The structure-directing role of heterologous seeds in the synthesis of zeolite

Zeolites have been widely used as catalysts,ion-exchangers,and adsorbents in chemical industries,detergent industry,steel industry,glass industry,ceramic industry,medical and healthfield,and environmentalfield,and recently applied in energy storage.Seed-assisted synthesis is a very effective approach in promoting the crystallization of zeolites.In some cases,the target zeolite cannot be formed in the absence of seed zeolite.In homologous seed-assisted synthesis,the structure of the seed zeolite is the same to that of the target zeolite,while the structure of the seed zeolite is different to that of the target zeolite in the heterologous seed-assisted synthesis.In this review,we briefly summarized the heterologous seed-assisted syntheses of zeolites and analyzed the structure-directing effect of heterologous seeds and surveyed the“common composite building units(CBUs)hypothesis”and the“common secondary building units(SBUs)hypothesis”.However,both hypotheses cannot explain all observations on the heterologous seed-assisted syntheses.Finally,we proposed that the formation of the target zeolite does need nuclei with the structure of target zeolite and the formation of the nuclei of the target zeolite can be promoted by either the undissolved seed crystals with the same CBUs or SBUs to the target zeolite or by the facilitated appropriate distribution of the specific building units due to the presence of the heterologous seed that does not have any common CBUs and SBUs with the target zeolite.

电子自旋效应在电催化剂中的作用

高效电催化剂的开发对于能源转换及储存技术的发展至关重要。自旋作为粒子的内禀性质,能够对化学反应的过程产生独特的影响。因此,调控电催化剂内部自旋状态能够有效提升催化剂整体性能。本综述首先介绍了电子自旋以及自旋调控的影响因素,随后从热力学和动力学两方面阐述了自旋效应在电催化中的作用机理。进一步,我们综述了自旋效应在氧还原反应(ORR)、析氧反应(OER)、氮还原反应(NRR)、二氧化碳还原反应(CO_(2)RR)中的最新研究进展,详细介绍了自旋调控在上述四种反应中的催化机理。同时本文总结了电子自旋的先进表征方法和自旋催化的第一性原理计算方法。最后,我们展望了自旋效应在电催化领域的发展趋势。因此,认识并了解电子自旋效应有助于加深对电催化反应过程的机制理解,指导设计高效催化剂,具有巨大的研究价值。

Defect Engineering on Carbon‑Based Catalysts for Electrocatalytic CO2 Reduction

Electrocatalytic carbon dioxide(CO2)reduction(ECR)has become one of the main methods to close the broken carbon cycle and temporarily store renewable energy,but there are still some problems such as poor stability,low activity,and selectivity.While the most promising strategy to improve ECR activity is to develop electrocatalysts with low cost,high activity,and long-term stability.Recently,defective carbon-based nanomaterials have attracted extensive attention due to the unbalanced electron distribution and electronic structural distortion caused by the defects on the carbon materials.Here,the present review mainly summarizes the latest research progress of the construction of the diverse types of defects(intrinsic carbon defects,heteroatom doping defects,metal atomic sites,and edges detects)for carbon materials in ECR,and unveil the structure-activity relationship and its catalytic mechanism.The current challenges and opportunities faced by high-performance carbon materials in ECR are discussed,as well as possible future solutions.It can be believed that this review can provide some inspiration for the future of development of high-performance ECR catalysts.

Synergism of Pt nanoparticles and iron oxide support for chemoselective hydrogenation of nitroarenes under mild conditions

An efficient and low-cost supported Pt catalyst for hydrogenation of niroarenes was prepared with colloid Pt precursors andα-Fe2O3 as a support.The catalyst with Pt content as low as 0.2 wt%exhibits high activities,chemoselectivities and stability in the hydrogenation of nitrobenzene and a variety of niroarenes.The conversion of nitrobenzene can reach 3170 molconv h^–1 molPt^–1 under mild conditions(30°C,5 bar),which is much higher than that of commercial Pt/C catalyst and many reported catalysts under similar reaction conditions.The spatial separation of the active sites for H2 dissociation and hydrogenation should be responsible for the high chemoselectivity,which decreases the contact possibility between the reducible groups of nitroarenes and Pt nanoparticles.The unique surface properties ofα-Fe2O3 play an important role in the reaction process.It provides active sites for hydrogen spillover and reactant adsorption,and ultimately completes the hydrogenation of the nitro group on the catalyst surface.

