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Replacement of Hg with non-toxic Au based catalysts for industrial hydrochlorination of acetylene to vinyl chloride is urgently required. However Au catalysts suffer from progressive deactivation caused by auto-reduction of Au(I) and Au(III) active sites and irreversible aggregation of Au(0) inactive sites. Here we show from synchrotron X-ray absorption, STEM imaging and DFT modelling that the availability of ceria(110) surface renders Au(0)/Au(I) as active pairs. Thus, Au(0) is directly involved in the catalysis. Owing to the strong mediating properties of Ce(IV)/Ce(III) with one electron complementary redox coupling reactions, the ceria promotion to Au catalysts gives enhanced activity and stability. Total pre-reduction of Au species to inactive Au nanoparticles of Au/CeO 2 &AC when placed in a C 2 H 2 /HCl stream can also rapidly rejuvenate. This is dramatically achieved by re-dispersing the Au particles to Au(0) atoms and oxidising to Au(I) entities, whereas Au/AC does not recover from the deactivation.

Three morphology-controlled CeO₂, namely nanorods (NRs), nanocubes (NCs), and nanopolyhedra (NPs), with different mainly exposed crystal facets of (110), (100), and (111), respectively, have been used as supports to prepare Ru (3 wt.%) nanoparticle-loaded catalysts. The catalysts were characterized by H₂-temperature programmed reduction (H₂-TPR), CO⁻ temperature programmed desorption (CO-TPD), N₂ adsorption⁻desorption, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectroscopy (XDS). The characterization results showed that CeO₂-NRs, CeO₂-NCs, and CeO₂-NPs mainly expose (110), (100) and (111) facets, respectively. Moreover, CeO₂-NRs and CeO₂-NCs present higher oxygen vacancy concentration than CeO₂-NPs. In the CO₂ reforming of methane reaction, Ru/CeO₂-NR and Ru/CeO₂-NC catalysts showed better catalytic performance than Ru/CeO₂-NPs, indicating that the catalysts with high oxygen vacancy concentration are beneficial for promoting catalytic activity.

γ-Valerolactone (GVL) is regarded as a key platform molecule in the production of fine chemicals such as pentenoic acid (PA) from biomass. Although PA is believed to be the key intermediate in solid-acid-catalyzed reactions of GVL, due to subsequent facile decarboxylation reactions further alkene products are formed. Here, by tailoring the acidity of Brønsted acid sites in an aluminophosphate (AlPO) molecular sieve through incorporation of Zn 2+ into the framework, we access a new selective and effective catalyst for GVL conversion to PA., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The acidity enhancement induced by the nonpolar solvent effect of naphthalene inside zeolites was unambiguously identified. The mechanism of such an effect due to the CH/π interaction in the nonpolar environment has been revealed based on the advanced 2D 1H-13C correlation NMR technique and DFT calculations for the first time.

The use of sunlight to drive chemical reactions via photocatalysis is of paramount importance towards a sustainable future. Among several photocatalysts, earth-abundant polymeric carbon nitride (PCN, often wrongly named g-C3N4) has emerged as an attractive candidate due to its ability to absorb light efficiently in the visible and near-infrared ranges, chemical stability, non-toxicity, straightforward synthesis, and versatility as a platform for constructing hybrid materials. Especially, hybrids with metal nanoparticles offer the unique possibility of combining the catalytic, electronic, and optical properties of metal nanoparticles with PCN. Here, we provide a comprehensive overview of PCN materials and their hybrids, emphasizing heterostructures with metal nanoparticles. We focus on recent advances encompassing synthetic strategies, design principles, photocatalytic applications, and charge-transfer mechanisms. We also discuss how the localized surface plasmon resonance (LSPR) effect of some noble metals NPs (e.g. Au, Ag, and Cu), bimetallic compositions, and even non-noble metals NPs (e.g., Bi) synergistically contribute with PCN in light-driven transformations. Finally, we provide a perspective on the field, in which the understanding of the enhancement mechanisms combined with truly controlled synthesis can act as a powerful tool to the establishment of the design principles needed to take the field of photocatalysis with PCN to a new level, where the desired properties and performances can be planned in advance, and the target material synthesized accordingly.

