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Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nanoparticles. Model catalysts as such are applied to catalytic transformations in the three types of catalysts: heterogeneous, homogeneous, and enzymatic. Real-time dynamics of oxidation state, coordination, and bonding of nanoparticle catalysts are put under the microscope using surface techniques such as sum-frequency generation vibrational spectroscopy and ambient pressure X-ray photoelectron spectroscopy under catalytically relevant conditions. It was demonstrated that catalytic behavior and trends are strongly tied to oxidation state, the coordination number and crystallographic orientation of metal sites, and bonding and orientation of surface adsorbates. It was also found that catalytic performance can be tuned by carefully designing and fabricating catalysts from the bottom up. Homogeneous and heterogeneous catalysts, and likely enzymes, behave similarly at the molecular level. Unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis.

A reaction model was recently been postulated to describe the phosgene synthesis process over an activated carbon catalyst. That body of work exclusively considered a single grade of activated carbon (Donau Supersorbon K40), raising the issue that the mechanistic insight gleaned could be restricted to the single substrate. Therefore, to evaluate the generality of the proposed sequence of elementary reactions that lead to phosgene production, this article concentrates on Norit RX3 Extra, a representative activated carbon that finds wide application in industrial applications. Several phosgene synthesis traits were associated with Donau Supersorbon K40 and are reproduced with Norit RX3 extra over the reaction conditions studied, such as exclusive phosgene selectivity and a degree of reagent retention. However, temperature‐programmed reaction studies show the reaction profile of the Norit RX3 extra to exhibit deviations from that observed for Donau Supersorbon K40. A modified reaction model is proposed to account for these differences. The revised reaction model is thought to represent a generic model for phosgene synthesis that can accommodate disparities in the surface chemistry of different activated carbon formulations. [ABSTRACT FROM AUTHOR]

Supported catalysts are central to industrial catalytic processes. While traditional synthesis methods often yield poorly defined materials, thus complicating structural elucidation, Surface Organometallic Chemistry (SOMC) offers a solution, producing well‐defined structures. Recent advances in SOMC precursor development have shown that amidinate‐based complexes are a privileged class of precursors to generate supported metallic nanoparticles. In that context, this study investigates the grafting mechanism of a prototypical amidinate precursor, Ir(COD)(DIA) (1‐Ir), onto SiO2. Unique to amidinate complexes, grafting is shown to occur without ligand release, creating a reversible covalent bond. Using tris(tert‐butoxy)silanol as a molecular analogue for a silanol group on SiO2, the structure of the grafted species is elucidated by single X‐Ray diffraction, comparison of IR spectroscopy, and X‐Ray absorption spectroscopy (XAS) data. The reversibility of the reaction with O−H groups is demonstrated using variable‐temperature NMR spectroscopy, IR spectroscopy, and is supported by DFT calculations. Notably, we show that a partial degrafting is also possible at elevated temperatures under vacuum. [ABSTRACT FROM AUTHOR]

While metal-rich ScAlN epitaxy has traditionally led to mixed phase films by controlling the surface chemistry with transient metal doses utilizing a pulsed method of molecular beam epitaxy, phase-pure, metal-rich epitaxy of ScAlN was demonstrated, showing improved structural and electrical characteristics. The effects of substrate temperature and III/V ratio were studied, and an x-ray diffraction figure of merit and surface roughness as low as 225 arcsec and 0.68 nm, respectively, were demonstrated. A significant catalytic effect is observed with the use of Sc in metal-rich conditions, resulting in varied growth rates with substrate temperature and Sc surface coverage. This catalytic effect results in complications when selecting synthesis conditions and for in situ monitoring and can be accounted for improved phase purity. The variation of growth rates with Sc surface coverage introduces non-linearities to the transient initiation stage of growth but also introduces a feedback stabilization of the surface chemistry. Accounting for these complexities, a Sc0.2Al0.8N high electron mobility transistor (HEMT) heterostructure is demonstrated with a sheet resistance of 152 Ω/□, a mobility of 700 cm2/Vs, and a sheet charge of 5.9 × 1013 cm−2. [ABSTRACT FROM AUTHOR]

