Photocatalysis is a green technology which converts abundantly available photonic energy into useful chemical energy.

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The development of chemically compatible microsystems that can operate across expanded process conditions, such as high pressures (HP) and high temperatures (HT), is of great interest for many applications, including high pressure chemistry and hydrothermal and supercritical fluid processes. We present a methodology for the successful design and use of HP/HT microsystems. Key parameters for the fabrication of microreactors and modular fluidic packaging able to withstand severe pressure and temperature conditions (30 MPa, 400 °C) are described. Applications of these HP/HT plug and play microsystems are illustrated with examples, including multiphase flow visualization through the transition of liquid-liquid immiscible hexane-water segmented flow to homogeneous supercritical flow, on chip supercritical water oxidation, and synthesis of iron oxide nanoparticles.

Highlights * Main recycling technologies for carbon fibre reinforced plastics (CFRPs) * Advantages and disadvantages for each technology * Focus on the chemical recycling of CFRPs using a solvolysis process in near of supercritical fluids * REcycling Carbon fibre reinforced Composites (RECCO) project *Highlights

Supercritical fluids offer fast and facile routes toward well-crystallized tailor-made cerium oxide nanoparticles. However, the use of surfactants to control morphology and surface properties remains essential. Therefore, although water, near-critical (nc) or supercritical (sc), is a solvent of choice, the poor water solubility of some surfactants could require other solvent systems such as alcohols, which could themselves behave as surface modifiers. In here, the influence of seven different alcohols, MeOH, EtOH, PrOH, iPrOH, ButOH, PentOH, and HexOH, in alcothermal conditions (300 °C, 24.5 MPa) over CeO(2) nanocrystals (NCs) size, morphology, and surface properties was investigated. The crystallite size of the CeO(2) nanocrystals can be tuned in the range 3-7 nm depending on the considered alcohol, and their surface has been modified by these solvents without the use of surfactants. Mechanisms are proposed for the interaction of primary and secondary alcohols with CeO(2) surface and its functionalization during the synthesis based on FTIR and TGA-MS studies. This study allows apprehending the role of alcohols during the synthesis and may lead to an informed choice of solvent as a function of the required size and surface properties of CeO(2) NCs. It also opens new route to CeO(2) functionalization using supercritical alcohol derivatives.

International audienceThis paper describes how the specific properties of supercritical fluids have been exploited in the last 5 years for synthesizing functional nanostructured materials, especially in the field of inorganic and hybrid materials. It is shown that control of the physicochemical properties of nanomaterials (size, morphology, structure and composition) as "nanobricks" is achieved by choosing specific operating parameters. Next, the structure formation of these "nanobricks" is discussed in order to design advanced nanostructured materials. This is illustrated with the design of nanorods, nanowires, conformational films, core-shell structure, supported nanoparticles, polymer impregnation with nanoparticles and organic coating of particles. The associated properties for applications in many interesting fields, such as catalysis, electronics, energy, optics, etc. are reported