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Photocatalysis provides an eco-friendly route for the hydrogenation of aromatic carbonyls to O-free aromatics, which is an important refining process in the chemical industry that is generally carried out under high pressure of hydrogen at elevated temperatures. However, aromatic carbonyls are often only partially hydrogenated to alcohols, which readily desorbs and are hardly further deoxygenated under ambient conditions. Here, we show that by constructing an oxide surface over the Pd cocatalyst supported on graphitic carbon nitride, an alternative hydrogenation path of aromatic carbonyls becomes available via a step-wise acetalization and hydrogenation, thus allowing efficient and selective production of O-free aromatics. The PdO surface allows for optimum adsorption of reactants and intermediates and rapid abstraction of hydrogen from the alcohol donor, favoring fast acetalization of the carbonyls and their consecutive hydrogenation to O-free hydrocarbons. The photocatalytic hydrogenation of benzaldehyde into toluene shows a high selectivity of >90% and a quantum efficiency of ∼10.2% under 410 nm irradiation. By adding trace amounts of HCl to the reaction solution, the PdO surface remains stable and active for long-term operation at high concentrations, offering perspective for practical applications.

The matching degree between the zeolite channel size and the isomer size determines the product distribution of dodecane hydroisomerization.

The synergistic effect of Pt in different electronic states induces Sn-modified Pt/KY catalyst with high aromatization ability in n-octane reforming.

Environmental-friendly halogenation of C−H bonds using abundant, non-toxic halogen salts is in high demand in various chemical industries, yet the efficiency and selectivity of laboratory available protocols are far behind the conventional photolytic halogenation process which uses hazardous halogen sources. Here we report an FeX2 (X=Br, Cl) coupled semiconductor system for efficient, selective, and continuous photocatalytic halogenation using NaX as halogen source under mild conditions. Herein, FeX2 catalyzes the reduction of molecular oxygen and the consumption of generated oxygen radicals, thus boosting the generation of halogen radicals and elemental halogen for direct halogenation and indirect halogenation via the formation of FeX3. Recycling of FeX2 and FeX3 during the photocatalytic process enables the halogenation of a wide range of hydrocarbons in a continuous flow, rendering it a promising method for applications.

Heterogeneous photocatalysis is effective for the selective synthesis of value-added chemicals at lab-scale, yet falls short of requirements for mass production (low cost and user friendliness). Here we report the design and fabrication of a modular tubular flow system embedded with replaceable photocatalyst membranes for scalable photocatalytic C−C, C−N homocoupling and hydrogenation reactions, which can be operated in either circular and continuous flow mode with high performance. The photocatalyst membranes almost fully occupy the volume of the reactor, thus enabling optimal absorption of the incident light. Additionally, the porous structured photocatalyst membranes facilitate the mass transfer of the reactants to efficiently use the active sites, resulting in 0th-order reaction kinetics and a high space-time yield compared to the batch reaction system at practical application levels and prolonged reaction times.

The adsorption and dissociation of O2on Ir(100) has been studied with X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED) and scanning tunneling microscopy together with density functional theory calculations. At low coverage, XPS shows a single O 1s peak at 530.6 eV, associated with bridged O atoms in an Ir(100)-(3 × 1)-O structure. At saturation coverage, an additional peak at 529.5 eV appears, accompanied by an Ir(100)-(2 × 1)-O structure. The O 1s peak at 530.6 eV is assigned to oxygen atoms adsorbed on bridge sites of Ir atoms, and the peak at 529.5 eV to oxygen atoms on fourfold hollow sites of Ir. Based on our detailed experimental and computational study, oxygen diffusion into the subsurface region can be ruled out. The present study provides new findings on an additional oxygen state of the O/Ir(100) system. It also provides evidence for the absence of subsurface oxygen in Ir, implying that some discussions on subsurface oxygen in the literature may be misleading.

