Ethanol synthesis catalytic CO hydrogenation over multi-elemental KFeCuZn/ZrO catalyst.

Technological enablers that use CO as a feedstock to create value-added chemicals, including ethanol, have gained widespread appeal. They offer a potential solution to climate change and promote the development of a circular economy. However, the conversion of CO to ethanol poses significant challenges, not only because CO is a thermodynamically stable and chemically inert molecule but also because of the complexity of the reaction routes and uncontrollability of C-C coupling.

Exploring Catalytic Intermediates in Pd-Catalyzed Aerobic Oxidative Amination of 1,3-Dienes: Multiple Metal Interactions of the Palladium Nanoclusters.

Metal nanoclusters (NCs) have unique properties because of their small size, which makes them useful as catalysts in reactions like cross-coupling. Pd-catalyzed oxidative amination, which involves dehydrogenative C-N bond formation, uses Pd complexes as the active species. It is known that the catalytic conditions involve the formation of Pd(0) species from Pd NCs, but the precise role of Pd NCs in the transformations has not been established.

Propane dehydrogenation catalysis of group IIIB and IVB metal hydrides.

Catalytic propane dehydrogenation (PDH) has mainly been studied using metal- and metal oxide-based catalysts. Studies on dehydrogenation catalysis by metal hydrides, however, have rarely been reported. In this study, PDH reactions using group IIIB and IVB metal hydride catalysts were investigated under relatively low-temperature conditions of 450 °C.

Low-Temperature Methane Combustion Using Ozone over Coβ Catalyst.

Catalytic methane (CH) combustion is a promising approach to reducing the release of unburned methane in exhaust gas. Here, we report Co-exchanged β zeolite (Coβ) as an efficient catalyst for CH combustion using O. A series of ion-exchanged β zeolites (Co, Ni, Mn, Fe, and Pd) are subjected to the catalytic test, and Coβ exhibits a superior performance in a low-temperature region (<100 °C).

High ionic conduction in a robust anionic metal-organic framework containing Mg under guest vapors.

We report on the synthesis and high ionic conductivity of a highly crystalline Mg-containing metal-organic framework (MOF) with Type A feature (, anionic framework having Mg as a counter cation). We synthesized Mg[Zr(CHO)] (SU-102-Mg) through ion exchange reaction. SU-102-Mg showed a high ionic conductivity of 3.

Microporosity and Catalytic Activity for Hydrodesulfurization of Pharmacosiderite MoPO Synthesized at a Moderate Temperature.

Pharmacosiderite MoPO (Pharma-MoPO) consists of [MoO] cubane unit and [PO] tetrahedral to form an open framework with a microporous structure similar to that of LTA-type zeolite. Although attractive applications are expected due to its microporous structure and redox-active components, its physicochemical properties have been poorly investigated due to the specificity of its synthesis, which requires a high hydrothermal synthesis temperature of 360 °C. In this study, we succeeded in synthesizing Pharma-MoPO by hydrothermal synthesis at 230 °C, which can be applied using a commercially available autoclave by changing the metal source.

The Development of the Regenerable Catalytic System in Selective Catalytic Oxidation of Ammonia with High N Selectivity.

Supported particulate noble-metal catalysts are widely used in industrial catalytic reactions. However, these metal species, whether in the form of nanoparticles or highly dispersed entities, tend to aggregate during reactions, leading to a reduced activity or selectivity. Addressing the frequent necessity for the replacement of industrial catalysts remains a significant challenge.

Active site tuning based on pseudo-binary alloys for low-temperature acetylene semihydrogenation.

The development of an efficient catalytic system for low-temperature acetylene semihydrogenation using nonnoble metals is important for the cost-effective production of polymer-grade pure ethylene. However, it remains challenging owing to the intrinsic low activity. Herein, we report a flexibly tunable catalyst design concept based on a pseudo-binary alloy, which enabled a remarkable enhancement in the catalytic activity, selectivity, and durability of a Ni-based material.