Foreign transition metals are doped into the hexagonal nickel phosphide structure through a simple and facile bottom-up wet-chemical synthesis process via stabilization with oleylamine, trioctylphosphine (TOP), and trioctylphosphine oxide (TOPO): the as-prepared transition metal-doped nickel phosphide nanoparticles show a high level of doping but create no significant distortion of the crystal structure and morphology against pristine nickel phosphide nanoparticles, which exhibit excellent activity in the electrochemical oxygen evolution reaction (OER), having overpotential as small as 330 mV at 20 mA cm -2 with a low Tafel slope value of 39 mV dec -1 .

The traditional investigation of complex catalyst poisoning phenomena is in the operation level: poisonings commonly attributed to macroscopic coke deposition and particle size change, etc. Here, we demonstrate that high-resolution SXRD can reveal the structure of the organic molecule-active site complex in a 3-D environment, leading to an understanding of the poisoning mechanism at the molecular level.

Surface sites of extensively exposed basal planes of MoS 2 monolayer nanosheets, prepared via BuLi exfoliation of MoS 2 , have been doped with transition metal atoms for the first time to produce 2D monolayer catalysts used for the electrochemical hydrogen evolution reaction (HER). Their HER activity is significantly higher than the corresponding thin and bulk MoS 2 layers. HAADF-STEM images show direct proof that single transition metal atoms reside at the surface basal sites, which subtly modify the electro-catalytic activity of the monolayer MoS 2 , dependent on their electronic and stereospecific properties. It is found that these dopants play an important role in tuning the hydrogen adsorption enthalpies of the exposed surface S atoms and Mo atoms in HER. We report electrochemical testing, characterization and computational modelling and demonstrate that Co can significantly enhance the HER activity by the dominant Co-S interaction, whereas Ni substantially lowers the HER rate due to the Ni-Mo interaction at the same basal site. The two transition metal dopants show opposite doping behavior despite the fact that they are neighbors in the periodic table.

Tagging recognition group(s) on superparamagnetic iron oxide is known to aid localisation (imaging), stimulation and separation of biological entities using magnetic resonance imaging (MRI) and magnetic agitation/separation (MAS) techniques. Despite the wide applicability of iron oxide nanoparticles in T 2 -weighted MRI and MAS, the quality of the images and safe manipulation of the exceptionally delicate neural cells in a live brain are currently the key challenges. Here, we demonstrate the engineered manganese oxide clusters-iron oxide core-shell nanoparticle as an MR dual-modal contrast agent for neural stem cells (NSCs) imaging and magnetic manipulation in live rodents. As a result, using this engineered nanoparticle and associated technologies, identification, stimulation and transportation of labelled potentially multipotent NSCs from a specific location of a live brain to another by magnetic means for self-healing therapy can therefore be made possible.

The use of surface-directing species and surface additives to alter nanoparticle morphology and physicochemical properties of particular exposed facets has recently been attracting significant attention. However, challenges in their chemical analysis, sometimes at trace levels, and understanding their roles to elucidate surface structure-activity relationships in optical (solar cells) or (photo)catalytic performance and their removal are significant issues that remain to be solved. Here, we show a detailed analysis of TiO 2 facets promoted with surface species (OH, O, SO 4 , F) with and without post-treatments by 31 P adsorbate nuclear magnetic resonance, supported by a range of other characterization tools. We demonstrate that quantitative evaluations of the electronic and structural effects imposed by these surface additives and their removal mechanisms can be obtained, which may lead to the rational control of active TiO 2 (001) and (101) facets for a range of applications.Metal oxide nanocrystals can be grown with different facets exposed to give variations in reactivity, but the chemical state of these surfaces is not clear. Here, the authors make use of a phosphine probe molecule allowing the differences in surface chemistry to be mapped by NMR spectroscopy.