Oxidative coupling of alcohols and amines to an imine over Mg-Al acid-base bifunctional oxide catalysts

A series of Mg‐Al mixed oxide catalysts are prepared and introduced as efficient irreducible catalysts for the oxidative coupling of alcohols and amines to imine.The structure and surface properties of Mg‐Al oxides are modulated by changing the Mg/Al ratios,calcination temperature and treatment with probe molecules.Detailed characterization,including X‐ray diffraction,27Al magic angle spinning nuclear magnetic resonance spectroscopy,N2‐adsorption,NH3‐temperature‐programmed desorption,CO2‐temperature‐programmed desorption and X‐ray photoelectron spectroscopy are carried out to determine the physicochemical properties of these catalysts.The Mg‐Al oxides with Mg/Al=3exhibit the highest activity in the reaction,which possess a large number of surface weak basic sites and a relatively small number of weak acidic sites.The role of the acidic and basic sites in the reaction process is systematically investigated,and are shown to serve as adsorption and activation sites for amines and alcohols,respectively.Under the synergistic effect of these acid‐base centers,the oxidative coupling process successfully occurs on the surface of Mg‐Al mixed oxides.Compared with the acidic sites,the weak basic sites play a more important role in the catalytic process.The acidic sites are the catalytic centers for the benzyl alcohol activation,which control the reaction rate of the oxidative coupling reaction.

Interfacial-interaction-induced fabrication of biomass-derived porous carbon with enhanced intrinsic active sites

Carbon catalysis is an attractive metal-free catalytic transformation,and its performance is significantly dependent on the number of accessible active sites.However,owing to the inherent stability of the C-C linkage,only limited active sites at the edge defects of the basal plane can be obtained even after a harsh oxidation treatment.In this study,the concept of interfacial interactions was adopted to propose an efficient strategy to develop highly active carbon catalysts.The alumina/carbon interface formed in situ acted as a cradle for the generation of oxygen-containing functional groups.In the absence of oxidation treatment,the concentration of oxygen-containing functional groups and the specific surface area can reach 1.27 mmol·g^(-1) and 2340 m^(2)·g^(-1),respectively,which are significantly higher than those of carbon prepared by traditional hard template methods.This active carbon shows a significant enhancement in catalytic performance in the oxidative coupling of amine to imine,about 22-fold higher than that of a well-known graphite oxide catalyst.Such interfacial interaction strategies are based on sustainable carbon sources and can effectively tune the porous structure of carbon in the micro-and meso-ranges.This conceptual finding offers new opportunities for the development of high-performance carbon-based metal-free catalysts.

Polydopamine modified Au/FAU catalytic membrane for CO preferential oxidation

A hollow-fiber-supported stable Au/FAU catalytic membrane was successfully synthesized through a polydopamine coating modification-removal strategy and used as a flow-through catalytic membrane reactor for preferential oxidation of CO.Small Au nanoparticles can be efficiently isolated by dopamine and the dopamine-derived carbon shells.The interactions between Au nanoparticles and zeolite layer support are enhanced during annealing at high temperature under an inert atmosphere.A zeolite membrane supported Au nanoparticle catalyst was obtained after the removal of carbon shells,which showed high catalytic activity and stability for the removal of CO from hydrogen.

Boosting selective C_(2)H_(2)/CH_(4),C_(2)H_(4)/CH_(4) and CO_(2)/CH_(4) adsorption performance via 1,2,3-triazole functionalized triazine-based porous organic polymers

