Facile Synthesis of Hierarchical Nanosized Single‐Crystal Aluminophosphate Molecular Sieves from Highly Homogeneous and Concentrated Precursors

The synthesis of hierarchical nanosized zeolite materials without growth modifiers and mesoporogens remains a substantial challenge. Herein, we report a general synthetic approach to produce hierarchical nanosized single‐crystal aluminophosphate molecular sieves by preparing highly homogeneous and concentrated precursors and heating at elevated temperatures. Accordingly, aluminophosphate zeotypes of LTA (8‐rings), AEL (10‐rings), AFI (12‐rings), and ‐CLO (20‐rings) topologies, ranging from small to extra‐large pores, were synthesized. These materials show exceptional properties, including small crystallites (30–150 nm), good monodispersity, abundant mesopores, and excellent thermal stability. A time‐dependent study revealed a non‐classical crystallization pathway by particle attachment. This work opens a new avenue for the development of hierarchical nanosized zeolite materials and understanding their crystallization mechanism.     

Highly Mesoporous Metal-Organic Frameworks as Synergistic Multimodal Catalytic Platforms for Divergent Cascade Reactions

Rational engineering and assimilation of diverse chemo- and biocatalytic functionalities in a single nanostructure is highly desired for efficient multistep chemical reactions but has so far remained elusive. Here, we design and synthesize multimodal catalytic nanoreactors (MCNRs) based on a mesoporous metal-organic framework (MOF). The MCNRs consist of customizable metal nanocrystals and stably anchored enzymes in the mesopores, as well as coordinatively unsaturated cationic metal MOF nodes, all within a single nanoreactor space. The highly intimate and diverse catalytic mesoporous microenvironments and facile accessibility to the active site in the MCNR enables the cooperative and synergistic participation from different chemo- and biocatalytic components. This was shown by one-pot multistep cascade reactions involving a heterogeneous catalytic nitroaldol reaction followed by a [Pd/lipase]-catalyzed chemoenzymatic dynamic kinetic resolution to yield optically pure (>99 % ee) nitroalcohol derivatives in quantitative yields.     

Large-Scale Synthesis of MOF-Derived Superporous Carbon Aerogels with Extraordinary Adsorption Capacity for Organic Solvents

Carbon aerogels (CAs) with 3D interconnected networks hold promise for application in areas such as pollutant treatment, energy storage, and electrocatalysis. In spite of this, it remains challenging to synthesize high-performance CAs on a large scale in a simple and sustainable manner. We report an eco-friendly method for the scalable synthesis of ultralight and superporous CAs by using cheap and widely available agarose (AG) biomass as the carbon precursor. Zeolitic imidazolate framework-8 (ZIF-8) with high porosity is introduced into the AG aerogels to increase the specific surface area and enable heteroatom doping. After pyrolysis under inert atmosphere, the ZIF-8/AG-derived nitrogen-doped CAs show a highly interconnected porous mazelike structure with a low density of 24 mg cm⁻³, a high specific surface area of 516 m² g⁻¹, and a large pore volume of 0.58 cm⁻³ g⁻¹. The resulting CAs exhibit significant potential for application in the adsorption of organic pollutants.     

Combined Alkali‐Organoammonium Structure Direction of High‐Charge‐Density Heteroatom‐Containing Aluminophosphate Molecular Sieves

The charge density mismatch concept was applied to the synthesis of high‐charge‐density silicoaluminophosphate SAPO‐69 (OFF) and SAPO‐79 (ERI) and zincoaluminophosphate PST‐16 (CGS), PST‐17 (BPH), PST‐19 (SBS), and ZnAPO‐88 (MER) molecular sieves. Combined alkali‐organoammonium structure direction in these systems is thus enabled. Structure direction is treated from the perspective of stabilizing an ionic framework, the relationships between reaction charge density (OH^?/H₃PO₄), alkali and organoammonium content, and ionicity of tetrahedral framework atoms in successful structure direction are presented.     

