Supported IrO Nanocatalyst with Multilayered Structure for Proton Exchange Membrane Water Electrolysis.

The design of a low-iridium-loading anode catalyst layer with high activity and durability is a key challenge for a proton exchange membrane water electrolyzer (PEMWE). Here, the synthesis of a novel supported IrO nanocatalyst with a tri-layered structure, dubbed IrO@TaO@TaB that is composed of ultrasmall IrO nanoparticles anchored on amorphous TaO overlayer of TaB nanorods is reported. The composite electrocatalyst shows great activity and stability toward the oxygen evolution reaction (OER) in acid, thanks to its dual-interface structural feature.

Heteroatoms-Stabilized Single Palladium Atoms on Amorphous Zeolites: Breaking the Tradeoff between Catalytic Activity and Selectivity for Alkyne Semihydrogenation.

As a fundamental industrial catalytic process, the semihydrogenation of alkynes presents a challenge in striking a balance between activity and selectivity due to the issue of over-hydrogenation. Herein, we develop an efficient catalytic system based on single-atom Pd catalysts supported on boron-containing amorphous zeolites (Pd/AZ-B), achieving the tradeoff breaking between the activity and selectivity for the selective hydrogenation of alkynes. Advanced characterizations and theoretical density functional theory calculations confirm that the incorporated B atoms in the Pd/AZ-B can not only alter the geometric and electronic properties of Pd atoms by controlling the electron migration from Pd but also mitigate the interaction between alkene and the catalyst supports.

Nitrogen-doped carbon material NCM- heterogeneously catalyzed liquid-phase hydrogenation of nitrobenzene to aniline.

As an important chemical intermediate, aniline is primarily produced industrially through catalytic hydrogenation of nitrobenzene. Herein, a series of nitrogen-doped carbon materials (referred to as NCM-, with denoting the roasting temperature (°C)) were prepared through high-temperature roasting of sucrose and melamine for the heterogeneous catalytic liquid-phase hydrogenation of nitrobenzene to aniline. A preliminary study of the involved reaction mechanism was performed by combining the results of material characterisation and catalyst evaluation.

Optimizing Edge Active Sites via Intrinsic In-Plane Iridium Deficiency in Layered Iridium Oxides for Oxygen Evolution Electrocatalysis.

Improving catalytic activity of surface iridium sites without compromising catalytic stability is the core task of designing more efficient electrocatalysts for oxygen evolution reaction (OER) in acid. This work presents phase transition of a bulk layered iridate NaIrO in acid solution at room temperature, and subsequent exfoliation to produce 2D iridium oxide nanosheets with around 4 nm thickness. The nanosheets consist of OH-terminated, honeycomb-type layers of edge-sharing IrO octahedral framework with intrinsic in-plane iridium deficiency.

Encapsulation of Palladium Carbide Subnanometric Species in Zeolite Boosts Highly Selective Semihydrogenation of Alkynes.

The selective hydrogenation of alkynes to alkenes is a crucial step in the synthesis of fine chemicals. However, the widely utilized palladium (Pd)-based catalysts often suffer from poor selectivity. In this work, we demonstrate a carbonization-reduction method to create palladium carbide subnanometric species within pure silicate MFI zeolite.

Electrocatalytic Water Oxidation Activity-Stability Maps for Perovskite Oxides Containing 3d, 4d and 5d Transition Metals.

Improving catalytic activity without loss of catalytic stability is one of the core goals in search of low-iridium-content oxygen evolution electrocatalysts under acidic conditions. Here, we synthesize a family of 66 SrBO perovskite oxides (B=Ti, Ru, Ir) with different Ti : Ru : Ir atomic ratios and construct catalytic activity-stability maps over composition variation. The maps classify the multicomponent perovskites into chemical groups with distinct catalytic activity and stability for acidic oxygen evolution reaction, and highlights a chemical region where high catalytic activity and stability are achieved simultaneously at a relatively low iridium level.

Nano-metal diborides-supported anode catalyst with strongly coupled TaO/IrO catalytic layer for low-iridium-loading proton exchange membrane electrolyzer.

The sluggish kinetics of oxygen evolution reaction (OER) and high iridium loading in catalyst coated membrane (CCM) are the key challenges for practical proton exchange membrane water electrolyzer (PEMWE). Herein, we demonstrate high-surface-area nano-metal diborides as promising supports of iridium-based OER nanocatalysts for realizing efficient, low-iridium-loading PEMWE. Nano-metal diborides are prepared by a novel disulphide-to-diboride transition route, in which the entropy contribution to the Gibbs free energy by generation of gaseous sulfur-containing products plays a crucial role.

