Vapor-Phase Oxidation of Benzyl Alcohol Using Manganese Oxide Octahedral Molecular Sieves (OMS-2)

Vapor-phase selective oxidation of benzyl alcohol has been accomplished using cryptomelane-type manganese oxide octahedral molecular sieve (OMS-2) catalysts. A conversion of 92% and a selectivity to benzaldehyde of 99% were achieved using OMS-2. The role played by the oxidant in this system was probed by studying the reaction in the absence of oxidant. The natures of framework transformations occurring during the oxidation reaction were fully studied using temperature-programmed techniques, as well as in situ X-ray diffraction under different atmospheres

Nonaqueous route toward a nanostructured hybrid titanate

International audienc

Chromium nitride and carbide nanofibers: from composites to mesostructures

This work describes an easy two-step approach for metal nitride/carbide nanocomposite ceramic nanofibers via heat treatment of electrospun precursor fibers. Possibilities to tune their composition, carbon scaffold organization and texture depend on the calcination temperature, and yield two different types of fiber structures. Fiber mats with various morphologies were obtained from polyacrylonitrile–chromium chloride precursor electrospun fibers, while well defined rod-like fiber non-woven mats were obtained when a methylated polyurea was used as an additive to the previous system. It was observed that the use of a two component organic system, involving a fiber stabilizing polymeric template (PAN) and a specific nitrogen/carbon donor (PUF), enables to maintain the morphology of the initial fibers during heat treatment and prevents the system from forming sintered membranes at high humidity conditions. The chromium content found for PAN-free and PAN-containing was 9 and 12 wt%, respectively. Moreover, thermal treatment at temperatures higher than 1000 °C led to graphitization of the carbon subphase of both series. Nitrogen sorption studies revealed that the graphitization process increases the specific surface area of the fibers, which possess a pore system with a wide diameter distribution and inkbottle-shaped pores. Conductivity studies revealed that the fiber systems are suitable for electrochemical applications

Evolution of Nanostructured Manganese (Oxyhydr)oxides in Water through MnO4 - Reduction.

International audienc

Twinning Driven Growth of Manganese Oxide Hollow Cones through Self-Assembly of Nanorods in Water

International audienc

Structural and morphological control of manganese oxide nanopartciles upon soft aqueous precipitation through MnO4 -/Mn2+ reaction

International audienc

Selective Heterogeneous Oriented Attachment of Manganese Oxide Nanorods in Water : Toward 3D Nanoarchitectures.

International audienc

Synthesis of a manganese oxide nanocomposite through heteroepitaxy in aqueous medium

International audienc

Integrative Sol-Gel Chemistry

Integrative chemistry is the link between the notions of “complexity in chemistry” and the bio-inspired integrative synthesis. This chapter relies on this vein of integrative chemistry, while dealing with sol-gel chemistry. Through the sol–gel-based integrative chemistry, it shows how it is possible to trigger materials dimensionality and beyond their functionalities when reaching enhanced applications. Thereby it selectively proposes the morphosyntheses of discrete objects, 1D materials (fibers), 2D arrays (films), and 3D macrocellular foams bearing hierarchical porosities (monoliths). The chapter discusses in detail how integrative chemistry allows fine-tuning of material shapes and dimensions while offering enhanced applications. Considering the shaping modes, it also deals with how the integrative chemistry allows positioning the chemical reactors within the geometric spaces, with specific competence appearing as a novel paradigm with regard to traditional sol-gel chemistry