Walid Baaziz

Walid Baaziz
French National Centre for Scientific Research | CNRS · IPCMS UMR7504

Doctor of Engineering

About

92
Publications
15,743
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,695
Citations
Additional affiliations
February 2016 - present
Institut de Physique et Chimie des Matériaux de Strasbourg
Position
  • PostDoc Position
Description
  • Tomographie électronique Microscopie électronique à transmission environnementale
February 2012 - December 2015
University of Strasbourg
Position
  • PostDoc Position

Publications

Publications (92)
Article
Full-text available
The precise bottom-up synthesis of graphene nanoribbons (GNRs) with controlled width and edge structures may compensate for graphene's limitations, such as the absence of an electronic bandgap. At the same time, GNRs maintain graphene's unique lattice structure in one dimension and provide more open-edge structures compared to graphene, thus allowi...
Article
Full-text available
A multiscale 3D approach combining three advanced volumetric imaging techniques was employed for obtaining direct information on the hierarchical porosity in Coscinodiscus sp. diatoms having an internal organization ranging from micrometer to nanometer.
Article
Single-atom catalysts represent an intense topic of research due to their interesting catalytic properties for a wide range of reactions. Clarifying the nature of the active sites of single-atom catalysts under realistic working conditions is of paramount importance for the design of performant materials. We have prepared an Ir single-atom catalyst...
Article
Full-text available
Many magnetotactic bacteria (MTB) biomineralize magnetite crystals that nucleate and grow inside intracellular membranous vesicles originating from invaginations of the cytoplasmic membrane. The crystals together with their surrounding membranes are referred to as magnetosomes. Magnetosome magnetite crystals nucleate and grow using iron transported...
Article
Catalytic processes in water have a lower environmental impact, cost, and toxicity than in organic solvents. Considering the high content of water in biomass, it would be natural to use aqueous phase catalytic technology for the production of valuable products. However, in the aqueous phase, most metal-based catalysts suffer from low activity, low...
Article
Full-text available
The structure of catalyst containing Ni nanoparticles (NPs) supported over carbon nanofibers/few layer graphene (CNFs/FLG) was tailored via modification of chemical vapor deposition parameters in view of methanation of CO2 under induction heating mode (IH). High edges-to- graphitic plane ratio in the support achieved due to the specific herringbone...
Article
Full-text available
Molecular imprinting of polymer matrices enables the creation of template-shaped cavities with high affinity for molecules of given shape and size. Here we introduce a surface molecular imprinting strategy to control the hydrogenation selectivity of various aromatic molecules over a supported palladium catalyst. This strategy involves the sequentia...
Article
The preferential oxidation of CO in H2-rich mixtures (COPrOx) is a major catalytic reaction utilized for hydrogen purification. In the exploration of alternatives to noble metals, cobalt-based catalysts appear to be a very promising choice. The activity and stability of cobalt in the COPrOx reaction can be improved by the addition of transition met...
Article
Preferential oxidation of CO (COPrOx) is a catalytic reaction targeting the removal of trace amounts of CO from hydrogen-rich gas mixtures. Non-noble metal catalysts, such as Cu and Co, can be equally active to Pt for the reaction; however, their commercialization is limited by their poor stability. We have recently shown that CoO is the most activ...
Article
Activated carbon containing highly dispersed platinum (Pt/C with ca. 1 wt.%) catalyst was synthesized according to the simple sonochemistry route followed by a drying step in air at 130°C. STEM-HAADF micrographs indicate the presence of Pt single atoms (SAs) homogeneously dispersed on the activated carbon. The catalytic decomposition of NO has been...
Article
Full-text available
Mixed‐dimensional heterostructures formed by the stacking of 2D materials with nanostructures of distinct dimensionality constitute a new class of nanomaterials that offers multifunctionality that goes beyond those of single dimensional systems. An unexplored architecture of single electron transistor (SET) is developed that employs heterostructure...
