[en] Molybdenum disulfide with unique mesoporous structure was synthesized from tetraalkylammonium thiometallate precursors in situ decomposed in a batch reactor in the presence of dibenzothiophene (DBT). The precursors used in this study were tetraalkylammonium thiomolybdates with alkyl groups ranging from propyl to octyl. Molybdenum disulfide thus prepared presents high surface area (from 255 up to 329 m²/g), high content of carbon (C/Mo=2.7-4.0) and type IV nitrogen adsorption-desorption isotherms when decomposed from tetrahexyl-, tetraheptyl- or tetraoctylammonium thiomolybdates. The as-formed materials are poorly crystallized with a very weak intensity of the (0 0 2) peak of the 2H-MoS₂ structure. Such diffraction patterns are characteristic of exfoliated samples. Characterization by TEM shows a disordered layered structure with no long range order for the MoS₂ catalysts. Therefore, the nature of the alkyl group in the precursor affects both the surface area and the pore size distribution of the final MoS₂ catalysts with a progressive morphological modification up to a mesoporous organization

[en] This huge publication contains contributions and sessions of a conference which addressed the following issues: new abilities and professions in the energy sector, perspectives for local and energy policies and for the society after the COP21 and the role of local communities (tools and actions, education, development of cold networks, and so on), a discussion about what happened during the past year with notably the French law for energy transition and a green growth, an overview of the GRHYD demonstrator (the first Power-to-Gas demonstrator in France), how to finance energy transition, how to shift towards a societal transition, sustainable mobility (a city without car made by its inhabitants), urban agriculture as a lever for action for energy transition, the role of citizen in tomorrow's energy, the post-COP21 European, national and local agenda, energy transition and jobs. Workshops and forums related to various aspects related to these issues are also reported

[en] Two sets of articles addressing issues related to ecological transition are proposed. The first one addresses general aspects and transverse tools related to governance (governance and involved institutions, ecological transition and other transitions), to law (on climate and on the environment), to technology (development of a low tech), to economy (physical risks and adaptation), and to circular economy (main actors, national strategy, limitations, wastes, waste waters). It also addresses aspects related to natural resources, biodiversity, wastes and pollutions (green energies and metals, food, climate and economy, biodiversity) and to climate change (adaptation and resilience, greenhouse gas emissions and energy). The second part more particularly focuses on the importance of decision processes at a territorial level. This comprises a global approach (safety for ecological transitions within a digital era, sustainable development, ethics and standards), and aspects related to the energy policy, to adaptation policy and to mitigation policy, to economy and to a territorial approach

[en] Highlights: • Polyhydroxyfullerene (PHF) decorating TiO_2 nanostructured materials. • PHF helps to maintain surface oxygen vacancies at the TiO_2 surface. • PHF improves the faradic current across the semiconductor interface. • Higher photocatalytic activity is achieved for monolayer PHF onto TiO_2 nanotubes. - Abstract: The influence of polyhydroxyfullerene (PHF) on the photocatalytic properties of calcined hydrogenotitanate nanotubes (HNT) were evaluated in the present study. PHF-HNT nanocomposites were first characterized by N_2 adsorption-desorption measurements, X-ray diffraction, X-ray photoelectron, electron paramagnetic resonance and UV–vis diffuse reflectance spectroscopies, transmission electron microscopy, photoluminescence, and photocurrent experiments. Correlation was then established with the photocatalytic properties of PHF-HNT nanocomposites during the photodegradation of formic acid.