Operando decoding of the key parameters of photo‐electric catalysis provides reliable information for catalytic effect evaluation and catalytic mechanism exploration. However, to capture the details of surface‐localized and rapid chemical and thermal events at the nanoscale in real‐time is highly challenging. A promising approach based on a lab‐around‐microfiber sensor capable of simulating photo‐electric catalytic reactions on the surface of optical fibers as well as monitoring reactant concentration changes and catalytic heat generation processes is demonstrated. Due to the penetration depth of submicron size and the fast response ability of the evanescent field, the lab‐around‐microfiber sensor overcame the difficulty of reading instantaneous surface parameters in the submicron range. This sensor operando dismantled the changes in reactant concentration and temperature on the catalyst surface induced by light and voltage, respectively. It also decoded the impact of catalyst composition on the adsorption efficiency and catalytic efficiency across various wavelengths and determined the synchronized occurrence of pollutant degradation and catalytic thermal effects. Stable correlations between the real‐time parameters and catalytic activities are obtained, helping to provide a basic understanding of the catalytic process and mechanism. This approach fills an important gap in the current monitoring methods of catalytic processes and heat production. [ABSTRACT FROM AUTHOR]

Due to the superior catalytic activity and efficient utilization of noble metals, nanocatalysts are extensively used in the modern industrial production of chemicals. The surface structures of these materials are significantly influenced by reactive adsorbates, leading to dynamic behavior under experimental conditions. The dynamic nature poses significant challenges in studying the structure–activity relations of catalysts. Herein, we unveil an anomalous entropic effect on catalysis via surface pre‐melting of nanoclusters through machine learning accelerated molecular dynamics and free energy calculation. We find that due to the pre‐melting of shell atoms, there exists a non‐linear variation in the catalytic activity of the nanoclusters with temperature. Consequently, two notable changes in catalyst activity occur at the respective temperatures of melting for the shell and core atoms. We further study the nanoclusters with surface point defects, i.e. vacancy and ad‐atom, and observe significant decrease in the surface melting temperatures of the nanoclusters, enabling the reaction to take place under more favorable and milder conditions. These findings not only provide novel insights into dynamic catalysis of nanoclusters but also offer new understanding of the role of point defects in catalytic processes. [ABSTRACT FROM AUTHOR]

This editorial discusses the importance of understanding energy dissipation and physicochemical processes at the atomic and molecular level on surfaces. The article highlights the significance of these processes in various fields such as catalysis, materials science, and nanotechnology. The editorial presents a collection of 11 articles that explore different aspects of surface dynamics, including molecular motion, water-surface interactions, electron-phonon coupling, and photoinduced reactions. The research utilizes experimental and theoretical methods to gain insights into these processes and their potential applications in areas like hydrogen production and optoelectronics. While challenges remain, further research in this field has the potential to revolutionize material fabrication and device control. [Extracted from the article]

Adsorption of metal‐organic complexes on metallic surfaces to produce well‐defined single site catalysts is a novel approach combining the advantages of homogeneous and heterogeneous catalysis. To avoid the "surface trans‐effect" a dome‐shaped molybdenum(0) tricarbonyl complex supported by an tolylazacalix[3](2,6)pyridine ligand is synthesized. This vacuum‐evaporable complex both activates CO and reacts with molecular oxygen (O2) to form a Mo(VI) trioxo complex which in turn is capable of catalytically mediating oxygen transfer. The molybdenum tricarbonyl‐ and trioxo complexes are investigated in the solid state, in homogeneous solution and on noble metal surfaces (Cu, Au) employing a range of spectroscopic and analytical methods. [ABSTRACT FROM AUTHOR]

Adsorption of metal‐organic complexes on metallic surfaces to produce well‐defined single site catalysts is a novel approach combining the advantages of homogeneous and heterogeneous catalysis. To avoid the "surface trans‐effect" a dome‐shaped molybdenum(0) tricarbonyl complex supported by an tolylazacalix[3](2,6)pyridine ligand is synthesized. This vacuum‐evaporable complex both activates CO and reacts with molecular oxygen (O2) to form a Mo(VI) trioxo complex which in turn is capable of catalytically mediating oxygen transfer. The molybdenum tricarbonyl‐ and trioxo complexes are investigated in the solid state, in homogeneous solution and on noble metal surfaces (Cu, Au) employing a range of spectroscopic and analytical methods. [ABSTRACT FROM AUTHOR]

This document is a summary of a special issue of the Catalysts journal focused on emerging catalysis-based wastewater treatment technologies. The contributions in this issue cover a range of topics, including the removal of contaminants such as arsenic, plasticizers, antibiotics, and phenol from water using various catalysts and processes. The studies evaluate the efficiency of different catalysts under different operating conditions and demonstrate their potential applications in treating environmentally relevant effluents. The authors express their gratitude to the journal and the guest editors for the opportunity to contribute to the field of environmental catalysis. [Extracted from the article]