Article
Ultrathin palladium nanosheets on carbon black grains have been straightforwardly prepared under reductant-free conditions using ultrasonication. The as-prepared composites (showing a quite unusual morphology of Pd-deposits) have been scrutinized as catalysts in the selective alkyne-to-alkene hydrogenation under mild operational conditions. Their a...
Article
The catalytic hydrogenation of CO2 to formic acid is one of the most promising pathways towards a renewable hydrogen-storage system. The reaction is usually performed in aqueous phase in the presence of basic molecules over homogeneous or heterogeneous catalysts, generating relatively dilute formate solutions (<1 M). The newly designed solid micell...
Article
Supported metal catalysts have found broad applications in heterogeneous catalysis. In the conventional bifunctional catalyst, the active metal sites are associated with the metal nanoparticles, while the acid sites are usually localized over the oxide support. Herein, we report a novel type of supported metal bifunctional catalyst, which combined...
Article
Full-text available
Mixed-dimensional heterostructures formed by the stacking of 2D materials with nanostructures of distinct dimensionality constitute a new class of nanomaterials that oers multifunctionality that goes beyond those of single dimensional systems. An unexplored architecture of single electron transistor (SET) is developed that employs heterostruct...
Article
Full-text available
Supported single atoms constitute excellent models for understanding heterogenous catalysis and have achieved breakthroughs during the past years. How to prevent the aggregation and modulate activity of these species via metal‐support interaction should be considered for practical applications. This work presents simple methods involving the creati...
Article
Full-text available
Superparamagnetic Zn x Fe 3−x O 4 magnetic nanoparticles (0 ≤ x < 0.5) with spherical shapes of 16 nm average diameter and different zinc doping level have been successfully synthesized by co-precipitation method. The homogeneous zinc substitution of iron cations into the magnetite crystalline structure has led to an increase in the saturation magn...
Article
Major current challenges in nano-biotechnology and nano-biomedicine include the implementation of predesigned chemical reactions in biological environments. In this context, heterogeneous catalysis is emerging as a promising approach to extend the richness of organic chemistry onto the complex environments inherent to living systems. Herein we repo...
Article
Nowadays, the best thermal insulators are aerogel-based materials. However, their industrial application is constrained by a complex synthesis route (requiring supercritical drying) and by their fragility. Moreover, the most common aerogels, based on amorphous SiO2, have a poor thermal stability. In this work, a fast and simple synthesis route to u...
Article
A Pd1/α‐MoC catalyst with high mass loading could endure harsh reducing/reacting atmosphere up to 400 °C without any observable aggregation of single atoms. A pathway is thus provided to decouple the hydrogenation activity and stability of single‐atom catalysts. Abstract Single‐atom catalysts (SACs) have shown superior activity and/or selectivity...
Article
Single‐atom catalysts (SACs) have shown superior activity and/or selectivity for many energy‐ and environment‐related reactions, but their stability at high site density and under reducing atmosphere remains unresolved. Herein, we elucidate the intrinsic driving force of palladium single atom with high site density (up to 5 wt%) under reducing atmo...
Article
Metal‐organic frameworks (MOFs) and covalent organic frameworks (COFs) attracted enormous attention in recent years. Recently, MOF@COF are emerging as hybrid architectures combining the unique features of the individual components to enable the generation of materials displaying novel physicochemical properties. Herein we report an unprecedented us...
Article
The functional porous hybrid material aza‐MOF@COF is synthesised through post‐synthesis modification of MOF@COF‐LZU1 by a cycloaddition‐based aza‐Diels–Alder reaction. The aza‐MOF@COF exhibits high specific capacitance of 20.35 μF cm⁻² and an exceptional stack capacitance of 1.16 F cm⁻³. Abstract Metal–organic frameworks (MOFs) and covalent organi...