Bio-oil, produced by the destructive distillation of cheap and renewable lignocellulosic biomass, contains high energy density oligomers in the water-insoluble fraction that can be utilized for diesel and valuable fine chemicals productions. Here, we show an efficient hydrodeoxygenation catalyst that combines highly dispersed palladium and ultrafine molybdenum phosphate nanoparticles on silica. Using phenol as a model substrate this catalyst is 100% effective and 97.5% selective for hydrodeoxygenation to cyclohexane under mild conditions in a batch reaction; this catalyst also demonstrates regeneration ability in long-term continuous flow tests. Detailed investigations into the nature of the catalyst show that it combines hydrogenation activity of Pd and high density of both Brønsted and Lewis acid sites; we believe these are key features for efficient catalytic hydrodeoxygenation behavior. Using a wood and bark-derived feedstock, this catalyst performs hydrodeoxygenation of lignin, cellulose, and hemicellulose-derived oligomers into liquid alkanes with high efficiency and yield.Bio-oil is a potential major source of renewable fuels and chemicals. Here, the authors report a palladium-molybdenum mixed catalyst for the selective hydrodeoxygenation of water-insoluble bio-oil to mixtures of alkanes with high carbon yield.

Hydrated niobium oxides are used as strong solid acids with a wide variety of catalytic applications, yet the correlations between structure and acidity remain unclear. New insights into the structural features giving rise to Lewis and Brønsted acid sites are presently achieved. It appears that Lewis acid sites can arise from lower coordinate NbO 5 and in some cases NbO 4 sites, which are due to the formation of oxygen vacancies in thin and flexible NbO 6 systems. Such structural flexibility of Nb-O systems is particularly pronounced in high surface area nanostructured materials, including few-layer to monolayer or mesoporous Nb 2 O 5 ·nH 2 O synthesized in the presence of stabilizers. Bulk materials on the other hand only possess a few acid sites due to lower surface areas and structural rigidity: small numbers of Brønsted acid sites on HNb 3 O 8 arise from a protonic structure due to the water content, whereas no acid sites are detected for anhydrous crystalline H-Nb 2 O 5 .

Herein, we report the catalytic decarboxylation of γ-valerolactone (GVL) over Zn/ZSM-5 to butene, followed by aromatization at high yield with co-feeding of water. An evaluation of the catalytic performance after prolonged periods of time showed that a water molecule is essential to maintain the decarboxylation and aromatization activities and avoid rapid catalyst deactivation. Synchrotron X-ray powder diffraction and Rietveld refinement were then used to elucidate the structures of adsorbed GVL and immobilized Zn species in combination with EXAFS and NMR spectroscopy. A new route for the cooperative hydrolysis of GVL by framework Zn-OH and Brønsted acidic sites to butene and then to aromatic compounds has thus been demonstrated. The structures and fundamental pathways for the nucleophilic attack of terminal Zn-OH sites are comparable to those of Zn-containing enzymes in biological systems., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The conversion of oxygen-rich biomass into hydrocarbon fuels requires efficient hydrodeoxygenation catalysts during the upgrading process. However, traditionally prepared CoMoS 2 catalysts, although efficient for hydrodesulfurization, are not appropriate due to their poor activity, sulfur loss and rapid deactivation at elevated temperature. Here, we report the synthesis of MoS 2 monolayer sheets decorated with isolated Co atoms that bond covalently to sulfur vacancies on the basal planes that, when compared with conventionally prepared samples, exhibit superior activity, selectivity and stability for the hydrodeoxygenation of 4-methylphenol to toluene. This higher activity allows the reaction temperature to be reduced from the typically used 300 °C to 180 °C and thus allows the catalysis to proceed without sulfur loss and deactivation. Experimental analysis and density functional theory calculations reveal a large number of sites at the interface between the Co and Mo atoms on the MoS 2 basal surface and we ascribe the higher activity to the presence of sulfur vacancies that are created local to the observed Co-S-Mo interfacial sites.

Niobate nanosheets are assembled into thin membranes by a vacuum filtration. The nanosheet membranes have a dense and stable structure in water via chemical cross-linking and show higher permeance and salt rejection compared with graphene oxide membranes. A water pathway model based on the void structure is presented to explain the membrane performances.

Using physical mixtures of Pd/SWNTs (Pd nanoparticles on single-walled carbon nanotubes) and Pt/SWNTs, the composites show electro-catalytic properties comparable to the corresponding alloys: electron exchange readily occurs between the two metal nanoparticles via SWNT support at long ranges without direct atomic contact, which is responsible for the tunable alloy-like properties.