Nanoporous silica is widely used as a support material for chemically bound stationary phases in chromatographic separations as well as for catalytic applications. Tuning of textural properties and surface chemistry of stationary phase materials (SPMs) is crucial to enhance their selectivity to certain compounds and the resulting process efficiency. Nanoporous silica supports are beneficial, as surface modifications are possible with a large variety of hydrophilic and hydrophobic functional groups, but their influence on the surface properties has not been evaluated in detail. In this sense, the contact angle is a key parameter for the assessment of surface chemistry, but its quantification in pores is challenging and requires a combination of various experimental techniques. This work demonstrates that combining water adsorption and intrusion measurements allows for the determination of the effective contact angle of adsorbed water on the pore walls for wetting, partial wetting, and nonwetting situations using functionalized hydrophilic and hydrophobic silica SPMs as model materials. Furthermore, NMR relaxometry experiments reveal that the ratio of the spin–lattice (T1) to spin–spin (T2) relaxation time of the adsorbed water film (T1,ads.film/T2,ads.film ratio) can be correlated with the effective adsorption strength of water on the surface. Indeed, a linear correlation between the negative inverse relaxation time ratio (−T2,ads.film/T1,ads.film) and the contact angle is observed. Our work demonstrates that water vapor adsorption and water intrusion experiments coupled with NMR relaxometry can be used as complementary tools to quantify the wettability and surface chemistry of nanoporous materials. This approach allows for addressing important aspects of nanoscale wettability in the context of material synthesis as well as for their application in chromatographic separation processes and catalysis. [ABSTRACT FROM AUTHOR]

Carbon materials are the key hosts for the sulfur cathode to improve the conductivity and confine the lithium polysulfides (LiPSs) in lithium–sulfur batteries (LSBs), owing to their high electronic conductivity and strong confinement effect. However, physical or chemical trapping methods have limitations in preventing the dissolution and accumulation of LiPSs in the electrolyte. Catalysis has emerged as a fundamental solution to accelerate the sluggish redox kinetics, and carbon materials acting as catalyst supports or direct catalysts significantly impact the reaction efficiency. Herein, the roles of carbon in the catalysis of LSBs are systematically discussed, focusing on the influence of surface area, pore structure, and surface chemistry on sulfur conversion. Then, two modification strategies, vacancy defects and heteroatom doping, that endow carbon with catalytic activity are summarized. Finally, the remaining challenges and solutions are outlined in terms of the preparation and characterization of the functional carbon in LSBs. This perspective provides essential insights and guidance for the rational design of carbon‐based catalysts in LSBs. [ABSTRACT FROM AUTHOR]

Controlling the coordination sphere of heterogeneous single‐metal‐site catalysts is a powerful strategy for fine‐tuning their catalytic properties but is fairly difficult to achieve. To address this problem, we immobilized supramolecular cages where the primary‐ and secondary coordination sphere are controlled by ligand design. The kinetics of these catalysts were studied in a model reaction, the hydrolysis of ammonia borane, over a temperature range using fast and precise online measurements generating high‐precision Arrhenius plots. The results show how catalytic properties can be enhanced by placing a well‐defined reaction pocket around the active site. Our fine‐tuning yielded a catalyst with such performance that the reaction kinetics are diffusion‐controlled rather than chemically controlled. [ABSTRACT FROM AUTHOR]

Catalysis is at the heart of modern-day chemical and pharmaceutical industries, and there is an urgent demand to develop metal-free, high surface area, and efficient catalysts in a scalable, reproducible and economic manner. Amongst the ever-expanding two-dimensional materials family, carbon nitride (CN) has emerged as the most researched material for catalytic applications due to its unique molecular structure with tunable visible range band gap, surface defects, basic sites, and nitrogen functionalities. These properties also endow it with anchoring capability with a large number of catalytically active sites and provide opportunities for doping, hybridization, sensitization, etc. To make considerable progress in the use of CN as a highly effective catalyst for various applications, it is critical to have an in-depth understanding of its synthesis, structure and surface sites. The present review provides an overview of the recent advances in synthetic approaches of CN, its physicochemical properties, and band gap engineering, with a focus on its exclusive usage in a variety of catalytic reactions, including hydrogen evolution reactions, overall water splitting, water oxidation, CO2 reduction, nitrogen reduction reactions, pollutant degradation, and organocatalysis. While the structural design and band gap engineering of catalysts are elaborated, the surface chemistry is dealt with in detail to demonstrate efficient catalytic performances. Burning challenges in catalytic design and future outlook are elucidated. [ABSTRACT FROM AUTHOR]