Nitrogen-rich porous organic polymers have shown great potentials in gas adsorption/separation,photocatalysis,electrochemistry,sensing and so on.Herein,1,2,3-triazole functionalized triazine-based porous organic polymers(TT-POPs)have been synthesized by the copper-catalyzed azide-alkyne cycloaddition(Cu-AAC)polymerization reactions of 1,3,5-tris(4-azidophenyl)-triazine with 1,4-diacetylene benzene and 1,3,5-triacetylenebenzene,respectively.The characterizations of N2 adsorption at 77 K show TTPOPs possess permanent porosity with BET surface areas of 666 m^(2)·g^(-1)(TT-POP-1)and 406 m^(2)·g^(-1)(TT-POP-2).The adsorption capacities of TT-POPs for CO_(2),CH4,C2H2 and C2H4,as well as the selective separation abilities of CO_(2)/N2,CO_(2)/CH_(4),C_(2)H_(2)/CH_(4) and C_(2)H_(4)/CH_(4) were evaluated.The gas selective separation ratio of TT-POPs was calculated by the ideal adsorbed solution theory(IAST)method,wherein the selective separation ratios of C_(2)H_(2)/CH_(4) and C_(2)H_(4)/CH_(4) of TT-POP-2 was 48.4 and 13.6(298 K,0.1 MPa),which is comparable to other adsorbents(5.6–120.6 for C_(2)H_(2)/CH_(4),10–26 for C_(2)H_(4)/CH_(4)).This work shows that the 1,2,3-triazole functionalized triazine-based porous organic polymer has a good application prospect in natural gas purification.

Zeolites for the separation of ethylene,ethane,and ethyne

The cost-effective separation of ethylene(C_(2)H_(4)),ethyne(C_(2)H_(2)),and ethane(C_(2)H_(6))poses a significant challenge in the contemporary chemical industry.In contrast to the energy-intensive high-pressure cryogenic distillation process,zeolite-based adsorptive separation offers a low-energy alternative.This review provides a concise overview of recent advancements in the adsorptive separation of C_(2)H_(4),C_(2)H_(2),and C_(2)H_(6)using zeolites or zeolite-based adsorbents.It commences with an examination of the industrial significance of these compounds and the associated separation challenges.Subsequently,it systematically examines the utilization of various types of zeolites with diverse cationic species in such separation processes.And then it explores how different zeolitic structures impact adsorption and separation capabilities,considering principles such as cation-πinteraction,π-complexation,and steric separation concerning C_(2)H_(4),C_(2)H_(2),and C_(2)H_(6)molecules.Furthermore,it discusses methods to enhance the separation performance of zeolites and zeolite-based adsorbents,encompassing structural design,modifications,and ion exchange processes.Finally,it summarizes current research trends and future directions,highlighting the potential application value of zeolitic materials in the field of C_(2)H_(4),C_(2)H_(2),and C_(2)H_(6)separation and offering recommendations for further investigation.

Mechanism of interfacial effects in sodium-ion storage devices

Rechargeable sodium-ion batteries(SIBs)are considered as the next-generation secondary batteries.The performance of SIB is determined by the behavior of its electrode surface and the electrode–electrolyte interface during charging and discharging.Thus,the characteristics of these surfaces and interfaces should be analyzed to realize large-scale energy storage systems with high energy density and long-cycle stability.Although various studies have investigated the properties of electrode materials,few studies have focused on the construction of stable and efficient SIB interfaces,and even fewer have explored the mechanisms of interfacial effects;however,the strategies of regulating interfacial effects are yet to be completely developed.Moreover,the results obtained thus far are insufficient to draw systematic conclusions.The present study reviews the literature on the mechanism of interfacial effects in Na+storage devices.The interfaces in a sodium-ion storage device include a heterogeneous interface between electrode materials,a solid electrolyte interphase,and a cathode electrolyte interphase.The interfacial effects during the intercalation,transformation,and alloy reactions and the resulting overall battery performance were theoretically analyzed.In this review,we aim to provide a theoretical basis for optimizing the structures of electrode surface and electrode–electrolyte interface to optimize the performance of SIBs.In addition,the challenges of investigating interfacial effects and several possible helpful methods and opportunities for studying the mechanisms of interfacial effects in SIBs will be presented.

