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Carbonic anhydrase (CA) is an important carbon fixation enzyme. Immobilization of CA can expand its application in the realm of adsorption, catalysis, and so on. As a typical metal-free framework, hydrogen-bonded organic frameworks (HOFs) featuring mild synthesis process, exquisite framework structure and good enzyme compatibility have been used for enzyme embedding. However, the catalytic performance of CA-embedded HOFs (CA@HOFs) is limited by the micropore size of HOFs and the slow adsorption of CO₂. Herein, CA@Lys-HOF-1 was synthesized by introducing lysine (Lys), a basic amino acid, during the coprecipitation of CA and HOFs for CO₂ fixation. The addition of Lys enlarged the average pore size of HOF-1 from 1.8 to 3.2 nm, whereas the introduced -NH₂ groups increased the initial adsorption of CO₂ from 0.55 to 1.21 cm³ g^-1. Compared to CA@HOF-1, the activity of CA@Lys-HOF-1 was enhanced by 71.25%, and the corresponding production of CaCO₃ was enhanced by 12.7%. After eight reaction cycles, CA@Lys-HOF-1 still maintained an output of 9.97 mg of CaCO₃ every 5 min, 83.7% of the initial production. It is hoped that the CA@Lys-HOF-1 reported offers a platform for efficient and continuous fixation of CO₂. LESS      Full article

Direct hydrazine fuel cell is a promising portable energy conversion device due to its high energy density and free of carbon emissions. To realize the practical applications, the design of highly efficient electrocatalysts for hydrazine oxidation reaction (HzOR) is crucial. Metal nanocrystals with high-index facets have abundant step sites with reactivity. In this study, we prepared trapezohedral Pt nanocrystals (TPH Pt NCs) enclosed by {311} high-index facets and investigated the catalytic performance for hydrazine oxidation. TPH Pt NCs possess a specific activity of 39.1 mA·cm^-2 at 0.20 V, much higher than {111}-faceted octahedral (13.9 mA·cm^-2) and {100}-faceted cubic Pt NCs (9.11 mA·cm^-2). Meanwhile, TPH Pt NCs also show superior stability. Density functional theory (DFT) calculation indicates that Pt(311) facilitates the deprotonation of N₂H₄* to N₂H₃* (the rate-determining step) and improves the HzOR activity. This study is helpful for the design of advanced electrocatalysts for HzOR, especially high-index faceted Pt nanocatalysts. LESS      Full article

The synergistic promotion by photocatalysis and thermocatalysis is a promising approach for sustainable hydrogen (H₂) production. Herein, we rationally design a perovskite-based catalyst with three-dimensionally ordered macroporous structure (3DOM CaTiO₃-Au) for photothermal catalytic H₂ production from different substrates. The hierarchical 3DOM structure facilitates light harvesting and mass diffusion of the substrates, while the gold nanoparticles (Au NPs) promote charge separation. The photogenerated and hot electrons are oriented accumulated on the surface of Au NPs. The non-metallic gold species [Au(I)] show more activity for H₂ evolution. As a result, 3DOM CaTiO₃-Au exhibits excellent activity for H₂ production from glycerol and other substrates with hydroxyl groups. The present work demonstrates a feasible approach to improve sustainable H₂ production by rationally designing and fabricating efficient photothermal catalysts. LESS      Full article

MFI zeolite characterized by uniform pore size, adjustable acidity, and high-temperature resistance has a broad application prospect in catalytic reactions. However, controlling the product distribution of zeolite as a catalyst is still confronting great challenges and applications. It is considered as an effective way to control the product distribution by developing and improving new zeolites to modulate their shape selective effect. In recent years, researchers have achieved remarkable successes in investigating the shape selective modulation of zeolites on catalytic reaction and molecular diffusion. The microporous channels of MFI zeolite are the main places for the entry and exit of reactants or product molecules. This review provides the research progress of the shape-selective modulation of MFI zeolite channels and its influence on a series of catalytic performances in recent years. The shape-selective modulation of microporous channels of zeolite, encapsulation of micropores to metals, catalysis of mesoporous zeolite, and the distribution of framework Al were all systematically discussed. The development of advanced catalysts still faces great challenges and potential applications. Finally, we discussed the problems to be addressed urgently in the field of zeolite catalysts in the future. LESS      Full article

As a new kind of organic-inorganic hybrid porous material, metal-organic frameworks (MOFs) exhibit a wide application prospect in gas storage and separation, catalysis and sensing due to their characteristics of large specific surface area, high porosity and coordination unsaturation. As more and more types of MOFs were reported, the synthetic strategies of MOFs-based materials have become a hot research topic. According to the morphological dimension, MOFs can be roughly divided into one-dimensional, two-dimensional and three-dimensional structures. Herein, we summarize the synthetic methods and principles of MOFs from multi-dimensional perspectives, and explore the growth mechanism of MOFs with different morphologies based on dynamic and thermodynamic tuning. Finally, based on the above summaries, the challenges and opportunities of MOFs in the future are discussed. LESS      Full article