Two-dimensional nanomaterials (2D NMs), consisting of atoms or a near-atomic thickness with infinite transverse dimensions, possess unique structures, excellent physical properties, and tunable surface chemistry. They exhibit significant potential for development in the fields of sensing, renewable energy, and catalysis. This paper presents a comprehensive overview of the latest research findings on the preparation and application of 2D NMs. First, the article introduces the common synthesis methods of 2D NMs from both "top-down" and "bottom-up" perspectives, including mechanical exfoliation, ultrasonic-assisted liquid-phase exfoliation, ion intercalation, chemical vapor deposition, and hydrothermal techniques. In terms of the applications of 2D NMs, this study focuses on their potential in gas sensing, lithium-ion batteries, photodetection, electromagnetic wave absorption, photocatalysis, and electrocatalysis. Additionally, based on existing research, the article looks forward to the future development trends and possible challenges of 2D NMs. The significance of this work lies in its systematic summary of the recent advancements in the preparation methods and applications of 2D NMs. [ABSTRACT FROM AUTHOR]

Currently, catalyst design and development has drawn much attention as results of its strategic importance in the area of energy applications particular those involving biomass conversion. This work tailored exsolution of metal catalysts through the use of ceria for enhanced structural and catalytic behaviour in steam reforming of glycerol. Aside the understanding that defects due to A-site deficiency facilitates formation of vacant sites and exsolution of metal catalysts on the B-site of perovskite systems, this work has exemplified that metals such as ceria significantly influences the exsolution and general morphological surface architecture and catalytic behaviour. The exsolved nickel catalysts anchored and socketed on a titanate support and the ceria's basic surface properties and oxygen storage-release behaviour has modified the perovskite surface chemistry and enhanced catalytic behaviour particularly deactivation due to carbon deposition and reusability. Other exsolvable dopant metal species such as Fe and Co forms alloys with nickel on the surface and the synergy between the dopant metals in the alloy yielded better results. Furthermore, in one of the catalyst systems, the most commonly observed tolerable A-site deficiency and doping limit of 2% known for SrTiO 3 perovskite was overstretched by 0.5% (2.5%) thereby increasing the defect chemistry. The catalyst system with such formulation has shown a dramatic exsolution phenomenon and catalytic behaviour and robust suppression of coke deposition. CO selectivity >60% and H 2 selectivity >40% was recorded with all the catalyst systems. The catalysts used in this work are useful for applications in energy and production of value added chemicals. • Ceria enhances and mediates exsolution of nano metal catalysts. • Exsolved nono metals forms alloys with improved structural and surface chemistry. • High stability, reusability and great suppression of carbon deposition. • Overstretching of doping ratio by 0.5% enhanced defect chemistry and exsolution. [ABSTRACT FROM AUTHOR]

Montmorillonite, a ubiquitous clay mineral, has been engineered into a variety of porous and nanostructured catalysts, owing to its peculiar layered structure with characteristic surface and intercalation chemistry. Such a class of catalysts have continuously received considerable attention in both science and industry. This review examines recent advance in engineering montmorillonite into metal ion-exchanged montmorillonite catalysts, acid-activated montmorillonite catalysts, organo-montmorillonite catalysts, pillared interlayered montmorillonite catalysts and montmorillonite-supported catalysts. The former two types of montmorillonite-based catalysts have been used in the catalytic cracking, dehydration, hydrolysis, esterification, polymerization, alkylation, and Fischer-Tropic synthesis. The introduction of oxide pillars in the interlayer space of montmorillonite and the immobilization of metal oxides or zero-valent metals on the surface of montmorillonite allow montmorillonite to be used in the catalytic oxidation, reduction, isomerization and coupling reactions. Currently, the role of montmorillonite in acid catalysis, redox catalysis, and free radical catalysis have been partly revealed. The effect of the structures and the active sites of modified montmorillonite on its catalytic performance need to be investigated in more detail. Future work is suggested to focus on solving engineering problems and exploring novel catalytic applications of montmorillonite, in particular exfoliated montmorillonite nanolayers. [ABSTRACT FROM AUTHOR]

