm³ g^-1). This study provides a structure-performance-tailored strategy for developing advanced adsorbents for gas separation by combining flexible porous frameworks with magnetic nanoheaters.

Enzyme immobilization in metal-organic frameworks (MOFs) features improved catalytic efficiency, enhanced stability, and good recyclability. However, remote modulation of enzymatic activity in a confined space has never been reported, despite its great significance in biochemical systems. Here we develop a photoresponsive system with remote controllability in terms of the activity of an enzyme in a confined space. The photoresponsive inhibitor (PRI) is decorated on the pore walls of a mesoporous MOF, PCN-128, followed by the introduction of an enzyme (carbonic anhydrase (CA)). Upon visible-light irradiation, PRI is in its trans state and docks at the active site of CA, inhibiting the enzymatic activity. Upon exposure to UV-light radiation, PRI undergoes isomerization to its cis configuration and subsequently dissociates from the enzyme's active site, leading to a 66.7% enhancement in its catalytic activity. In contrast, free inhibitors demonstrate poor regulating performance. This strategy enables reversible regulation of the enzyme's natural function in a confined space through light-controlled noncovalent interactions.

Mg and its related solid base catalysts have always been thought of with weak or medium basicity. Herein, we present the synthesis of Mg single atom catalyst (Mg₁/NPC) with strong basicity by tuning its coordination environment, which shows unusual activity in strong‐base‐catalyzed transesterification reaction. Mg₁/NPC were obtained through impregnation‐pyrolysis method, results manifest Mg single atoms are embedded in nitrogen doped carbon in penta‐coordination (Mg‐C₃N₂) which endows Mg single atoms with strong basicity and is in contrast to traditional alkaline‐earth metal oxides. The novel Mg₁/NPC exhibits excellent activity (40.2%) and stability in transesterification of methanol and ethylene carbonate to produce dimethyl carbonate (DMC), outperforming all state‐of‐the‐art Mg‐based solid base catalysts thus far reported as well as Ca, Na, and K‐based catalysts with superbasicity (2.5%–39.2%). This work might pave the way for the advancement of novel solid base catalysts with extraordinary sources of basicity for multifarious applications.

Enzymes have flexible structures and can modulate the multiple catalytic sites efficiently for synergistic catalysis. Inspired by enzymes, various artificial catalysts have been designed, while controllable synergistic effects in artificial catalysts have never been reported. Here, we report the first example of photo‐regulated synergistic catalyst (PRSC) and the synergistic effects between acidic and basic sites can be regulated by light. PRSCs have acidic sites on pore walls and basic sites on pendant azobenzene groups, and photo‐regulation is achieved through azobenzene isomerization. In the cascade reaction of converting benzaldehyde dimethyl acetal (BA) to benzylidenemalononitrile (BM), the PRSC shows a change of up to 33.6% in BM yield. Mechanism exploration indicates that cis azobenzene makes the catalytic system more stable. The promoted adsorption energy of the reactant malononitrile (MN) on basic sites and the activated C atom of MN that connects to methylene groups are responsible for the tunable synergistic effects of PRSCs.