Article
In this work, we propose an experimental approach allowing for the identification and the subsequent quantification of nanoparticles crystallographic facets, based on 3D data obtained using Transmission Electron Microscopy (TEM). The particle shape and faceting can be determined using Electron Tomography (ET) combined with High‐Resolution TEM (HR‐T...
Article
Full-text available
Magnetosomes are intracellular magnetic nanocrystals composed of magnetite (Fe3O4) or greigite (Fe3S4), enveloped by a lipid bilayer membrane, produced by magnetotactic bacteria. Because of the stability of these structures in certain environments after cell death and lysis, magnetosome magnetite crystals contribute to the magnetization of sediment...
Article
Full-text available
The high catalytic performance of core–shell nanoparticles is usually attributed to their distinct geometric and electronic structures. Here we reveal a dynamic mechanism that overturns this conventional understanding by a direct environmental transmission electron microscopy visualization coupled with multiple state-of-the-art in situ techniques,...
Article
The clear description of the morphology and location, with respect to the support, of metallic sub-nanometric particles remains a current experimental strenuous challenge in numerous catalytic applications such as naphtha reforming or biomass conversion. High resolution-HAADF-STEM coupled with in situ and tomographic analyses are undertaken on plat...
Article
Nickel(II) hydroxycarbonate colloids were synthesized in water by the reaction of nickel(II) with carbonate in the presence of hexadecyltrimethylammonium bromide. Then, they were dispersed onto SBA-15 affording, after calcination and reduction, a supported 3 wt% nickel(0) catalyst for the dry reforming of methane (DRM). This material, compared to r...
Article
Full-text available
In the field of heterogeneous catalysis, the successful integration of enzymes and inorganic catalysts could pave the way to multifunctional materials which are able to perform advanced cascade reactions. However, such combination is not straightforward, for example in the case of zeolite catalysts for which enzyme immobilization is restricted to t...
Article
Graphene has been the subject of widespread research during the last decade because of its outstanding physical properties which make it an ideal nanoscale material to investigate fundamental properties. Such characteristics promote graphene as a functional material for the emergence of disruptive technologies. Yet, to impact our daily-life product...
Article
Full-text available
Catalytic performance is known to be influenced by several factors, with the catalysts’ surface oxidation state being the most prominent of all. However, in the great majority of industrial heterogeneous catalytic reactions the oxidation state of the active sites is a subject of intense debate. Preferential oxidation of carbon monoxide in hydrogen...
Article
Full-text available
Metal-zeolite nanocomposites are extensively used in heterogeneous catalysis. The small size of zeolite micropores and non-uniform distribution of the metal component within the zeolite structure can severely reduce the efficiency of these catalysts. In this work, we propose a new single-pot synthesis strategy for the design of metal-zeolite nanoco...
Article
The present study reports on the synthesis and characterization of zinc iron oxide ZnFe2O4 magnetic nanoparticles (MNPs) using the co-precipitation method. Particular attention has been paid to study the influence of the pH in the range between 9 and 12 on both structural and magnetic properties of the MNPs. X-ray diffraction analysis shows the pre...
Article
Developing of both effective and stable noble metal nanoparticle (NPs) catalysts with easy catalyst-product recovery is still challenging in the liquid-phase catalytic processes. Here, we report on the synthesis of a hierarchical structured catalyst that consisted of oxygen functionalized graphite felt (OGF) support for liquid-phase processes. The...
Article
Large quantities of high-quality graphene has been produced through a green and up-scalable method based on the exfoliation and dispersion of graphene in a sugar-based wax, by mimicking the Scotch...
Preprint
div> Integrating enzymatic and heterogeneous catalysis can pave the way to new and performing cascade chemical processes. In this perspective, the preparation of bifunctional structures combining both an active inorganic catalyst and an enzyme is a key. However, such combinations are not straightforward, for example in the case of zeolite catalyst...
