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The catalytic hydrogenation of the toxic and harmful p-chloronitrobenzene to produce the value-added p-chloroaniline is an essential reaction for the sustainable chemical industry. Nevertheless, ensuring satisfactory control of its chemoselectivity is a great challenge. In this work, a N/S co-doped metal-free carbon catalyst has been fabricated by using cysteine as a source of C, N, and S. The presence of calcium citrate (porogen agent) in the mixture subjected to pyrolysis provided the carbon with porosity, which permitted us to overcome the issues associated with the loss of heteroatoms during an otherwise necessary activation thermal treatment. Full characterization was carried out and the catalytic performance of the metal-free carbon material was tested in the hydrogenation reaction of p-chloronitrobenzene to selectively produce p-chloroaniline. Full selectivity was obtained but conversion was highly dependent on the introduction of S due to the synergetic effect of S and N heteroatoms. The N/S co-doped carbon (CYSCIT) exhibits a mesoporous architecture which favors mass transfer and a higher doping level, with more exposed N and S doping atoms which act as catalytic sites for the hydrogenation of p-chloronitrobenzene, resulting in enhanced catalytic performance when compared to the N-doped carbon obtained from melamine and calcium citrate (MELCIT) used as a reference. [ABSTRACT FROM AUTHOR]

In the current work, carbon materials were used in the hydrogen adsorption process, specifically as carbons doped with platinum dispersed on ceria. The textural characterization results of the prepared samples and the starting carbon showed the presence of both micro‐ and mesopores. On the other hand, it has been observed that the specific areas were inversely proportional to the CeO2 loading. In addition, the amount of adsorbed hydrogen increased after doping the carbon with platinum and, even more, when the carbon was doped with Pt dispersed on ceria (2.2 mg/g at 25°C and 30 bar). However, there was a ceria optimum from which the adsorption capacity decreased (10% wt). The results of temperature‐programmed desorption (TPD) of hydrogen indicated a high affinity between Pt and H2 that enhanced H2 adsorption process by establishing chemical bonds between the metal particles and H2. Precisely, the presence of metallic Pt particles dispersed on ceria considerably promotes the spillover process of hydrogen on carbon. This can be confirmed by hydrogen adsorption–desorption isotherms, that showed that complete desorption of chemisorbed hydrogen required an increase of temperature. [ABSTRACT FROM AUTHOR]

Activated carbon (AC) is a common material of choice in catalysis, as it is a suitable support material for many catalytic reactions. In this work, the effect of cobalt nanoparticles on activated carbon derived from a biomass waste, peach stone, is reported. The presence of cobalt during heat treatments at 900 °C under reductive (H2) and inert (He) atmospheres resulted in the appearance of an intense 2D band in the Raman spectra, indicating a high degree of graphitization. Temperature-programmed reduction and desorption experiments were conducted to evaluate the activation reactions. Quenched solid density functional theory (QSDFT) analysis using N2 adsorption data revealed that cobalt increased pore development in the samples, regardless of the atmosphere (reductive or inert) used. [ABSTRACT FROM AUTHOR]

Metal-free catalysts based on nitrogen-doped porous carbons were designed and synthesized from mixtures of melamine as nitrogen and carbon sources and calcium citrate as carbon source and porogen system. Considering the physicochemical and textural properties of the prepared carbons, a melamine/citrate ratio of 2:1 was selected to study the effect of the pyrolysis temperature. It was observed that a minimum pyrolysis temperature of 750 °C is required to obtain a carbonaceous structure. However, although there is a decrease in the nitrogen amount at higher pyrolysis temperatures, a gradual development of the porosity is produced from 750 °C to 850 °C. Above that temperature, a deterioration of the carbon porous structure is produced. All the prepared carbon materials, with no need for a further activation treatment, were active in the hydrogenation reaction of 1-chloro-4-nitrobenzene. A full degree of conversion was reached with the most active catalysts obtained from 2:1 melamine/citrate mixtures pyrolyzed at 850 °C and 900 °C, which exhibited a suitable compromise between the N-doping level and developed mesoporosity that facilitates the access of the reactants to the catalytic sites. What is more, all the materials showed 100% selectivity for the hydrogenation of the nitro group to form the corresponding chloro-aniline. [ABSTRACT FROM AUTHOR]