Novel energy‐storage solutions are necessary for the transition from fossil to renewable energy sources. Auspicious candidates are so‐called molecular solar thermal (MOST) systems. In our study, we investigate the surface chemistry of a derivatized norbornadiene/quadricyclane molecule pair. By using suitable push–pull substituents, a bathochromic shift of the absorption onset is achieved, allowing a greater overlap with the solar spectrum. Specifically, the adsorption and thermally induced reactions of 2‐carbethoxy‐3‐phenyl‐norbornadiene/quadricyclane are assessed on Pt(111) and Ni(111) as model catalyst surfaces by synchrotron radiation‐based X‐ray photoelectron spectroscopy (XPS). Comparison of the respective XP spectra enables the distinction of the energy‐rich molecule from its energy‐lean counterpart and allows qualitative information on the adsorption motifs to be derived. Monitoring the quantitative cycloreversion between 140 and 230 K spectroscopically demonstrates the release of the stored energy to be successfully triggered on Pt(111). Heating to above 300 K leads to fragmentation of the molecular framework. On Ni(111), no conversion of the energy‐rich compound takes place. The individual decomposition pathways of the two isomers begin at 160 and 180 K, respectively. Pronounced desorption of almost the entire surface coverage only occurs for the energy‐lean molecule on Ni(111) above 280 K; this suggests weakly bound species. The correlation between adsorption motif and desorption behavior is important for applications of MOST systems in heterogeneously catalyzed processes. [ABSTRACT FROM AUTHOR]

Low-power triethylamine (TEA) detection at room temperature (RT) is becoming increasingly significant in practical scenarios. As a novel two-dimensional material, Ti 3 C 2 T x MXene has a high potential in the field of chemical sensing at RT. It is essential to acquire the composition of the surface functional groups for Ti 3 C 2 T x since the surface chemistry is crucial for a strong interplay between the target gas and Ti 3 C 2 T x. In this work, the surface functional groups were quantitatively evaluated (approximately 40 % -O, 60 % -F) based on the combined usage of XPS analysis and DFT simulations. Ti 3 C 2 F 1.2 O 0.8 was determined to be metallic according to the calculated total density of states and band structure. A metal-semiconductor-type composite nanostructures based on the single/few-layer Ti 3 C 2 T x and Bi 2 WO 6 microcages were fabricated with different Ti 3 C 2 T x mass percentages. 0.1 wt% Ti 3 C 2 T x /Bi 2 WO 6 composite demonstrates a response enhancement by 52 % compared with the pristine Bi 2 WO 6 in the detection of 500 ppm TEA at RT. Besides, the sensitization mechanism is ascribed to the abundant surface functional groups and the catalytic effect of Ti 3 C 2 T x. • The functional groups are determined by XPS and DFT simulations (Ti 3 C 2 F 1.2 O 0.8). • 0.1 wt% Ti 3 C 2 T x /Bi 2 WO 6 composite shows a response of 2.0–500 ppm TEA at RT. • Metallic nature of Ti 3 C 2 F 1.2 O 0.8 is confirmed by DFT simulations. [ABSTRACT FROM AUTHOR]

Polydopamine (PDA)-based materials inspired by the adhesive proteins of mussels have attracted increasing attention owing to the universal adhesiveness, antioxidant activity, fluorescence quenching ability, excellent biocompatibility, and especially photothermal conversion capability. The high binding ability of PDA to a variety of metal ions offers a paradigm for the exploration of metal-chelated polydopamine nanomaterials with fantastic properties and functions. This review systematically summarizes the latest progress of metal-chelated polydopamine nanomaterials for the applications in biomedicine, catalysis, and energy storage. Different fabrication strategies for metal-chelated polydopamine nanomaterials with various composition, structure, size, and surface chemistry, such as the pre-functionalization method, the one-pot co-assembly method, and the post-modification method, are summarized. Furthermore, emerging applications of metal-chelated polydopamine nanomaterials in the fields ranging from cancer therapy, theranostics, antibacterial, catalysis to energy storage are highlighted. Additionally, the critical remaining challenges and future directions of this area are discussed to promote the further development and practical applications of PDA-based materials. [Display omitted] [ABSTRACT FROM AUTHOR]

An iridium pincer complex {p‐KO‐C6H2‐2,6‐[OP(t‐Bu)2]2}Ir(C2H4) is immobilized in a propyl bromide‐functionalized microporous polymer network using the concepts of surface organometallic chemistry. The support material enables the formation of isolated active metal sites embedded in a chemically robust and highly hydrophobic environment. The catalyst maintained high porosity and – without prior activation – exhibited high activity in the continuous‐flow dehydrogenation of cyclohexane at elevated temperatures. The catalyst shows a stable performance for at least 7 days, even when additional H2O was co‐fed, owing to its hydrophobic nature. [ABSTRACT FROM AUTHOR]