Catalytic ammonia synthesis on HY-zeolite-supported angstrom-size molybdenum cluster.

The development of new catalysts with high N activation ability is an effective approach for low-temperature ammonia synthesis. Herein, we report a novel angstrom-size molybdenum metal cluster catalyst for efficient ammonia synthesis. This catalyst is prepared by the impregnation of a molybdenum halide cluster complex with an octahedral Mo metal core on HY zeolite, followed by the removal of all the halide ligands by activation with hydrogen.

Feeble Single-Atom Pd Catalysts for H Production from Formic Acid.

Single-atom catalysts are thought to be the pinnacle of catalysis. However, for many reactions, their suitability has yet to be unequivocally proven. Here, we demonstrate why single Pd atoms (Pd) are not catalytically ideal for generating H from formic acid as a H carrier.

In Situ Spectroscopic Study of CO Capture and Methanation over Ni-Ca Based Dual Functional Materials.

Carbon dioxide capture and reduction (CCR) to CH using dual-functional materials (DFMs) have recently attracted significant attention as a promising strategy for carbon capture and utilization. In this study, we investigate the mechanism of CCR to CH over AlO-supported Ni-Ca DFMs (Ni-Ca/AlO) under cyclic feeds of model combustion exhaust (2.5 % CO+0 or 10 % O/N) and H at 500 °C.

Continuous Unsteady-State De-NO System via Tandem Water-Gas Shift, NH Synthesis, and NH-SCR under Periodic Lean/Rich Conditions.

The development of urea-free and platinum group metal (PGM)-free catalytic systems for automotive emission control is a challenging task. Herein, we report a new de-NO system using cyclic feeds of rich and lean gas mixtures with PGM-free catalysts. Initial catalyst screening tests showed that Cu/CeO with 5 wt % Cu loading was the most suitable for the water-gas shift reaction (WGS, CO + HO → CO + H), followed by the selective NH synthesis by the NO + H reaction.

Mechanism of NH-SCR over P/CeO Catalysts Investigated by Spectroscopies.

This study reports a comprehensive investigation into the active sites and reaction mechanism for the selective catalytic reduction of NO by NH (NH-SCR) over phosphate-loaded ceria (P/CeO). Catalyst characterization and density functional theory calculations reveal that HPO and HPO species are the dominant phosphate species on the P/CeO catalysts under the experimental conditions. The reduction/oxidation half-cycles (RHC/OHC) were investigated using X-ray absorption near-edge structure for Ce L-edge, ultraviolet-visible, and infrared (IR) spectroscopies together with online analysis of outlet products ( spectroscopy).

Accelerated discovery of multi-elemental reverse water-gas shift catalysts using extrapolative machine learning approach.

Designing novel catalysts is key to solving many energy and environmental challenges. Despite the promise that data science approaches, including machine learning (ML), can accelerate the development of catalysts, truly novel catalysts have rarely been discovered through ML approaches because of one of its most common limitations and criticisms-the assumed inability to extrapolate and identify extraordinary materials. Herein, we demonstrate an extrapolative ML approach to develop new multi-elemental reverse water-gas shift catalysts.

Bifunctionality of Re Supported on TiO in Driving Methanol Formation in Low-Temperature CO Hydrogenation.

Low temperature and high pressure are thermodynamically more favorable conditions to achieve high conversion and high methanol selectivity in CO hydrogenation. However, low-temperature activity is generally very poor due to the sluggish kinetics, and thus, designing highly selective catalysts active below 200 °C is a great challenge in CO-to-methanol conversion. Recently, Re/TiO has been reported as a promising catalyst.

Prediction of Stable Surfaces of Metal Oxides through the Unsaturated Coordination Index.

This study proposes the unsaturated coordination index, σ, as a potential descriptor of the stability of metal-oxide surfaces cleaved from bulk. The value of σ, the number of missing bonds per unit area, can be obtained very quickly using only crystallographic data, namely, the bulk geometry. The surface energies of various binary oxides, with and without atom relaxation, were calculated.