凝聚液态水溶液中的化学反应

液态水是进行化学反应的最重要介质与溶剂之一,也是研究在凝聚(液)态中进行化学反应的主要对象。在不同的外界条件下(特别是极端条件下),液态水的组成、结构与性能会发生很大的变化,促使在其中进行的化学反应呈现不同的特点,因而形成了温和条件下、水热条件下(Hydrothermal condition)与超临界水热条件下(Supercritical water codition)三大类型反应的凝聚态化学。本文立足凝聚态,讨论了在温和(一般)条件下,液态水与水溶液的组成、结构与性能对发生于其中的化学反应(包括溶解与结晶反应、盐类复分解反应、酸碱反应、沉淀反应、成胶与晶化反应、水解反应、氧化-还原反应以及配位化学反应)的影响,包括对反应物存在状态与化学活性,化学反应的过程与机理,反应的中间与最后产物的组成、结构等造成的影响,以及产生的结果与规律等有关的反应化学。通过这些讨论我们提出应从凝聚态的角度看待发生于液态水溶液中的化学反应,并希望这种新视角对研究在其他类型液体(诸如有机溶剂、离子液体、分子熔体等)中进行的化学反应时有所帮助,同时能加强彼此间的交流、讨论与批判,协力为推动以液态为主要研究对象的凝聚态化学的研究与学科建设提供有益的基础。

Rational confinement engineering of MOF-derived carbonbased electrocatalysts toward CO_(2)reduction and O_(2)reduction reactions

The goal of global carbon peak and neutrality gives an impetus to the utilization of clean energy(e.g.,fuel cell)and carbon dioxide(CO_(2))at a large scale,where the oxygen reduction reaction(ORR)and CO_(2)reduction reaction(CO_(2)RR)are the key reactions via the sustainable system,respectively.As a main precursor for fabricating affordable carbon-based electrocatalysts with uniformly dispersed active centers and tailorable performances for ORR and CO_(2)RR,metal organic frameworks(MOFs)have captured a surge of interest in recent years.Despite the facilitated development of MOF-derived carbon-based electrocatalysts by many investigations,it is still plagued by high overpotential and unsatisfied life span,which are greatly determined by the efficient and alterable confinement effect on synthesis and performance.In this review,firstly,the confined synthetic strategies(doping engineering,defect engineering,geometric engineering,etc.)of MOF-derived carbon-based electrocatalysts with multi-sized active centers(atom,atomic clusters and nanoparticles(NPs))are systematically summarized;secondly,the confinement effect on the interaction of ORR and CO_(2)RR intermediates,as well as the catalytic durability and activity,was discussed from chemical and physical aspects.In the end,the review discusses the remaining challenges and emerging research topics in the future,including support upgradation and catalyst innovation,high selectivity and effective confinement synthesis,in situ and operando characterization techniques,theoretical investigation,and artificial intelligence(AI)assistant.The new understanding and insights into these aspects will guide the rational confinement concept of MOF-derived carbon-based electrocatalysts for ORR and CO_(2)RR with optimized performances in terms of confinement engineering and are believed to be helpful for filling the existing gaps between scientific communities and practical use.

Catalytic effect of carbon-based electrode materials in energy storage devices

The catalytic effect of electrode materials is one of the most crucial factors for achieving efficient electrochemical energy conversion and storage.Carbon-based metal composites were widely synthesized and employed as electrode materials because of their inherited outstanding properties.Usually,electrode materials can provide a higher capacity than the anticipated values,even beyond the theoretical limit.The origin of the extra capacity has not yet been explained accurately,and its formation mechanism is still ambiguous.Herein,we first summarized the current research progress and drawbacks in energy storage devices(ESDs),and elaborated the role of catalytic effect in enhancing the performance of ESDs as follows:promoting the evolution of the solid electrolyte interphase(SEI),accelerating the reversible conversion of discharge/charge products,and improving the conversion speed of the intermediate and the utilization rate of the active materials,thereby avoiding the shuttling effect.Additionally,a particular focus was placed on the interaction between the catalytic effect and energy storage performance in order to highlight the efficacy and role of the catalytic effect.We hope that this review could provide innovative ideas for designing the electrode materials with an efficient catalytic effect for ESDs to promote the development of this research field.

Anionic Tuning of Zeolite Crystallization

Zeolites are of great industrial relevance as catalysts,adsorbents,and ion-exchangers and typically synthesized under hydrothermal conditions.Rational regulation of their crystallization process is of great significance for zeolite production.In this work,we systematically investigate the role of anions in tuning zeolite crystallization via anion introduction including SO_(4)^(2−),F^(−),Cl^(−),Br^(−),I^(−),and SCN^(−) in the sodium form into the SiO2-TPAOH-H2O[tetrapropylammonium hydroxide(TPAOH)]synthetic system of silicalite-1 zeolite.