MXenes are a new family of 2D carbides or nitrides that have attracted attention due to their layered structure, tunable surface groups and high electrical conductivity. Here, we report for the first time that the Ti2CTx MXene catalyses the selective oxidative dehydrogenation of n‐butane to butenes and 1,3‐butadiene. This catalyst showed higher intrinsic activity compared to a commercial TiC and TiO2 samples in terms of C4 olefin formation rate. We propose that the stabilisation of structural vacancies and the change in composition (from a carbide to a mixed phase oxide) in the MXene causes its higher catalytic activity. These vacancies can lead to a higher concentration of unpaired electrons in the MXene‐derived material, enhancing its nucleophilic properties and favouring the production of olefins. [ABSTRACT FROM AUTHOR]

The synthesis of methanol by carbon dioxide hydrogenation has been studied using copper-molybdenum carbides supported on high surface area graphite, reduced graphene oxide and carbon nanotubes. The synthesis conditions and the effect of the support were studied. The catalysts were prepared in situ using H2 or He at 600 °C or 700 °C. Both molybdenum carbide and oxycarbide were obtained. A support with less reactive carbon resulted in lower proportion of carbide obtained. The best results were achieved over a 5 wt.% Cu and 10 wt.% Mo on high surface area graphite that reached 96.3% selectivity to methanol. [ABSTRACT FROM AUTHOR]

Polypyrrole (PPy) has been prepared by oxidative polymerization of pyrrole and used as a raw material for the preparation of N‐doped activated carbons. Thus, PPy has been pyrolyzed at 900 °C and then activated with steam under different activation conditions (time and temperature). This has allowed for the preparation of activated carbons with different porosity development and nitrogen content, as well as distinctive distribution of nitrogen species. It has been observed that the presence of nitrogen functionalities favors water adsorption at low relative pressures but, at relative pressures higher than 0.5 it is determined by the porosity development. [ABSTRACT FROM AUTHOR]

The preparation of MOFs including a metal with an easily exchangeable oxidation state, while maintaining the same crystal structure and stability, is of paramount importance for myriad applications. In this work, a new synthesis method is reported that can be used to prepare Ce/Zr‐MOFs (UiO‐66 structure) having only Ce(III), a mixed‐valence Ce(IV)/Ce(III), or only Ce(IV) cations, as desired. The materials are characterized using a large number of techniques, including X‐ray absorption and X‐ray photoelectron spectroscopies. [ABSTRACT FROM AUTHOR]

MAX (Mn+1AXn) phases are layered carbides or nitrides with a high thermal and mechanical bulk stability. Recently, it was shown that their surface structure can be modified to form a thin non‐stoichiometric oxide layer, which can catalyze the oxidative dehydrogenation of butane. Here, the use of a Ti2AlC MAX phase as a support for cobalt oxide was explored for the dry reforming of butane with CO2, comparing this new catalyst to more traditional materials. The catalyst was active and selective to synthesis gas. Although the surface structure changed during the reaction, the activity remained stable. Under the same conditions, a titania‐supported cobalt oxide catalyst gave low activity and stability due to the agglomeration of cobalt oxide particles. The Co3O4/Al2O3 catalyst was active, but the acidic surface led to a faster deactivation. The less acidic surface of the Ti2AlC was better at inhibiting coke formation. Thanks to their thermal stability and acid‐base properties, MAX phases are promising supports for CO2 conversion reactions. [ABSTRACT FROM AUTHOR]

Catalytic hydrodeoxygenation (HDO) is a fundamental process for bio‐resources upgrading to produce transportation fuels or added value chemicals. The bottleneck of this technology to be implemented at commercial scale is its dependence on high pressure hydrogen, an expensive resource which utilization also poses safety concerns. In this scenario, the development of hydrogen‐free alternatives to facilitate oxygen removal in biomass derived compounds is a major challenge for catalysis science but at the same time it could revolutionize biomass processing technologies. In this review we have analysed several novel approaches, including catalytic transfer hydrogenation (CTH), combined reforming and hydrodeoxygenation, metal hydrolysis and subsequent hydrodeoxygenation along with non‐thermal plasma (NTP) to avoid the supply of external H2. The knowledge accumulated from traditional HDO sets the grounds for catalysts and processes development among the hydrogen alternatives. In this sense, mechanistic aspects for HDO and the proposed alternatives are carefully analysed in this work. Biomass model compounds are selected aiming to provide an in‐depth description of the different processes and stablish solid correlations catalysts composition‐catalytic performance which can be further extrapolated to more complex biomass feedstocks. Moreover, the current challenges and research trends of novel hydrodeoxygenation strategies are also presented aiming to spark inspiration among the broad community of scientists working towards a low carbon society where bio‐resources will play a major role. The development of hydrogen‐free alternatives to facilitate oxygen removal in biomass derived compounds is a major challenge for catalysis science but at the same time it could revolutionize biomass processing technologies. In this review, several novel approaches are analysed. The current challenges and research trends of novel hydrodeoxygenation strategies are also presented aiming to spark inspiration among the broad community of scientists working towards a low carbon society where bio‐resources will play a major role. [ABSTRACT FROM AUTHOR]