Aluminas are strategic materials used in many major industrial processes, either as catalyst supports or as catalysts in their own right. The transition alumina γ‐Al2O3 is a privileged support, whose reactivity can be tuned by thermal activation. This study provides a qualitative and quantitative assessment of the hydroxyl groups present on the surface of γ‐Al2O3 at three different dehydroxylation temperatures. The principal [AlOH] configurations are identified and described in unprecedented detail at the molecular level. The structures were established by combining information from high‐field 1H and 27Al solid‐state NMR, IR spectroscopy and DFT calculations, as well as selective reactivity studies. Finally, the relationship between the hydroxyl structures and the molecular‐level structures of the active sites in catalytic alkane metathesis is discussed. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Recent progress in colloidal synthesis has realized the preparations of uniform nanocrystal (NC) model catalysts with rich and well‐controlled morphologies that were employed to explore structure‐activity relationships of powder catalysts, similar to single‐crystal‐based model catalysts under ultrahigh vacuum conditions but can work at the same conditions as powder catalysts without the "materials gap" and "pressure gap". In this perspective, the CeO2‐based NC model catalysts with various morphologies are included and their relevant progresses are critically reviewed. The detailed descriptions of morphology‐controlled synthesis and characterizations of uniform CeO2 NCs, and morphology‐dependent catalysis of CeO2‐based NC model catalysts containing pure CeO2 NCs, CeO2‐supported oxide catalysts, and CeO2‐supported metal catalysts, provide us a comprehensive cognition in CeO2‐involved catalytic reactions and also open up a new approach for the fundamental studies of complex heterogeneous catalysis. Finally, a concept of oxide‐based NC model catalysts and outlook of oxide NCs acting not only as model catalysts for the fundamental study but also as the support in tailoring structures and optimizing performance of oxide‐involved catalysts are discussed. [ABSTRACT FROM AUTHOR]

A controlled Pd nanocubes anchoring strategy was developed for the V 2 CT x MXene nanosheets by tuning the surface chemistry, which provided a basis for the rational design of efficient MXene-supported metal nanozymes with dual nanocatalytic-photothermal activities for antibacterial uses. [Display omitted] • V 2 CT x surface chemistry was tuned by annealing. • Annealing allowed controllable synthesis of Pd nanocubes on nanosheets. • Metal-support interaction enhanced nanozyme activity and photothermal effect. • Nanocatalytic-photothermal treatment had positive synergistic effect. Rational design and controllable construction of supported nanostructures with excellent antibacterial property remain a great challenge. Recently, transition metal carbides/nitrides/carbonitrides (MXenes) have attracted much interest in many fields due to their large specific surface areas and good photothermal property. Herein, a simple yet effective surface engineering strategy based on the tuning of MXene surface chemistry is presented, which allows in-situ controlled growth of the Pd nanocubes on the V 2 CT x nanosheets. Briefly, the exfoliated V 2 CT x nanosheets by HF are annealed, which changes the composition of surface terminations while creating the mesoporous structures. The annealing largely affects the exposure and oxidation states of the adjacent V atoms and allows the controllable growth of Pd nanocubes. Interestingly, the obtained Pd@V 2 CT x nanocomposites show enhanced peroxidase-/oxidase-like activities and intrinsic photothermal effect in the near infra-red (NIR) region due to the strong metal-support interaction. Furthermore, the combined nanocatalytic-photothermal treatment by their versatilities remarkably improves the antibacterial efficacy, giving a high killing rate (above 98 % for both Escherichia coli and Staphylococcus aureus). This work provides a new avenue to develop the supported metal nanostructures based on MXenes for antibacterial application. [ABSTRACT FROM AUTHOR]

Molecular adsorption on surfaces plays an important part in catalysis, corrosion, desalination, and various other processes that are relevant to industry and in nature. As a complement to experiments, accurate adsorption energies can be obtained using various sophisticated electronic structure methods that can now be applied to periodic systems. The adsorption energy of water on boron nitride substrates, going from zero to 2-dimensional periodicity, is particularly interesting as it calls for an accurate treatment of polarizable electrostatics and dispersion interactions, as well as posing a practical challenge to experiments and electronic structure methods. Here, we present reference adsorption energies, static polarizabilities, and dynamic polarizabilities, for water on BN substrates of varying size and dimension. Adsorption energies are computed with coupled cluster theory, fixed-node quantum Monte Carlo (FNQMC), the random phase approximation, and second order Møller-Plesset theory. These wavefunction based correlated methods are found to agree in molecular as well as periodic systems. The best estimate of the water/h-BN adsorption energy is -107±7 meV from FNQMC. In addition, the water adsorption energy on the BN substrates could be expected to grow monotonically with the size of the substrate due to increased dispersion interactions, but interestingly, this is not the case here. This peculiar finding is explained using the static polarizabilities and molecular dispersion coefficients of the systems, as computed from time-dependent density functional theory (DFT). Dynamic as well as static polarizabilities are found to be highly anisotropic in these systems. In addition, the many-body dispersion method in DFT emerges as a particularly useful estimation of finite size effects for other expensive, many-body wavefunction based methods. [ABSTRACT FROM AUTHOR]

Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nanoparticles. Model catalysts as such are applied to catalytic transformations in the three types of catalysts: heterogeneous, homogeneous, and enzymatic. Real-time dynamics of oxidation state, coordination, and bonding of nanoparticle catalysts are put under the microscope using surface techniques such as sum-frequency generation vibrational spectroscopy and ambient pressure X-ray photoelectron spectroscopy under catalytically relevant conditions. It was demonstrated that catalytic behavior and trends are strongly tied to oxidation state, the coordination number and crystallographic orientation of metal sites, and bonding and orientation of surface adsorbates. It was also found that catalytic performance can be tuned by carefully designing and fabricating catalysts from the bottom up. Homogeneous and heterogeneous catalysts, and likely enzymes, behave similarly at the molecular level. Unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis.

The influence of the interface in ZnO−ZrO2 catalysts for the selective hydrogenation of CO2 to CH3OH is investigated. Specifically, we perturbed its structure using two different synthetic methods: surface organometallic chemistry (SOMC) and flame‐spray pyrolysis (FSP) and investigated the speciation of the resulting materials by spectroscopic techniques, such as XAS, NMR, IR, UV‐Vis, and EPR. The results indicate that oxidic Zn particles that co‐exist with ZrO2, as synthesized by FSP, show a superior selectivity in contrast to Zn(0) nanoparticles or Zn(II) single sites on ZrO2, formed using SOMC. Further experiments underlined the importance of the ZnO−ZrO2 interface in the process: only materials with such an interface exhibit highly selective production of CH3OH, proceeding likely via the formation of the surface CH3O intermediates. [ABSTRACT FROM AUTHOR]

Epoxidation reactions are tremendously important for modern chemistry, as they lead to series of highly useful bulk and fine chemicals, monomers, and intermediates for organic synthesis. Progress in epoxidation processes goes hand in hand with the advancement made in catalysis science. In this context, heterogeneous catalysts, and particularly Ti‐based formulations, are playing a central role and have seen tremendous developments over the past two decades, leveraging on advanced materials science. The aim of this review is to illustrate the various strategies of titanosilicate catalysts preparation that can lead to more versatile, more performant, and greener epoxidation processes. We successively cover (i) supported catalysts, obtained by the grafting of Ti species onto preformed silica supports, (ii) microporous crystalline titanosilicates (zeolites), and (iii) amorphous titanosilicates obtained by sol‐gel chemistry. For each category, with an emphasis on catalyst preparation, the challenges that have to be tackled to boost catalyst performance are highlighted. From that point, we present a critical review of the different approaches that have been proposed in the primary literature to tailor the properties that govern catalysts performance (activity, selectivity, stability, ease of handling). This is done by better controlling the nature of the active surface species, adapting particles size and shape, optimizing texture, modifying surface chemistry, etc. These lines of attack encompass molecular approaches for the grafting of well‐defined species, top‐down and bottom‐up synthesis of hierarchically porous zeolites, advanced sol‐gel routes potentially performed in non‐conventional media or coupled with original processing, preparation of self‐standing monoliths, etc. Future research directions are discussed with emphasis on the application scope of new catalytic materials and possible approaches to increase catalyst performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Wall-flow channeled monoliths with trimodal pore-size distribution. • SiC monoliths with core-skin hierarchical macroporosity allow membrane coating. • Homogeneous loading of SiO 2 or Al 2 O 3 nanoparticles into the SiC macropores. • Texture defined by SiC porosity, nanoparticle composition, size and load, and calcination temperature. • Efficient Rh-catalyst immobilization, hydroformylation integrated membrane reactor feasible. Monolithic support materials with the mechanical resistance and thermal conductivity of SiC as well as tunable surface chemistry and textural properties were developed for their use in catalytic membrane reactors. After heat treatment, the extruded SiC monoliths have a monomodal distribution of macropores of a few μm in diameter depending on the particle size of the starting material. A macroporous, defect-free, smoother skin was applied onto the external wall using a solution of sub-micrometer SiC particles. These monoliths with skin could be coated successfully with molecularly selective membranes, and thus have application in membrane reactor processes. Finally, metal oxide nanoparticles were infiltrated into the macropores to modify the surface texture and chemistry, allowing the immobilization of liquid phase catalysts. The resulting multimodal distribution of pore sizes could be tuned by the choice of SiC and oxide particle sizes, number of wash-coats and calcination temperature. Mesopores created between nanoparticles had diameters of roughly 40 % of those of the nanoparticles. Small macropores, between 10−1000 nm, were also created, with bigger size and volume at higher calcination temperatures due to the metal oxide particles contraction. The developed materials were validated as support for PDMS membranes and for continuous gas-phase hydroformylation of 1-butene using Rh-diphosphite catalysts. [ABSTRACT FROM AUTHOR]