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Dynamic behavior of intermediate adsorbates, such as diffusion, spillover, and reverse spillover, has a strong influence on the catalytic performance in oxide-supported metal catalysts. However, it is challenging to elucidate how the intermediate adsorbates move on the catalyst surface and find active sites to give the corresponding products. In this study, the effect of the dynamic behavior of methoxy intermediate on methanol decomposition on a Pt/TiO(110) surface has been clarified by combination of scanning tunneling microscopy (STM), temperature-programmed desorption (TPD), and density functional theory (DFT) calculations.

Designing main-group catalysts for low-temperature methane combustion by ozone.

The catalytic combustion of methane at a low temperature is becoming increasingly key to controlling unburned CH emissions from natural gas vehicles and power plants, although the low activity of benchmark platinum-group-metal catalysts hinders its broad application. Based on automated reaction route mapping, we explore main-group elements catalysts containing Si and Al for low-temperature CH combustion with ozone. Computational screening of the active site predicts that strong Brønsted acid sites are promising for methane combustion.

Molybdenum Oxide Constructed by {MoO} Pentagonal Unit Assembly and Its Redox Properties.

Molybdenum oxides are widely used in various fields due to their electronic and structural characteristics. These materials can generate lattice oxygen defects by reduction treatments, which sometimes play central roles in various applications. However, little has been understood about their properties since it is difficult to increase the amount of lattice oxygen defects due to the crystal structure changes in most cases.

In- and Ga-oxo clusters/hydrides in zeolites: speciation and catalysis for light-alkane activations/transformations.

Metal-exchanged zeolites have great potential to form unique active metal species and develop their catalysis by promoting small molecules such as light alkanes. Ga-exchanged zeolites have attracted attention as promising heterogeneous catalysts for dehydrogenative light-alkane transformations. The speciation of active Ga species in reduced and oxidized Ga-exchanged zeolites and their reaction mechanisms have been discussed in several studies based on experimental and theoretical investigations.

An automated reaction route mapping for the reaction of NO and active species on Ag clusters in zeolites.

A computational investigation of the catalytic reaction on multinuclear sites is very challenging. Here, using an automated reaction route mapping method, the single-component artificial force induced reaction (SC-AFIR) algorithm, the catalytic reaction of NO and OH/OOH species over the Ag cluster in a zeolite is investigated. The results of the reaction route mapping for H + O reveal that OH and OOH species are formed over the Ag cluster an activation barrier lower than that of OH formation from HO dissociation.

Surface Engineering of Titania Boosts Electroassisted Propane Dehydrogenation at Low Temperature.

Electric field catalysis using surface proton conduction, in which proton hopping and collision on the reactant are promoted by external electricity, is a promising approach to break the thermodynamic equilibrium limitation in endothermic propane dehydrogenation (PDH). This study proposes a catalyst design concept for more efficient electroassisted PDH at low temperature. Sm was doped into the anatase TiO surface to increase surface proton density by charge compensation.

Continuous CO capture and methanation over Ni-Ca/AlO dual functional materials.

Although Ni-Ca-based dual functional materials (DFMs) have been examined for CO capture and reduction with H (CCR) for the synthesis of CH, their performance has generally been investigated using single reactors in an oxygen-free environment. In addition, continuous CCR operations have scarcely been investigated. In this study, continuous CCR for the production of CH was investigated using a double reactor system over AlO-supported Ni-Ca DFMs in the presence of O.

Interstitial Carbon Dopant in Palladium-Gold Alloy Boosting the Catalytic Performance in Vinyl Acetate Monomer Synthesis.

Vinyl acetate monomer (VAM), an important chemical intermediate in industry, is produced by the well-established commercial process of acetoxylation of ethylene with Pd-Au/SiO and a KOAc promoter. No paper has since decades defined the true effects of Au and KOAc, despite numerous attempts to clarify them. The role of subsurface carbon as a catalyst booster for enhanced catalytic performance in VAM synthesis was found by us for the first time.