We report a facile and general approach for preparing ultrafine ruthenium nanocatalysts by using a plasma-assisted synthesis at <100 °C. The resulting Ru nanoparticles are monodispersed (typical size 2 nm) and remain that way upon loading onto carbon and TiO2 supports. This gives robust catalysts with excellent activities in both organosilane oxidation and the oxygen evolution reaction. [ABSTRACT FROM AUTHOR]

In this work, the WGS performance of a conventional Ni/CeO2 bulk catalyst is compared to that of a carbon-supported Ni-CeO2 catalyst. The carbon-supported sample resulted to be much more active than the bulk one. The higher activity of the Ni-CeO2/C catalyst is associated to its oxygen storage capacity, a parameter that strongly influences the WGS behavior. The stability of the carbon-supported catalyst under realistic operation conditions is also a subject of this paper. In summary, our study represents an approach towards a new generation of Ni-ceria based catalyst for the pure hydrogen production via WGS. The dispersion of ceria nanoparticles on an activated carbon support drives to improved catalytic skills with a considerable reduction of the amount of ceria in the catalyst formulation. [ABSTRACT FROM AUTHOR]

We analyzed the adsorption of CO2 in a Cu-BTC metal-organic framework (MOF) impregnated with ionic liquids (ILs) experimentally and by molecular simulation using the Monte Carlo method. The ILs [bmim][PF6] and [bmim][Tf2N] were impregnated in concentrations of 1, 5 and 10 wt%. Monte Carlo computations showed maximum impregnation load of approximately 30 wt% and improved CO2 adsorption up to 2 bar for all the concentrations tested. Experimentally, the impregnated material was carefully characterized and CO2 isotherms were measured. High concentrations of IL solution (10 wt%) had a pronounced detrimental effect on the textural properties of Cu-BTC, whereas for low concentration (5 wt%), no improvement in CO2 adsorption was observed. Based on the experimental and simulated data, the suitability of Cu-BTC as a target MOF for IL impregnation was examined. [ABSTRACT FROM AUTHOR]

Platinum nanoparticles supported on titania efficiently catalyzed the diboration of alkynes and alkenes under solvent- and ligand-free conditions in air. The cis-1,2-diborylalkenes and 1,2-diborylalkanes were obtained in moderate to excellent yields following, in most cases, a simple filtration workup protocol. The versatility of the cis-1,2-diboronvinyl compounds was demonstrated in a series of organic transformations, including the Suzuki-Miyaura cross coupling and the boron-halogen exchange. [ABSTRACT FROM AUTHOR]

The effects of treatment of an activated carbon with Sulphur precursors on its textural properties and on the ability of the complex synthesized for mercury removal in aqueous solutions are studied. To this end, a commercial activated carbon has been modified by treatments with aqueous solutions of Na2S and H2SO4 at two temperatures (25 and 140 °C) to introduce sulphur species on its surface. The prepared adsorbents have been characterized by N2 (-196 °C) and CO2 (0 °C) adsorption, thermogravimetric analysis, temperature-programmed decomposition and X-ray photoelectron spectroscopy, and their adsorption capacities to remove Hg(II) ions in aqueous solutions have been determined. It has been shown that the impregnation treatments slightly modified the textural properties of the samples, with a small increase in the textural parameters (BET surface area and mesopore volumes). By contrast, surface oxygen content was increased when impregnation was carried out with Na2S, but it decreased when H2SO4 was used. However, the main effect of the impregnation treatments was the formation of surface sulphur complexes of thiol type, which was only achieved when the impregnation treatments were carried out at low temperature (25 °C). The presence of surface sulphur enhances the adsorption behaviour of these samples in the removal of Hg(II) cations in aqueous solutions at pH 2. In fact, complete Hg(II) removal is only obtained with the sulphur-containing activated carbons. [ABSTRACT FROM AUTHOR]