Polyethylene production through catalytic ethylene polymerization is one of the most common processes in the chemical industry. The popular Cossee-Arlman mechanism hypothesizes that the ethylene be directly inserted into the metal–carbon bond during chain growth, which has been awaiting microscopic and spatiotemporal experimental confirmation. Here, we report an in situ visualization of ethylene polymerization by scanning tunneling microscopy on a carburized iron single-crystal surface. We observed that ethylene polymerization proceeds on a specific triangular iron site at the boundary between two carbide domains. Without an activator, an intermediate, attributed to surface-anchored ethylidene (CHCH 3 ), serves as the chain initiator (self-initiation), which subsequently grows by ethylene insertion. Our finding provides direct experimental evidence of the ethylene polymerization pathway at the molecular level.

The first-order phase transition plays a pivotal role in material behaviors, yet that of carbides, a type of important materials, has not been systematically studied. Herein, the melting process and structural properties of binary iron carbide (FexCy) nanoparticles are characterized by reactive molecular dynamics simulation. It was found that the melting point of FexCy nanoparticle decreased with decreasing size and increased with increasing Fe/C ratio, which were consistent with the experimental results. The melting process starts at the surface and proceeds inwards. The carbon atoms are fully activated before reaching the melting point and the iron core melts last. At high temperatures, carbon atoms exhibit significant outward diffusion behavior and form carbon deposition on the surface. When the temperature exceeds the pre-melting point, although the high temperature gives the nanoparticles more atomic active sites with low coordination, the surface carbon accumulation, such as C2, blocks the active sites leading to a lower turn-over frequency of FexCy for CO dissociation. These findings provide an atomistic comprehension of the melting mechanisms and behaviors of binary FexCy nanoparticles, as well as a theoretical foundation for understanding their structural transformation as a catalyst, which is caused by the heat released from catalytic exothermic reactions.

A moderate adsorption of benzyl halogens and appropriate kinetics of reaction intermediates are the keys to achieve efficient C–C coupling on the Ni/gCN photocatalyst.

The weakened catalytic role of the zeolite channels might be a considerable reason for the low superiority of Pt/KL catalysts in n-octane aromatization.

In situ generated Cu dendrites stabilize the NiFe(OH)x electrocatalyst for HER of over 1000 h in alkaline electrolyte.

An alcoholysis-hydrogenation integrated continuous process for the production of 1,4-PDO from industrialized FOL.

Fischer-Tropsch synthesis (FTS) wax is a mixture of linear hydrocarbons with carbon number from C7 to C70+. Converting FTS wax into high-quality diesel (no sulfur and nitrogen contents) by hydrocracking technology is attractive in economy and practicability. Kinetic study of the hydrocracking of FTS wax in elementary step level is very challenging because of the huge amounts of reactions and species involved. Generation of reaction networks for hydrocracking of FTS wax in which the chain length goes up to C70 is described on the basis of Boolean adjacency matrixes. Each of the species (including paraffins, olefins and carbenium ions) involved in the elementary steps is represented digitally by using a (N+3)×N matrix, in which a group of standardized numbering rules are designed to guarantee the unique identity of the species. Subsequently, the elementary steps are expressed by computer-aided matrix transformations in terms of proposed reaction rules. Dynamic memory allocation is used in species storage and a characteristic vector with nine elements is designed to store the key information of a (N+3)×N matrix, which obviously reduces computer memory consumption and improves computing efficiency. The detailed reaction networks of FTS wax hydrocracking can be generated smoothly and accurately by the current method. The work is the basis of advanced elementary-step-level kinetic modeling.

H-Beta zeolites were employed for hexose decarburization to furfural. Excellent performance was achieved over high-Si H-Beta zeolite due to its high B/(B + L) ratio. The synergetic mechanism between *BEA channel and framework-Al is decisive.

The lower the minimum surface electrostatic potential of the ligand, the better the modification effect on Ru-based catalysts. The modification effect of HMTA and DABCO on Ru-based catalysts is greatly improved when they are prepared into organic chlorine salts.

The shape engineering of semiconductor photocatalysts has been frequently employed to improve the charge separation and thus the photocatalytic performance of hydrogen evolution and CO2 reduction, ...

