Reactivity of nitrogen atoms from Zif-8 structure deposited over TiC MXene in the electrochemical nitrogen reduction reaction.

The electrochemical nitrogen reduction reaction (NRR) to produce NH is the most efficient, eco-friendly and cost-effective alternative to the Haber-Bosch process. It is crucial to investigate and develop electrocatalysts selective for NH synthesis. In recent studies, the TiC MXene has emerged as a highly promising electrocatalyst for the NRR process.

High-Surface-Area Synthesis of Iron-Doped CaTiO at Low Temperatures: New Insights into Oxygen Activation, Iron States, and the Impact on Methane Oxidation.

In the present work, a series of CaTiFeO (0 < < 0.5) materials are prepared using a modified Pechini method based on citric acid and a polyol as chelating agents. The synthesis conditions are optimized with respect to the specific surface area and phase purity by varying polyols (ethylene glycol, glycerol, and 1.

Combination of theoretical and in situ experimental investigations of the role of lithium dopant in manganese nitride: a two-stage reagent for ammonia synthesis.

Manganese nitride related materials are of interest as two-stage reagents for ammonia synthesis via nitrogen chemical looping. However, unless they are doped with a co-cation, manganese nitrides are thermochemically stable and a high temperature is required to produce ammonia under reducing conditions, thereby hindering their use as nitrogen transfer materials. Nevertheless, when lithium is used as dopant, ammonia generation can be observed at a reaction temperature as low as 300 °C.

Operando Isotopic Exchange in Solid Oxide Fuel Cells: Oxygen-Transport Dependency on Applied Potential.

The oxygen isotopic exchange technique is a powerful tool to investigate the oxygen transport kinetics in an oxide solid. In a solid oxide fuel cell, isotopic surface exchange and diffusion coefficients are classically determined by using the Isotopic Exchange Depth Profiling method followed by ex situ SIMS characterizations. Despite its relevance, the utilization of in situ or operando techniques to measure the isotopic exchange under an electrical bias remains marginal.

Remarkable active-site dependent HO promoting effect in CO oxidation.

The interfacial sites of supported metal catalysts are often critical in determining their performance. Single-atom catalysts (SACs), with every atom contacted to the support, can maximize the number of interfacial sites. However, it is still an open question whether the single-atom sites possess similar catalytic properties to those of the interfacial sites of nanocatalysts.

Unexpected redox behaviour of large surface alumina containing highly dispersed ceria nanoclusters.

Cerium-containing oxide materials have several very interesting applications due to their capacity to store and release oxygen under oxidizing and reducing conditions respectively. In the case of pure ceria this property is highly size dependent inasmuch as the phenomenon is limited to the surface and subsurface oxygen atoms. As a consequence, the design of nanocrystals of ceria has been attracting much attention.

Investigation of Methane Oxidation Reactions Over a Dual-Bed Catalyst System using O Labelled DRIFTS coupling.

Low loading Pd-supported (0.2 wt % Pd) Y-stabilized zirconia (YSZ) and LaMnO (LM) perovskite were associated to study the partial oxidation of methane using labelled O in the gas phase. Synthesis gas production was demonstrated to occur through an indirect reaction in which oxygen is first consumed in the total methane combustion.

Remarkable enhancement of O₂ activation on yttrium-stabilized zirconia surface in a dual catalyst bed.

Yttrium-stabilized zirconia (YSZ) has been extensively studied as an electrolyte material for solid oxide fuel cells (SOFC) but its performance in heterogeneous catalysis is also the object of a growing number of publications. In both applications, oxygen activation on the YSZ surface remains the step that hinders utilization at moderate temperature. It was demonstrated by oxygen isotope exchange that a dual catalyst bed system consisting of two successive LaMnO3 and YSZ beds without intimate contact drastically enhances oxygen activation on the YSZ surface at 698 K.

Clear microstructure-performance relationships in Mn-containing perovskite and hexaaluminate compounds prepared by activated reactive synthesis.

Microstructural properties of mixed oxides play essential roles in their oxygen mobility and consequently in their catalytic performances. Two families of mixed oxides (perovskite and hexaaluminate) with different microstructural features, such as crystal size and specific surface area, were prepared using the activated reactive synthesis (ARS) method. It was shown that ARS is a flexible route to synthesize both mixed oxides with nano-scale crystal size and high specific surface area.

A Study of N/N Isotopic Exchange over Cobalt Molybdenum Nitrides.

The N/N isotopic exchange pathways over CoMoN, a material of interest as an ammonia synthesis catalyst and for the development of nitrogen transfer reactions, have been investigated. Both the homomolecular and heterolytic exchange processes have been studied, and it has been shown that lattice nitrogen species are exchangeable. The exchange behavior was found to be a strong function of pretreatment with ca.

Preparation of crystal-like periodic mesoporous phenylene-silica derivatized with ferrocene and its use as a catalyst for the oxidation of styrene.

The surface silanol groups in crystal-like mesoporous phenylene-silica have been derivatized with trimethylsilyl, benzyldimethylsilyl and dimethylsilyl(ferrocene) groups by performing a post-synthetic grafting reaction with the corresponding chlorosilane precursors. The success of the grafting procedure was demonstrated by transmission FT-IR spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and (13)C and (29)Si magic-angle spinning (MAS) NMR spectroscopy. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and N2 adsorption data for the modified materials indicated preservation of the mesostructure as well as the molecular-scale periodicity in the pore walls.

Design of nanocrystalline mixed oxides with improved oxygen mobility: a simple non-aqueous route to nano-LaFeO3 and the consequences on the catalytic oxidation performances.

LaFeO3 nanoparticles, with improved oxygen mobility, leading to enhanced catalytic oxidation activities, are obtained through a simple nonaqueous route.

Design of nanocatalysts for green hydrogen production from bioethanol.

Bioethanol is an interesting feedstock that may be used for hydrogen production by steam or autothermal reforming. However, the impurities (heavy alcohols, esters, acids, N compounds) contained in the raw feedstock require a costly purification, as they have a dramatic impact on catalyst activity and stability. Thus, a method that can utilize the raw feedstock without severe degradation of the catalyst would be desirable.

Sulfonic acid functionalized crystal-like mesoporous benzene-silica as a remarkable water-tolerant catalyst.

Here we report that sulfonated crystal-like benzene-silica is much more robust and active than conventionally used periodic mesoporous silica for catalyzing aqueous organic reactions.

Improved oxygen mobility in nanosized mixed-oxide particles synthesized using a simple nanocasting route.

This work reports the synthesis of homogeneously dispersed mixed-oxide nanoparticles (<5 nm) exhibiting improved lattice oxygen mobility (ca. two times higher than on bulk samples), using a novel synthesis procedure of nanocasting in mesoporous silica host support.