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Alkene hydroformylation with syngas (CO + H 2 ) to produce aldehydes is one of the most important chemical reactions. However, designing heterogeneous catalysts to realize comparable performance with mature homogeneous catalysts is challenging. In this report, a reduced graphene oxide (RGO) supported rhodium nanoparticle (Rh/RGO) catalyst was successfully prepared via a one-pot liquid-phase reduction method and first applied in 1-hexene hydroformylation. 1-Hexene hydroformylation reaction under different reaction conditions with this Rh/RGO catalyst was investigated in detail. Low reaction temperature and short reaction time effectively enhanced the n / i (normal to iso) ratio of heptanal in the products. The catalytic performance of the Rh/RGO catalyst was also compared with those of Rh supported on other carbon materials, including activated carbon and carbon nanotubes (Rh/AC and Rh/CNTs). The results showed that the Rh/RGO catalyst exhibited the highest 1-hexene conversion and the largest n / i ratio of 4.0 among the tested catalysts. The special 2D nanosheet structure of the Rh/RGO catalyst, rather than the 3D porous and 1D nanotube structures of Rh/AC and Rh/CNTs, respectively, principally contributed to its excellent catalytic performance. These findings disclosed that reduced graphene oxide could be a promising catalyst support for designing heterogeneous hydroformylation catalysts.

The first page of this article is displayed as the abstract.

In the present study, the zinc-catalysed reduction of a variety of sulfoxides with silanes as reductant to the corresponding sulfide has been examined in detail. With the straightforward and commercially available zinc( II ) triflate as pre- catalyst , excellent yields and chemoselectivities were feasible. After studying the reaction conditions and the scope and limitations several attempts were undertaken to shed light on the reaction mechanism.

Magnetite samples were synthesized and studied as the cycling material of a chemical loop process for hydrogen production from ethanol and water used as reducing and oxidizing species, respectively. Surface and structural changes during the process were characterized by various techniques such as X-ray diffraction, X-ray photoelectron, and M?ssbauer spectroscopy in order to evidence the real cycling process and understand the cause of the material deactivation so that it can be suppressed or minimized for an industrial application. We found that the complete recovery of the initial cycling material was possible, but that a slow accumulation of coke took place over time under cycling conditions. Indeed, this deposited coke corresponds to only a part of the coke formed, since water makes partial re-oxidation possible. A third step to burn the coke left over by the air will thus have to be periodically added for a sustainable industrial process, unless a cycling material and/or certain conditions capable of either totally preventing the formation of coke or leading to the formation of coke that is not oxidized by water are found.

The Fischer–Tropsch synthesis (FTS) reaction is one of the most promising processes to convert alternative energy sources, such as natural gas, coal or biomass, into liquid fuels and other high-value products. Despite its commercial implementation, we still lack fundamental insights into the various deactivation processes taking place during FTS. In this work, a combination of three methods for studying single catalyst particles at different length scales has been developed and applied to study the deactivation of Co/TiO 2 Fischer–Tropsch synthesis (FTS) catalysts. By combining transmission X-ray microscopy (TXM), scanning transmission X-ray microscopy (STXM) and scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) we visualized changes in the structure, aggregate size and distribution of supported Co nanoparticles that occur during FTS. At the microscale, Co nanoparticle aggregates are transported over several μm leading to a more homogeneous Co distribution, while at the nanoscale Co forms a thin layer of ～1–2 nm around the TiO 2 support. The formation of the Co layer is the opposite case to the “classical” strong metal–support interaction (SMSI) in which TiO 2 surrounds the Co, and is possibly related to the surface oxidation of Co metal nanoparticles in combination with coke formation. In other words, the observed migration and formation of a thin CoO x layer are similar to a previously discussed reaction-induced spreading of metal oxides across a TiO 2 surface.