Polymorphic Covalent Organic Frameworks: Molecularly Defined Pore Structures and Iodine Adsorption Property.

Radioactive iodine-capturing materials are urgently needed for the emerging challenges in nuclear waste disposal. The various pore structures of covalent organic frameworks (COFs) render them promising candidates for efficient iodine adsorption. However, the detailed structure-property relationship of COFs in iodine adsorption remains elusive.

A Highly Active, Long-Lived Oxygen Evolution Electrocatalyst Derived from Open-Framework Iridates.

The acidic oxygen evolution reaction underpins several important electrical-to-chemical energy conversions, and this energy-intensive process relies industrially on iridium-based electrocatalysts. Here, phase-selective synthesis of metastable strontium iridates with open-framework structure and their unexpected transformation into a highly active, ultrastable oxygen evolution nano-electrocatalyst are presented. This transformation involves two major steps: Sr /H ion exchange in acid and in situ structural rearrangement under electrocatalysis conditions.

Switching between classical/nonclassical crystallization pathways of TS-1 zeolite: implication on titanium distribution and catalysis.

In the MFI zeolite crystallization process, the classical crystallization mechanism based upon the addition of silica species is often concomitant with the nonclassical route that is characteristic of the attachment of silica nanoparticle precursors. However, the factors that govern the preferences for each mechanism remain unclear. In this work, we present the impact of switching between these two crystallization pathways on the active sites and the resulting catalytic performance of the titanosilicate TS-1 zeolite.

Exsolution of Iron Oxide on LaFeO Perovskite: A Robust Heterostructured Support for Constructing Self-Adjustable Pt-Based Room-Temperature CO Oxidation Catalysts.

Constructing highly active and stable surface sites for O activation is essential to lower the barrier of Pt-based catalysts for CO oxidation. Although a few active Pt-metal oxide interfaces have been reported, questions about the stability of these sites under the long-term storage and operation remain unresolved. Here, based on developing a robust FeO/LaFeO heterostructure as a support, we constructed stable Pt-support interfaces to achieve highly active CO oxidation at room temperature.

Titanosilicate zeolite precursors for highly efficient oxidation reactions.

Titanosilicate zeolites are catalysts of interest in the field of fine chemicals. However, the generation and accessibility of active sites in titanosilicate materials for catalyzing reactions with large molecules is still a challenge. Herein, we prepared titanosilicate zeolite precursors with open zeolitic structures, tunable pore sizes, and controllable Si/Ti ratios through a hydrothermal crystallization strategy by using quaternary ammonium templates.

Electron donation of non-oxide supports boosts O activation on nano-platinum catalysts.

Activation of O is a critical step in heterogeneous catalytic oxidation. Here, the concept of increased electron donors induced by nitrogen vacancy is adopted to propose an efficient strategy to develop highly active and stable catalysts for molecular O activation. Carbon nitride with nitrogen vacancies is prepared to serve as a support as well as electron sink to construct a synergistic catalyst with Pt nanoparticles.

Macrocyclic Arenes-Based Conjugated Macrocycle Polymers for Highly Selective CO Capture and Iodine Adsorption.

Incorporating synthetic macrocycles with unique structures and distinct conformations into conjugated macrocycle polymers (CMPs) can endow the resulting materials with great potentials in gas uptake and pollutant adsorption. Here, four CMPs (CMP-n, n=1-4) capable of reversibly capturing iodine and efficiently separating carbon dioxide are constructed from per-triflate functionalized leaning tower[6]arene (LT6-OTf) and [2]biphenyl-extended pillar[6]arene (BpP6-OTf) via Pd-catalyzed Sonogashira-Hagihara cross-coupling reaction. Intriguingly, owing to the appropriate cavity size of LT6-OTf and the numerous aromatic rings in the framework, the newly designed CMP-4 possesses an outstanding I affinity with a large uptake capacity of 208 wt % in vapor and a great removal efficiency of 94 % in aqueous solutions.

Construction of fluorescence active MOFs with symmetrical and conformationally rigid -2-aryl-triazole ligands.

1,4-Bis-triazole-substituted arene (NAT) was designed and synthesized for the construction of metal organic frameworks. Unlike the tri-phenyl analogs, which give a twisted conformation between three benzene rings due to the A-1,3 repulsion, the NAT-ligand gave the energetically favored co-planar conformation with the strong fluorescence emission. With this ligand, two new MOFs, NAT-MOF-Cd (2,3,4-c) and NAT-MOF-Cu (4-c), were successfully obtained with the structure confirmed by X-ray.

