TinCn−1Tx2D-sheets are functionalized using a new etching environment allowing the modification of their surface chemistry and production of rationalized TiO2@MXene nanocomposites.

A simple template-free method, based on a mineral acid etching process using manganite perovskite (LaMnO 3) as precursor, was successfully developed to obtain a series of 3D meso/macro-porous materials. The LaMnO 3 transformation was fully investigated using ICP, XRD, N 2 physisorption, TPR, TPD, SEM, TEM/EDS and XPS. This transformation proceeds through a soft-chemical process involving the dissolution of trivalent lanthanum and manganese from the perovskite structure and the dismutation of Mn 3+ cations into MnO 2 and Mn 2+ species. Strength and oxidizing properties of the acid used as modifying agent strongly impact textural and redox surface properties of the resulting materials. Specifically, extending the acid etching duration promotes the surface area and pore volume of the materials while developing interconnected macro-mesoporous networks. In our case, this soft process allowed us to obtain the ε-MnO 2 phase with hierarchical porosity without any template. Superior catalytic properties of ε-MnO 2 were observed toward HCHO oxidation as well as a good catalytic stability with respect to other macro-mesoporous counterparts. In the light of the experimental results, such performances can be related to the formation of a meso/macro-porous structure conferring high surface area and good accessibility of the active surface sites. The latter exhibit greater redox ability of the manganese species and a higher density of active surface oxygen species with respect to the perovskite precursor.

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Activated reactive synthesis, as a top‐down synthesis approach, is proposed for the production of a nanocrystalline, high surface area, manganese (IV) oxide starting from commercial micrometric α‐MnO2. The developed approach consists of two‐steps: 1) high energy ball milling (HEBM) produces a nano‐sized material, 2) low energy ball milling (LEBM) improves textural properties. During the HEBM step, elementary crystals are observed to evolve from several hundred elongated cylindrical particles to short length cylinders and pseudo spherical particles. Despite fractioning of the elementary crystals, surface area remains low over the HEBM derived solid. The LEBM step, achieves crystal shape modification, giving rise to only pseudo‐spherical nanometric particles and significantly increasing the surface area to approximately 60–80 m2 g−1. Catalytic activity of α‐MnO2 powder is affected by the grinding process. Activity is similar to the fresh commercial MnO2 after HEBM, and increases upon LEBM reaching a maximum for LEBM time of 1 h. Thereafter, activity remains constant despite the further increase in surface area upon prolonged LEBM. The presence of an optimal activity after limited LEBM time is paralleled with the increase of the iron contamination occurring after prolonged LEBM time which impacts manganese reducibility and results in less reactive surface.

Cobalt enables formation of additional oxygen vacancies in Au/Co–CeO2 and significantly boosts the ambient oxidation of formaldehyde.

Catalytic total oxidation is an efficient technique for treating VOCs, which are mainly emitted by solvent-based industrial processes. However, studies of the catalytic oxidation of VOCs in combination with other pollutants are very limited, despite the fact that this is a key step of knowledge before industrial application. During the oxidation reaction, the behavior of a molecule may change depending on the reaction mixture. For the treatment of an effluent loaded with VOCs, it is necessary to carefully select not only the catalytic material to be used but also the reaction conditions. Indeed, the catalytic oxidation of a component in a VOCs mixture is not predicted solely from the behavior of individual component. Thus, the objective of this small review is to carry out a study on the effect observed in the case of the oxidation of a VOCs mixture or in the presence of water, NOX or sulfur compounds.

Conventional melt infiltration (over calcined SBA‐15 silica support) and optimized melt infiltration (over surfactant‐containing SBA‐15 support) were used for the first time to prepare MnOx nanoparticles encapsulated within the support pores. A comprehensive study on the evolution of textural, structural, and morphological characteristics of the MnOx‐silica composites as well as their redox and surface properties is reported herein by varying synthesis parameters, such as manganese loading (5, 10, 20 and 30 Mn wt.%), and post‐treatment temperature (300 and 500 °C). The catalytic performances of the materials prepared in this work have been evaluated in the catalytic oxidation of formaldehyde. The results show a high performance of the SBA‐15 supported manganese oxide at low‐ to moderate‐ temperatures of reaction (Temperature at 50 % of HCHO conversion into CO2 ranging from 110° to 150 °C), activity being related to Mn oxidation state (from 2.3 to 4) and MnOx phase location, confined with or without 2D spatial distribution in the support porosity or formed at the external surface of SBA‐15. A high stability (60 hours), under dry air and 50 % relative humidity air, is reported for MnOx‐based nanocatalysts prepared by conventional and optimized melt infiltration procedures.

CuAlCe oxides were obtained from hydrotalcite-type precursors by coprecipitation using a M2+/M3+ ratio of 3. The collapse of the layered double hydroxide structure following the thermal treatment leads to the formation of mixed oxides (CuO and CeO2). The catalytic performance of the copper-based catalysts was evaluated in the total oxidation of two Volatile Organic Compounds (VOCs): ethanol and toluene. XRD, SEM Energy-Dispersive X-ray Spectrometry (EDX), H2-temperature programmed reduction (TPR) and XPS were used to characterize the physicochemical properties of the catalysts. A beneficial effect of combining cerium with CuAl-O oxides in terms of redox properties and the abatement of the mentioned VOCs was demonstrated. The sample with the highest content of Ce showed the best catalytic properties, which were mainly related to the improvement of the reducibility of the copper species and their good dispersion on the surface. The presence of a synergetic effect between the copper and cerium elements was also highlighted.