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[Display omitted] • Mg incorporated into zeolite Beta framework by two-step postsynthesis procedure. • Rh3+/[MgO 4 ]2- electrostatic interactions stabilize single Rh atoms. • Catalytic efficiency of Rh/Mg-Beta due to low atomic coordination and basicity. • High selectivity in phenol hydrogenation to cyclohexanone at mild conditions. Nanoparticles are of interest in heterogeneous catalysis because of their excellent activity associated with atoms in a low coordination environment. However, their high reactivity becomes a drawback where selectivity is desired, compounded by their propensity towards agglomeration. Here, we show that stable subnanometric Rh particles can be prepared in a Mg-doped zeolite Beta based on the electrostatic interaction of the negatively charged zeolitic framework and the Rh3+ precursor. The Mg ions are incorporated into the zeolite framework whereas the Rh is located in the channels adjacent to the Mg. With only 0.27 and 0.5 wt% Mg and Rh, respectively, the Rh/Mg-Beta catalysts were highly active with > 94 % selectivity for the hydrogenation of phenol to cyclohexanone, an important intermediate for the production of Nylon. Key to the selectivity is the formation of the C=O double bond early in the reaction sequence, aided by the basicity of the Mg-Beta support. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zr-HY is an excellent catalyst for the cascade reaction. • Hydrophobicity and cosolvents significantly accelerate the title reaction. • Ratio of open:closed Zr sites higher in Zr-HY than Zr-Beta. • IR of sorbed 2-pentanol probes hydrophobic/hydrophilic environment. Trans -anethole is an important ingredient in many flavors, fragrances and pharmaceutical formulations. Heterogeneous catalysis provides the opportunity for its green synthesis from 4′-methoxypropiophenone via a cascade of Meerwein-Ponndorf-Verley reduction followed by dehydration. Zr-containing zeolites were especially active catalysts. Surprisingly, Zr-HY was more active than Zr-Beta or mesoporous Zr-MSU. The effect of pore size, hydrophobicity and co-solvent has been investigated. Pyridine poisoning revealed that weak Lewis acid sites can catalyze the MPV reduction but stronger acid sites are required for the dehydration. The hydrophobicity and the ratio of open/closed Zr sites were higher for Zr-HY than Zr-Beta. Adding a moderately polar co-solvent like p -xylene more than doubled the reaction rate compared to only 2-pentanol as solvent. For an efficient cascade reaction, a hydrophobic catalyst with large micropores is required which combines hydrogen transfer and dehydration activities, together with an inert co-solvent that balances the concentration of both substrates inside the zeolite. [ABSTRACT FROM AUTHOR]

• A highly efficient Cu/SiO 2 catalyst for non-oxidative dehydrogenation of ethanol. • Catalyst preparation by ammonia evaporation with optimum loading lends robustness. • High yields of acetaldehyde and hydrogen using 4.37% ethanol/Heat GHSV 8895 h−1. • Long catalyst lifetimewith minimal sintering and coking. While acetaldehyde is industrially produced in the Wacker process by homogeneous catalysts, a heterogeneous catalyst is so far elusive due to rapid deactivation stemming from metal sintering and coke formation. This work reports on a highly efficient, robust and stable Cu/SiO 2 catalyst for the non-oxidative dehydrogenation of ethanol prepared by the ammonia evaporation method. The highly dispersed Cu-particles are distinguished by outstanding thermal stability with very little sintering up to 600 °C. This was attributed to the strong interactions between the copper crystallites and SiO 2 arising from the intermediately formed copper phyllosilicate phase. Deactivation due to coke formation was successfully addressed by optimizing the metal loading. The CH x /Cu ratio in the used catalyst decreased by a factor of 10 as the copper loading was increased from 0.5 to 10 wt%. Samples with Cu ≥ 10 wt% demonstrated excellent activity of > 90% ethanol conversion and > 98% acetaldehyde selectivity with no observable deactivation for up to 500 h on-stream at 280 °C and a GHSV of 8895 h−1 (34,930 ml g-1h−1). [ABSTRACT FROM AUTHOR]