A molecular-level understanding of how the electronic structure of metal center tunes the catalytic behaviors remains a grand challenge in heterogeneous catalysis. Herein, we report an unconventional kinetics strategy for bridging the microscopic metal electronic structure and the macroscopic steady-state rate for CO oxidation over Pt catalysts. X-ray absorption and photoelectron spectroscopy as well as electron paramagnetic resonance investigations unambiguously reveal the tunable Pt electronic structures with well-designed carbon support surface chemistry. Diminishing the electron density of Pt consolidates the CO-assisted O2 dissociation pathway via the O*-O-C*-O intermediate directly observed by isotopic labeling studies and rationalized by density-functional theory calculations. A combined steady-state isotopic transient kinetic and in situ electronic analyses identifies Pt charge as the kinetics indicators by being closely related to the frequency factor, site coverage, and activation energy. Further incorporation of catalyst structural parameters yields a novel model for quantifying the electronic effects and predicting the catalytic performance. These could serve as a benchmark of catalyst design by a comprehensive kinetics study at the molecular level. A molecular-level understanding of the electronic effects remains a grand challenge in heterogeneous catalysis. Here, the authors report an unconventional kinetics strategy for bridging the upscaling gap between the microscopic fingerprints of active sites and the macroscopic catalytic performance. [ABSTRACT FROM AUTHOR]

Summary: Artificial photo-driven water oxidation has been proposed over half a century through a four-charge involved multiple-step oxygen evolution process. However, the knowledge of the intrinsic activity, such as the rate-law of the water oxidation reactions, has been inadequately studied. Up to date, the highest order reported is the third one under photoelectrochemical condition. In this work, we identified the fourth-order charge decay reactions on hematite by using a time-resolved surface photovoltage probe technique. A theoretical turnover frequency (TOF) > 100 nm−2·s−1 can be expected for O2 molecules when the hole density >0.1 nm−2. This work demonstrates a facile and robust method to investigate the high-order reaction kinetics. More excitingly, this research built the bridge between the rate-law, rate-determining step, and energy barrier of intermediates.

[Display omitted] • 3D distribution of atoms dispels energy to cleave bonds through electron transfer. • Bioelectrocatalysis depends on the spatial arrangement of the catalytic pocket. • Electrocatalysis in 3D systems can be more effective than on flat surfaces. The exceptional catalysis for the oxygen reduction reaction (ORR) of bilirubin oxidase (BOD) encouraged us to reevaluate the existing catalytic models. Experimental evidence of the electron-transfer reaction's dependence on the three-dimensional structure of BOD is demonstrated by operando X-ray absorption spectroscopy (XAS) combined with Quantum Mechanics/Molecular Mechanics (QM/MM). We suggest that if a catalytic reaction occurs in a three-dimensional environment (3D-catalysis), the energies involved in the transition states during the electron transfer cannot be explained by adsorption kinetics. In contrast, there is the formation of a three-dimensional complex (TDC). Our data suggest influence of the metallic cofactor electronic structure as well as the spatial disposition of its surrounding ligands on the electron transfer that promotes the biocatalysis. We propose that investigating enzymatic redox processes involving a dynamic three-dimensional enzymatic structure can provide further insights as how heterogeneous catalysis can work beyond single atoms and surface chemistry. [ABSTRACT FROM AUTHOR]

The development of ingenious technologies for the purification of wastewater containing highly toxic organic compounds is of high importance in the current research. The application of noble metal nanocatalysts in the presence of sodium borohydride (NaBH4) for the removal of these toxic compounds through chemical reduction method have become an accepted approach in the recent years. The present work reports on the development of a convenient approach to fabricate free standing, robust, and flexible reduced graphene oxide ‐ silver/polyvinyl alcohol (rGO−Ag/PVA) nanocomposite film. The morphological and structural characterizations of the as developed film have been carried out using SEM, TEM, EDAX, Raman, BET, and TGA. The performance of as developed rGO−Ag/PVA nanocomposite film is tested as heterogeneous catalyst in the reduction reaction of 4‐Nitrophenol and reduction of Methyl Orange dye. The nanocomposite film‐based catalyst exhibited excellent catalytic performances as well as excellent stability in the reduction of toxic organic compounds in wastewater. [ABSTRACT FROM AUTHOR]