A substrate-binding-state mimic of H 2 O 2 -dependent cytochrome P450 that is able to catalyze monooxygenation of non-native substrates was constructed by one-point mutagenesis of P450 SPα (CYP152B1). P450 SPα , a long-alkyl-chain fatty acid hydroxylase, lacks any general acid–base residue around the heme. The carboxylate group of a fatty acid is thus indispensable for the generation of active species using H 2 O 2 . We prepared an A245E mutant to mimic a substrate-binding state by placing a carboxylate group at the active site. The active site structure of the A245E mutant is similar to that of the fatty-acid-bound state of P450 SPα and catalyzes styrene oxidation at a rate of 280 min ?1 ( k cat ), whereas the wild-type enzyme does not show any catalytic activity. More importantly, the same mutation, i.e. the mutation of the highly conserved threonine in P450s to glutamic acid, was also effective in introducing peroxygenase activity into P450BM3, P450 cam , and CYP119. These results indicate that a variety of peroxygenases based on P450s can be constructed by one-point mutagenesis.

Reaction methodology for C–H bond amination of benzene catalyzed by Mn( II )-dien (ampy) immobilized organo modified MCM-41 in the presence of hydroxylamine in acetic acid – water medium is described. The organic–inorganic hybrid heterogeneous catalyst achieves high catalytic activity and selectivity for one step amination of benzene . Characterization of the immobilized catalyst by powder X-ray diffraction ( XRD ), N 2 adsorption–desorption, CP MAS NMR spectroscopy ( 13 C and 29 Si), Fourier transform infrared spectroscopy ( FT-IR ) and diffuse reflectance UV–Vis spectroscopy demonstrates the successful grafting of the complex into functionalized mesoporous silica and that the mesostructure has not been destroyed in the multistep synthetic procedure. The variation of reaction conditions such as solvent , temperature, time, catalyst concentration etc . is well demonstrated to achieve high catalytic activity. Moreover, the anchored catalyst can be recovered and reused for multiple cycles without appreciable loss in catalytic activity, which is an alternative to the conventional industrial process.

Fischer–Tropsch synthesis (FTS) is a process which converts syn-gas (H 2 and CO) to synthetic liquid fuels and valuable chemicals. Thermal gasification of biomass represents a convenient route to produce syn-gas from intractable materials particularly those derived from waste that are not cost effective to process for use in biocatalytic or other milder catalytic processes. The development of novel catalysts with high activity and selectivity is desirable as it leads to improved quality and value of FTS products. This review paper summarises recent developments in FT-catalyst design with regards to optimising catalyst activity and selectivity towards synthetic fuels.

Being a most promising alternative to platinum-based catalysts for the oxygen reduction reaction, nitrogen-doped carbon materials have been extensively investigated to improve their electro-catalytic activity. In this work, a facile process involving an Fe precursor and annealing in an inert gas atmosphere is applied to the as-prepared carbon aerogel to reconstruct its surface. An optimized Fe-modified carbon aerogel (FCG-2) attains more macropores, more than 4 times higher surface nitrogen content and an elevated proportion of pyridinic nitrogen species. These enhancements result in improved ORR performance of this non-platinum catalyst, positively shifting E onset by 39 mV and E 1/2 by 14 mV compared to those of the initial carbon aerogel. FCG-2 used as an air cathode catalyst in a Zn–air battery exhibits excellent performance compared with that of a similarly prepared Pt/C cell. Post-synthesis surface reconstruction is feasible in improving the catalytic performance of newly prepared carbon materials.

Photocatalytic reduction of carbon dioxide (CO 2 ) into hydrocarbon fuels has attracted increasing research attention in recent years. However, the fast recombination of photoinduced charge carriers and poor adsorption/activation capability of CO 2 molecules limit the photoconversion efficiency. Herein, we report on loading a two-dimensional (2D) titanium carbide (Ti 3 C 2 ) MXene as a noble-metal-free cocatalyst onto zinc oxide (ZnO) via a facile electrostatic self-assembly method for efficient CO 2 photoreduction. It is interesting to find that the ZnO loaded with 7.5 wt% of surface-alkalinized Ti 3 C 2 exhibited remarkably improved evolution rates of CO (30.30 μmol g ?1 h ?1 ) and CH 4 (20.33 μmol g ?1 h ?1 ), which were approximately 7-fold and 35-fold those of bare ZnO, respectively. The surface-alkalinized Ti 3 C 2 MXene is believed to play a crucial role in improving the separation/transfer of photoinduced charge carriers and the adsorption/activation of CO 2 molecules, accounting for the superior photocatalytic activity of CO 2 reduction. Our work demonstrates that the Ti 3 C 2 MXene could be employed as a noble-metal-free cocatalyst for efficient photocatalytic CO 2 reduction.