For more than four decades, the methanol-to-hydrocarbons (MTH) reaction has been a successful route to producing valuable fuels and chemicals from non-petroleum feedstocks. This review provides the most comprehensive summary to date of recent research concerning the mechanistic fundamentals of this important reaction, covering different reaction stages. Mechanisms that have been proposed to explain the initial C-C bond formation during the induction stage of the MTH reaction are introduced, including the methoxymethyl cation, Koch carbonylation, carbene and methane-formaldehyde processes. At present, there is no consensus regarding these hypothetical mechanisms as a consequence of the limited amount of conclusive experimental evidence. The steady state of the MTH reaction is also examined with a focus on the widely accepted indirect hydrocarbon pool mechanism and the dual cycle concept that provides a mechanistic basis for the effects of zeolite structures and reaction conditions on product distribution. In the following section, advanced characterization techniques capable of providing new insights into the formation of coke species during the MTH reaction and innovative approaches effectively inhibiting coke formation are introduced. Finally, a summary is provided and perspectives on current challenges and the future development of this area are presented. LESS      Full article

Owing to the intrinsic complexity of crystallization and the heterogeneity of precursors, the specific stages and corresponding behaviors of an actual crystallization system remain ambiguous, which makes the univariate-controlled crystallization-kinetics-regulated synthesis and design of zeolite morphology and porosity an unrealized blueprint. In this study, a facile and univariate modulation (i.e., OH^-/SiO₂) strategy was developed to regulate zeolite crystallization kinetics, and zeolite L mesocrystals were synthesized rapidly (within 1-2 h) with almost all LTL morphologies (from cylindrical or disc-like shapes to nanoclusters or nanocrystals) in the simplest SiO₂-Al₂O₃-K₂O-H₂O system. Using time-resolved analysis of the change in the solid-liquid Si/Al nutrient and crystallinity evolution, the intertwined and complex crystallization processes of zeolite L were clearly distinguished into four distinct stages: induction, nucleation, growth, and ripening. Under alkalinity-controlled conditions, the reactivity, Si/Al distribution, and state of aluminosilicates were critical to the formation of short-range order in the amorphous matrix, which greatly influenced the nucleation frequency and assembly state. Subsequently, these nucleation differences evoked correspondingly different kinetic growth behaviors. A putative alkalinity-controlled nonclassical crystallization mechanism was uncovered, and its validity was evaluated by analyzing morphology evolution, NH₄F etching, and the effects of modifiers. Furthermore, adsorption tests demonstrated the high adsorption capacity of a series of zeolite L for guest molecules with various sizes and properties (e.g., gaseous aromatic hydrocarbon, aqueous dye, and protein). LESS      Full article

The emission of CO₂ has become an increasingly prominent issue. Electrochemical reduction of CO₂ to value-added chemicals provides a promising strategy to mitigate energy shortage and achieve carbon neutrality. Two-dimensional (2D) materials are highly attractive for the fabrication of catalysts owing to their special electronic and geometric properties as well as a multitude of edge active sites. Various 2D materials have been proposed for synthesis and use in the conversion of CO₂ to versatile carbonous products. This review presents the latest progress on various 2D materials with a focus on their synthesis and applications in the electrochemical reduction of CO₂. Initially, the advantages of 2D materials for CO₂ electro-reduction are briefly discussed. Subsequently, common methods for the synthesis of 2D materials and the role of these materials in the electrochemical reduction of CO₂ are elaborated. Finally, some perspectives for future investigations of 2D materials for CO₂ electro-reduction are proposed. LESS      Full article

A novel supramolecular self-assembly nanostructure of porous helical nanoribbons (PHNRs) was developed. PHNRs from oligoaniline derivatives were fabricated through the chemical oxidation of aniline in an i-propanol/water mixture as mediated by β-cyclodextrin (β-CD). The role of β-CD was considered vital through the modulation of the addition time point of β-CD and the molar ratio of β-CD/aniline. In addition, at the early stage of polymerization, the host-guest complex between oligoaniline and β-CD was formed, which was involved in the initial supramolecular assembly process. However, with the reorganization of the oligoaniline assemblies during the polymerization time, the abscission of β-CD from the helical nanoribbons was observed, which eventually induced the formation of PHNRs. We believe the supramolecular host-modulated assembly strategy presented herein will be instructive for the fabrication of porous supramolecular nanostructures. LESS      Full article