The effect of a severe steaming treatment on the physicochemical properties and catalytic performance of H-SAPO-34 molecular sieves during the methanol-to-hydrocarbons (MTH) reaction has been investigated with a combination of scanning transmission X-ray microscopy (STXM), catalytic testing, and bulk characterization techniques, including ammonia temperature programmed desorption and 27Al and 29Si magic angle spinning nuclear magnetic resonance. For this purpose, two samples, namely a calcined and a steamed H-SAPO-34 catalyst powder, have been compared. It has been found that calcined H-SAPO-34 displays a high selectivity towards light olefins, yet shows a poor stability as compared to a zeolite H-ZSM-5 catalyst. Moreover, in situ STXM at the carbon K-edge during the MTH reaction allows construction of nanoscale chemical maps of the hydrocarbon species formed within the H-SAPO-34 aggregates as a function of reaction time and steam post-treatment. It was found that there is an initial preferential formation of coke precursor species within the core of the H-SAPO-34 aggregates. For longer times on stream the formation of the coke precursor species is extended to the outer regions, progressively filling the entire H-SAPO-34 catalyst particle. In contrast, the hydrothermally treated H-SAPO-34 showed similar reaction selectivity, but decreased activity and catalyst stability with respect to its calcined counterpart. These variations in MTH performance are related to a faster and more homogeneous formation of coke precursor species filling up the entire steamed H-SAPO-34 catalyst particle. Finally, the chemical imaging capabilities of the STXM method at the Al and Si K-edge are illustrated by visualizing the silicon islands at the nanoscale before and after steaming H-SAPO-34. [ABSTRACT FROM AUTHOR]

The textural characterization of a series of activated carbons prepared from olive stones, by carbonization at different temperatures (400, 550, 700 and 850 °C) and thermal activation with CO, has been investigated using N adsorption at −196 °C and CO adsorption at 0 °C. The effect of pre-oxidation of the carbonized precursor has also been studied, using temperature-programmed decomposition (TPD), to evaluate the effect of oxygen content of the chars in the performance of the obtained activated carbons for mercury removal. The adsorption of Hg(II) cations from aqueous solutions at room temperature by the prepared activated carbons was studied. Experimental results show that all samples exhibit a large microporosity (pore diameter below 0.56 nm). The amount of surface oxygen groups increased after pre-oxidation treatment, this enhancing the Hg(II) uptake (up to 72%). It can be concluded that these groups make the support more hydrophilic, thus providing a more efficient adsorption of Hg(II). The formation of a great amount of surface oxide groups such as carboxyl, phenol and lactone alters the surface charge properties of the carbon, this enhancing the surface-Hg(II) interaction. [ABSTRACT FROM AUTHOR]

(111) preferentially oriented Pt nanoparticles supported on expanded graphite were prepared by impregnation of the support with an aqueous solution of H2PtCl6. The catalyst was characterized by a number of techniques and tested in the liquid-phase hydrogenation of cinnamaldehyde. The preferential surface orientation of the metal particles favours a very high selectivity towards the hydrogenation of the carbonyl bond of cinnamaldehyde to yield cinnamyl alcohol. The performance of this catalytic system is comparable to that obtained with similar catalysts prepared by more complex methods. Furthermore, expanded graphite provides a good alternative as support to other graphitic materials such as carbon nanotubes and carbon nanofibres. [ABSTRACT FROM AUTHOR]

This paper reports a CO adsorption study on a Pt/TiO2catalyst reduced at two different temperatures, 473 and 773 K, followed by in situinfrared spectroscopy and adsorption microcalorimetry. The study is complemented with XPS characterization of the reduced catalysts. [ABSTRACT FROM AUTHOR]

Activated carbon-supported cerium dioxide (CeO2/C) was prepared by impregnation of a commercial support (Norit R2030) with aqueous solutions of two different cerium precursors, [(NH4)2Ce(NO3)6] and Ce(NO3)3·6H2O. The effect of carbon surface chemistry on the dispersion of ceria was studied by using two different carbon supports, the R2030 and the same material after an oxidation treatment with H2O2. Thus, four samples were obtained by combining the precursors and the supports. The prepared materials were characterized by thermogravimetry, nitrogen adsorption isotherms (77 K), X-ray diffraction, temperature-programmed desorption, temperature-programmed reduction and transmission electron microscopy, in order to study the degree of ceria dispersion over the supports. It was found that the best results in terms of ceria dispersion were obtained for the material prepared with the oxidized carbon and ammonium cerium nitrate as cerium precursor. [ABSTRACT FROM AUTHOR]