[en] Hydrotreatment catalytic operations are commonly performed industrially by layered molybdenum sulfide promoted by cobalt or nickel in order to remove heteroelements (S, N, O) from fossil fuels and biofuels. Indeed, these heteroelements are responsible of the emission of pollutants when these fuels are used in vehicles. In this respect, previous studies made by our research group have shown that the active phase under steady state conditions is partially carbided while strong bending effects of MoS₂ slabs were also observed. However, up to now, the morphology of the resulting Co/MoS_xC_y carbided catalyst has not been fully characterized. In the present study, for the first time, a chemical reaction between the carbon content of a TEM Cu/C grid and a freshly sulfide Co/MoS₂ catalyst was in situ observed at 300 °C and 450 °C by HRTEM experimental techniques at ∼10 nm of resolution. Results indicate that bending of MoS₂ layers occurred due to carbon addition on MoS₂ edge sites, as observed in stabilized catalysts after HDS reaction. Using a silicon grid, only cracks of MoS₂ slabs were observed without bending effect confirming the role of structural-carbon in this change of morphology

[en] One-pot deposition of Au onto TiO₂ has been achieved through directly contacting gold (III) salt with nanosized functionalized TiO₂ support initially obtained by sol–gel process using titanium isopropoxide and citric acid. Citrate groups act as functional moieties able to directly reduce the Au salt avoiding any further reducing treatment. Various gold salts (NaAuCl₄·2H₂O or HAuCl₄·3H₂O) and titanium to citrate (Ti/Cit) molar ratios (20, 50 and 100) were used in order to study the effect of the nature of the precursor and of the citrate content on the final Au particle size and catalytic properties of the as-obtained Au/TiO₂ materials. Au/(TiO₂)_x(Cit)₁ catalysts characterization was performed using N₂ adsorption–desorption, ICP-AES, X-ray diffraction and TEM. The effect of the Ti/Cit molar ratio and of the gold precursor was evaluated. The selective oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzH) was studied as a model reaction. Kinetic analysis showed that the catalytic reaction rate was pseudo first-order and the values of activation energy have been reported. Results showed that the functionalization of TiO₂ by citrate allows tuning the size of the Au nanoparticles deposited onto TiO₂ as well as their morphology. Citrate also strongly enhances the benzyl alcohol oxidation through the control of the size and morphology of gold nanoparticles. - Highlights: • One-pot deposition of Au onto TiO₂ has been achieved. • Citrates act as active sites for selective deposition and reduction of gold. • The presence of citrates influences the size and the morphology of gold NPs. • Au NPs with well-defined morphologies were obtained for Cit/Ti molar ratio of 100. • The selective oxidation of benzyl alcohol was studied as a model reaction

[en] Highlights: • Pt/CNT/TiO₂ electrocatalyst was successfully prepared by the sonochemical method. • The electrocatalyst Pt/CNT/TiO₂ was synthesized without heat treatments, additives or surfactants. • The TiO₂-Pt interaction improves the CO-tolerance of Pt/CNT/TiO₂, as well as the electrocatalyst stability. • Low amount of multi-walled carbon nanotubes increases the current density of Pt/CNT/TiO₂ significantly compared to Pt/TiO₂. - Abstract: Pt electrocatalyst supported on composite formed of multi-walled carbon nanotubes and titanium oxide (CNT/TiO₂) was successfully synthesized by a sonochemical method without heat treatments, surfactants or additives. This electrocatalyst could be used for direct methanol fuel cells (DMFC) applications. For comparison, Pt/CNT and Pt/TiO₂ electrocatalysts were prepared as reference samples. Structural properties and morphology of the synthesized materials were examined by X-ray diffraction, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and their specific surface areas were determined by the Brunauer-Emmett-Teller method. The Pt and acid-treated CNT contents were analyzed by inductively coupled plasma atomic emission spectroscopy and thermogravimetric analysis, respectively. The electrochemical properties of the synthesized electrocatalysts were evaluated by cyclic voltammetry (CV) and chronoamperometry in a three-electrode cell at room temperature. The evaluation performed using electrochemical techniques suggests that TiO₂ promotes the CO-tolerance due to TiO₂-Pt interaction. The CV tests demonstrated that 6 wt.% of acid-treated CNT increases significantly the current density when Pt selectively interacts with TiO₂.