Cooperative Catalysis of an Alcohol Dehydrogenase and Rhodium‐Modified Periodic Mesoporous Organosilica

The combined use of a metal‐complex catalyst and an enzyme is attractive, but typically results in mutual inactivation. A rhodium (Rh) complex immobilized in a bipyridine‐based periodic mesoporous organosilica (BPy‐PMO) shows high catalytic activity during transfer hydrogenation, even in the presence of bovine serum albumin (BSA), while a homogeneous Rh complex exhibits reduced activity due to direct interaction with BSA. The use of a smaller protein or an amino acid revealed a clear size‐sieving effect of the BPy‐PMO that protected the Rh catalyst from direct interactions. A combination of Rh‐immobilized BPy‐PMO and an enzyme (horse liver alcohol dehydrogenase; HLADH) promoted sequential reactions involving the transfer hydrogenation of NAD⁺ to give NADH followed by the asymmetric hydrogenation of 4‐phenyl‐2‐butanone with high enantioselectivity. The use of BPy‐PMO as a support for metal complexes could be applied to other systems consisting of a metal‐complex catalyst and an enzyme.     

Synthesis and Characterization of Magnesium Substituted Aluminophosphate Molecular Sieves with AEL Structure

MAPO-11 molecular sieves were synthesized by hydrothermal methods. The influence of precursor of magnesium, Mg/Al ratio, synthesis temperature, synthesis time and the type of template on the formation and properties of MAPO-11 molecular sieves was examined. The samples were characterized by the techniques of X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric/differential thermogravimetric analysis (TG-DGA), etc. The results show that the shape and size of crystal were influenced by the precursor of Mg, the Mg/Al ratio and the type of template, and the TG-DGA analysis shows that MAPO-11 molecular sieves as-synthesized have poor thermal stability.     

多级孔磷酸铝分子筛的合成、表征及催化应用

同时含有微孔和介孔的多级孔磷酸铝分子筛由于能减少微孔磷酸铝分子筛在涉及大分子的催化反应中的扩散限制,近年来逐渐成为人们的研究热点。本文主要阐述了多级孔磷酸铝分子筛的合成、表征和催化应用方面的最新进展。根据多级孔的生成机制,将多级孔磷酸铝分子筛的合成方法分成了四类,即硬模板法、软模板法、无模板法和后处理法,并对这些方法的优缺点进行了系统的比较。以磷酸硅铝分子筛为例,评述了各种表征多级孔分子筛的酸性和孔结构的方法。最后,对多级孔磷酸硅铝分子筛在三类重要的催化反应(即烷基化反应、异构化反应和甲醇制烯烃)中的研究进展进行了综述。     

Highly Selective Enamination of β‐ketoesters Catalyzed by Interlocked [Cu8] and [Cu18] Nanocages

Interlocking cages are of great interest due to their fascinating structures and potential applications. However, the interlocking of different cages has not been previously reported. Herein, quadruply interlocked [Cu₈] and [Cu₁₈] nanocages have been constructed and structurally characterized in cationic metal–organic framework {[Cu^ICu₄^II(XN)₄(PTA)₄(H₂O)₄]0.5 SO₄?5 H₂O?EtOH}_n ( 1 ). 1 can trap the anionic pollutant CrO₄^2? and the radioactive‐contaminant simulant ReO₄^? with an uptake capacity of 83.2 and 218 mg g^?1, respectively. Catalytic investigations reveal 1 is an efficient heterogeneous catalyst for the enamination of ethyl acetoacetate with aniline and the turnover frequency (TOF) can reach a record value of 4000 h^?1. More importantly, 1 represents the first of a catalyst of enamination to exhibit excellent size selectivity on different substrates. The robust catalyst can be reused at least ten times without obvious loss in catalytic activity.     

Bridging Dealumination and Desilication for the Synthesis of Hierarchical MFI Zeolites

The rational design of zeolite‐based catalysts calls for flexible tailoring of porosity and acidity beyond micropore dimension. To date, dealumination has been applied extensively as an industrial technology for the tailoring of zeolite in micropore dimension, whereas desilication has separately shown its potentials in the creation of mesoporosities. The free coupling of dealumination with desilication will bridge the tailoring at micro/mesopore dimensions; however, such coupling has been prevailingly confirmed as an impossible mission. In this work, a consecutive dealumination–desilication process enables the introduction of uniform intracrystalline mesopores (4–6 nm) into the microporous Al‐rich zeolites. The decisive impacts of steaming step have been firstly discovered. These findings revitalize the functions of dealumination in porosity tailoring, and stimulate the pursuit of new methods for the tailoring of industrially relevant Al‐rich zeolites.