Microcalorimetric measurements of the adsorption of H2 and C2H4 were carried out at 300 K on a Pt–Zn/X-zeolite catalyst (Pt : Zn atomic ratio equal to 1 : 1). The initial heats of H2 and C2H4 adsorption were equal to 75 and 122 kJ/mol, respectively, and these values are weaker than the values of 90 and 155 kJ/mol typically observed for supported Pt catalysts. Reaction kinetics measurements for isobutane dehydrogenation over the Pt–Zn/X-zeolite catalyst were carried out at temperatures from 673 to 773 K, at isobutane pressures from 0.01 to 0.04 atm, and at hydrogen pressures from 0.1 to 0.7 atm. The catalyst shows high activity and selectivity for dehydrogenation of isobutane to isobutylene. The reaction kinetics can be described with a Horiuti–Polanyi reaction scheme. DFT calculations were carried out for the adsorption of ethylene on slabs of Pt(111), Pt3Zn(111) and PtZn(011). Results from these calculations indicate that addition of Zn to Pt weakens the binding energies of π-bonded ethylene, di-σ-bonded ethylene, and ethylidyne species on atop, bridged, and three-fold Pt sites, respectively. These effects are most significant for the bonding of ethylidyne species, and they are least significant for π-bonded ethylene species. Results from DFT calculations for the adsorption of formaldehyde show that addition of Zn to Pt weakens the di-σ-bonding at Pt–Pt sites; however, this weakening effect of Zn on formaldehyde adsorption is less significant than the effect on ethylene adsorption. Moreover, the preferred location for adsorption of formaldehyde on PtZn(011) is a Pt–Zn site, whereas the preferred location for adsorption of ethylene is a Pt–Pt site. Thus, formaldehyde is adsorbed more strongly by 53 kJ/mol on PtZn(011) compared to the di-σ-adsorption of ethylene, whereas formaldehyde and ethylene adsorb in the di-σ-forms with comparable energies on Pt(111). This preferred adsorption of formaldehyde compared to ethylene on PtZn(011) may be at least partially responsible for the enhanced selectivity of Pt–Zn-based catalysts for hydrogenation of C=O groups compared to C=C bonds in α,β-unsaturated aldehydes. [ABSTRACT FROM AUTHOR]

Bio-hydrogenated diesel (BHD), derived from vegetable oil via hydrotreating technology, is a promising alternative transportation fuel to replace nonsustainable petroleum diesel. In this work, a novel Pt-based catalyst supported on N-doped activated carbon prepared from polypyrrole as the nitrogen source (Pt/N-AC) was developed and applied in the palm oil deoxygenation process to produce BHD in a fixed bed reactor system. High conversion rates of triglycerides (conversion of TG > 90%) and high deoxygenation percentage (DeCOx% = 76% and HDO% = 7%) were obtained for the palm oil deoxygenation over Pt/N-AC catalyst at optimised reaction conditions: T = 300 °C, 30 bar of H2, and LHSV = 1.5 h−1. In addition to the excellent performance, the Pt/N-AC catalyst is highly stable in the deoxygenation reaction, as confirmed by the XRD and TEM analyses of the spent sample. The incorporation of N atoms in the carbon structure alters the electronic density of the catalyst, favouring the interaction with electrophilic groups such as carbonyls, and thus boosting the DeCOx route over the HDO pathway. Overall, this work showcases a promising route to produce added value bio-fuels from bio-compounds using advanced N-doped catalysts. [ABSTRACT FROM AUTHOR]

The Cover Feature shows the application of an easily prepared ultrafine ruthenium nanocatalyst to both the organosilane oxidation and the oxygen evolution reactions. In their Communication, E. S. Gnanakumar et al. describe the facile and general preparation of monodispersed superior ruthenium metal catalysts by using a plasma‐assisted synthesis at <100 °C. The method could be applied successfully for multiple supports. More information can be found in the Communication by E. S. Gnanakumar et al. on page 4159 in Issue 22, 2017 (DOI: 10.1002/cctc.201700809). [ABSTRACT FROM AUTHOR]

An editorial about the life and work of chemistry teacher F. Rodríguez-Reinoso is presented. The authors described the personal life and education background of Rodríguez-Reinoso. They mentioned the decision of Rodríguez-Reinoso to explore the field of materials science. They expressed their gratitude to the work of guest editors on the special issue about Rodríguez-Reinoso.