The intrinsic principle of the electronic property of Pt catalysts for the selective hydrogenation of 1,3-butadiene was systemically elucidated.

Pincer ligand supported RuII chloride complexes may be used for acetylene hydrochlorination as non-mercury molecular catalysts. Based on theoretical calculations, the catalytic mechanism and the interaction between catalysts and reactants has been evaluated, indicating that the (pincer)RuIICl2 platform supports electrophilic proton-ruthenation of C2H2. Energy decomposition studies further illustrate the electron-rich property of the RuII center, which can increase the negative charge of C2H2 via 4d-electron backdonation. Thus, the electrophilic reaction mechanism is favored due to lower energetic barriers. By improving the electron-donating ability of ligands, this lowering of energetic barriers can be enhanced. Therefore, non-mercury catalysts for acetylene hydrochlorination with milder reaction conditions and higher catalytic activity can be designed.

Multimetallic nanoparticles are an important class of catalysts with significant technological potential. In this work, trimetallic PtPdCu nanoparticles synthesized via a facile one-pot colloidal m...

Developing phosphors with narrow band emission and excellent performance is the main goal of current leading research. In this study, a novel narrow band blue-emitting phosphor Rb2ZrSi3O9: Eu2+ was prepared that can be fully excited by near ultraviolet (NUV) light, emits a bright blue light peak at 470 nm, and has a full width at half maximum (FWHM) of 60 nm. The synthesized Rb2ZrSi3O9: Eu2+ had excellent photoluminescence properties that were reflected in its good thermal stability (up to 82%) and high internal quantum efficiency (up to 75%). These remarkable luminescence properties were mainly ascribed to the highly symmetric and dense crystal structure composed of [Si3O9]6- ring pairs. Multiple emission centers in the Rb2ZrSi3O9: Eu2+ phosphor were confirmed through the photoluminescence (PL) spectra and time-resolved (PL) spectra. A bright warm WLED device with a low correlated color temperature (3386 K) and high color-rendering index (CRI~89.3) was produced by combining the blue phosphor with (Sr, Ba)2SiO4: Eu2+ and CaAlSiN3: Eu2+ and NUV (380 nm). The results indicate that Rb2ZrSi3O9: Eu2+ could be a promising phosphor for use in WLEDs.

Cobalt carbides nanoparticles have great potential as novel materials in magnetic fields. However, it is difficult to synthesize single phase cobalt carbides, especially Co3C. In this paper, we propose a one‐pot wet‐chemistry approach to synthesize single phase ferromagnetic Co3C without using any alkali as nucleation solvent. The particle size of Co3C nanoparticle is about 3 nm. The magnetic properties of Co3C nanoparticles are measured at 300 K from –30 to 30 kOe. Compared with Co2C, Co3C exhibits a large saturation magnetization of 46.1 emu g–1 and a high coercivity of 1.5 kOe. Small amount of carbon and small particle size of the Co3C nanoparticle are believed to contribute to large magnetization and high coercivity. Magnetic measurements also reveal the spin glass behavior caused by the small Co3C nanoparticle at the spin freezing temperature of 43 K. This work provides a facile method to synthesize single phase Co3C nanoparticle which is applicable in magnetic field.

Keeping water away Syngas, a mixture of carbon monoxide (CO) and hydrogen, allows nonpetroleum resources such as biomass and natural gas to be converted to chemical products through Fischer-Tropsch synthesis. However, for the production of olefins, a key feedstock for other chemicals, about 50% of the CO is transformed to carbon dioxide and methane. Xu et al. decreased the selectivity for these undesired by-products to under 25% by modifying their catalyst, nanoparticles of iron doped with manganese and coated with a silica, with methyl groups (see the Perspective by Xie). This hydrophobic surface shortens the retention time of water on the catalyst surface to avoid the unwanted side reactions, and also suppresses oxidation of the metal carbide catalyst that forms under reaction conditions. Science , this issue p. 610 ; see also p. 577