Polyoxometalate-viologen photochromic hybrids for rapid solar ultraviolet light detection, photoluminescence-based UV probing and inkless and erasable printing.

In this work, a new crystalline polyoxometalate-viologen hybrid, (Pbpy)(MeNH)[PWZnO] (1: Pbpy = 1,1'-[1,4-phenylenebis-(methylene)]bis(4,4'-bipyridinium)), has been synthesized. It showed efficient ultraviolet light detection ability with an obvious colour change from pale yellow to blue and fast response with ultraviolet intensity as low as 0.006 mW cm in narrow-band UV regions.

Mesoporogen-Free Synthesis of Hierarchical SAPO-34 with Low Template Consumption and Excellent Methanol-to-Olefin Conversion.

Significant interest has emerged in the development of nanometer-sized and hierarchical silicoaluminophosphate zeolites (SAPO-34) because of their enhanced accessibility and improved catalytic activity for methanol-to-olefin (MTO) conversion. A series of nanometer-sized SAPO-34 catalysts with tunable hierarchical structures was synthesized in a Al O /H PO /SiO /triethylamine(TEA)/H O system by using a mesoporogen-free nanoseed-assisted method. The nanometer-sized hierarchical S -3.

Development of novel magnetic solid phase extraction materials based on Fe3O4/SiO2/poly(acrylamide-N,N'-methylene bisacrylamide)-Pluronic L64 composite microspheres and their application to the enrichment of natamycin.

Novel magnetic adsorbents based on Fe3O4/SiO2/poly(acrylamide-N,N'-methylene bisacrylamide) magnetic microspheres modified with non-ionic triblock copolymer surfactant were successfully prepared as a magnetic solid phase extraction adsorbent for the determination of trace natamycin in jam samples. The adsorbent was characterized by scanning electron microscopy, transmission electron microscopy, Fourier transformed infrared spectroscopy, vibrating sample magnetometer, and X-ray diffractometer analysis, confirming that Pluronic L64 was effectively functionalized on the magnetic materials. Various experimental parameters affecting the extraction capacity were investigated including adsorbent amount, extraction time, desorption time, sample pH, and ionic strength.

An Azine-Linked Covalent Organic Framework: Synthesis, Characterization and Efficient Gas Storage.

A azine-linked covalent organic framework, COF-JLU2, was designed and synthesized by condensation of hydrazine hydrate and 1,3,5-triformylphloroglucinol under solvothermal conditions for the first time. The new covalent organic framework material combines permanent micropores, high crystallinity, good thermal and chemical stability, and abundant heteroatom activated sites in the skeleton. COF-JLU2 possesses a moderate BET surface area of over 410 m(2)  g(-1) with a pore volume of 0.

Carbon-armored Co9S8 nanoparticles as all-pH efficient and durable H2-evolving electrocatalysts.

Splitting water to produce hydrogen requires the development of non-noble-metal catalysts that are able to make this reaction feasible and energy efficient. Herein, we show that cobalt pentlandite (Co9S8) nanoparticles can serve as an electrochemically active, noble-metal-free material toward hydrogen evolution reaction, and they work stably in neutral solution (pH 7) but not in acidic (pH 0) and basic (pH 14) media. We, therefore, further present a carbon-armoring strategy to increase the durability and activity of Co9S8 over a wider pH range.

A 2D azine-linked covalent organic framework for gas storage applications.

A new azine-linked covalent organic framework, ACOF-1, was synthesized by condensation of hydrazine hydrate and 1,3,5-triformylbenzene under solvothermal conditions. ACOF-1 has a high surface area and a small pore size, and it can store up to 177 mg g(-1) of CO2, 9.9 mg g(-1) of H2, and 11.

Self-template construction of hollow Co3O4 microspheres from porous ultrathin nanosheets and efficient noble metal-free water oxidation catalysts.

Developing noble metal-free water oxidation catalysts is essential for many energy conversion/storage processes (e.g., water splitting).

Correlation between the microstructures of graphite oxides and their catalytic behaviors in air oxidation of benzyl alcohol.

A series of graphite oxide (GO) materials were obtained by thermal treatment of oxidized natural graphite powder at different temperatures (from 100 to 200 °C). The microstructure evolution (i.e.

A general route to hollow mesoporous rare-earth silicate nanospheres as a catalyst support.

Hollow mesoporous structures have recently aroused intense research interest owing to their unique structural features. Herein, an effective and precisely controlled synthesis of hollow rare-earth silicate spheres with mesoporous shells is reported for the first time, produced by a simple hydrothermal method, using silica spheres as the silica precursors. The as-prepared hollow rare-earth silicate spheres have large specific surface area, high pore volume, and controllable structure parameters.