A silica-supported rhodium catalyst for the selective hydrogenation of phenol to cyclohexanone under mild conditions has been developed. As the Rh concentration on the catalyst increased from 0.5 to 15 wt%, the conversion (at phenol/Rh mole ratio 100/1) dropped whereas the initial selectivity to cyclohexanone increased. The direct hydrogenation to cyclohexanol occurred in parallel with partial hydrogenation to cyclohexanone. The negative correlation between selectivity and Rh dispersion suggests that direct hydrogenation occurs at low coordination sites whereas dissociation of phenol to phenoxy followed by hydrogenation to cyclohexanone takes place at higher coordinated terrace sites. DFT calculations revealed that the activation barrier for O–H bond cleavage is lower for phenol adsorbed on a Rh(1 1 1) flat surface than on small particles. By blocking the low coordination edge and step sites through grafting with (3-mercaptopropyl)trimethoxysilane, the cyclohexanone selectivity was improved from 82 to 93% at 100% conversion. The catalyst is active at room temperature and 1 atm H 2 pressure and can be easily activated by in-situ reduction. [ABSTRACT FROM AUTHOR]

[Display omitted] • A Co 3 O 4 -Bi 2 O 3 -Ti catalytic membrane was facilely fabricated. • The membrane efficiently activated PMS to degrade organic pollutants continuously. • Reactive oxidative species and non-radical electron transfer were involved. • The catalytic membrane showed excellent reusability. In this study, a functionalized Co 3 O 4 -Bi 2 O 3 -Ti catalytic membrane (CBO-Ti-M) was prepared and applied for removing organic pollutants via activating peroxymonosulfate (PMS) in the dead-end filtration mode. Characterizations including scanning electron microcopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) showed that the Co 3 O 4 -Bi 2 O 3 catalyst was successfully supported on the Ti membrane. The CBO-Ti-M /PMS system could efficiently remove various organic pollutants such as sulfamethoxazole, methyl orange, bisphenol A and methylene blue, achieving removal efficiencies of 98.0%-99.5%. The effects of PMS concentration, flow rate and solution environment on degradation efficiency were investigated in detail. Furthermore, quenching experiments, electron spin resonance (ESR) and in-situ open circuit potential (OCP) tests collectively demonstrated that singlet oxygen as well as the non-radical electron transfer pathway mainly contributed in the reaction mechanism. The synergistic effect of Co and Bi was illustrated according to XPS results, and the possible degradation pathway of MB was proposed based on LC-MS analysis. Reusability test showed that pollutant removal efficiency with the CBO-Ti-M /PMS system remained stable in four runs and limited metal leaching was observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrafine Pt-based intermetallic catalyst synthesized by in situ LRM strategy. • The electron-rich and isolated features of Pt sites in the Pt-based catalyst. • A superior catalytic performance for anti-Markovnikov alkene hydrosilylation. Regulating electronic structure of active centres to improve the performance of catalysts has always been a notable research topic, in which many challenges still need to be solved urgently. Herein, we report a PtFe 3 intermetallic catalyst anchored on N-doped carbon spheres (PtFe 3 /CN) with electron-rich isolated Pt active sites. The electron-rich nature of isolated Pt sites is attributed to the coordination of low electronegativity iron atoms. The PtFe 3 /CN catalyst showed a catalytic performance for the hydrosilylation of alkene superior to traditional single-atom Pt catalyst (coordinate with N etc. atoms) loading on N-doped graphene carbon (Pt1/CN) with electron-deficient isolated Pt sites and Pt nanoparticles supported N-doped carbon spheres (Pt NPs/CN) catalysts with the contiguous Pt sites. More importantly, turnover number (TON) of alkene hydrosilylation can reach a striking ca. 740,000 and no Pt leaching was detected. The opinion has been substantiated by both experimental and theoretical results that the PtFe 3 /CN catalyst can completely catalyze conversion of alkene and exhibit a high selectivity for anti-Markovnikov addition under environmentally friendly and mild conditions. [ABSTRACT FROM AUTHOR]