Article
Full-text available
Carbon dioxide (CO2) hydrogenation to methane (CH4) is a way of great significance from an energy-saving viewpoint that consists in the direct conversion of a natural and abundant waste into a fuel of added value. Its practical exploitation can significantly impact on the control of anthropogenic CO2 emissions into the earth's atmosphere and their...
Article
Full-text available
Nickel-doped ceria nanoparticles (Ni0.1Ce0.9O2−x NPs) were fabricated from Schiff-base complexes and characterized by various microscopic and spectroscopic methods. Clear evidence is provided for incorporation of nickel ions in the ceria lattice in the form of Ni³⁺ species which is considered as the hole trapped state of Ni²⁺. The Ni0.1Ce0.9O2−x NP...
Article
Palladium (Pd) is one of the most popular metal catalysts in chemical industry. Increase of the metal dispersion is an important challenging task which would decrease cost of the processes. Herein we report significant increase of the dispersion of Pd in Pd/Al2O3 catalyst after contact of Pd hydride nanoparticles with hydrogen peroxide. The effect...
Article
The thermal stability of core-shell Pd@SiO2 nanostructures was for the first time directly monitored in the real space by using the in-situ Environmental Transmission Electron Microscopy (E-TEM) at atmospheric pressure coupled with Electron Tomography (ET) realized on the same particles. The core Palladium (Pd) particles, with octahedral or icosahe...
Article
In this work, we investigate the effect of reaction environment and of the in situ formation of iron precursor upon performing thermal decomposition to synthesize iron oxide nanoparticles (IONPs). Spherical IONPs with a spinel Fe3-xO4 structure were synthesized by thermal decomposition of (Fe)2 stearate assisted by oleic acid in octyl ether under a...
Article
This work calls for a paradigm shift in order to change the operational patterns of self‐regulated membranes in response to chemical signals. To this end, the fabrication of a retrofitting material is introduced aimed at developing an innovative generation of porous substrates endowed with symbiotic but fully independent sensing and actuating capab...
Article
We successfully prepared bifunctional catalysts with the distance between metallic and acid sites tuned at the nanometer scale. Sols of beta zeolite nanoparticles were synthesized and mixed in optimized conditions with a γ-AlOOH boehmite suspension in order to yield alumina/zeolite aggregates with a nanometer scale intimacy. The composition of the...
Article
Few layer graphene (FLG) supported structurally flat polygonal and hexagonal iron platelet NPs are prepared by two different high temperature annealing approaches, i.e., under “conventional” and µ-wave assisted heating. Both methods confirm that FLG acts as a template for 2D NPs tailoring, and flat Fe-based NPs with high surface-to-volume ratio are...
Article
Full-text available
Original titania nanocages are fabricated from sacrificial silica/polystyrene tetrapod-like templates. Here are described the template synthesis, titania deposition and nanocage development through polystyrene dissolution and subsequent silica etching. Discussion about the competitive deposition of titania on the biphasic templates is particularly...
Article
Full-text available
This paper focuses on the effect of synthesis conditions on the structure of cobalt-ZSM-5 zeolites, localization, dispersion and reducibility of cobalt species and their catalytic performance in Fischer-Tropsch synthesis. The zeolite catalysts were prepared using carbon nanotubes as sacrificial templates. Addition of pristine carbon nanotubes resul...
Article
Bio-inspired and cost-effective development of highly porous foam-like carbon structure originating from waste fig-fruit raw materials using chemical activation is described. The as-synthesized porous sample exhibits a specific surface area higher than 2000 m2 g−1 and relatively high porosity with ultimately interconnected micro-, meso-, and macrop...
Article
Full-text available
The successful future of 2D materials, which are crucial for accelerating technology development and societal requirements, depends on their efficient preparation in an economical and ecological way. Herein, we present a significant advance in the top-down exfoliation and dispersion method via an aqua colloid approach. We demonstrate that a broad f...
Article
Cobalt particles dispersed on an oxide support form the basis of many important heterogeneous catalysts. Strong interactions between cobalt and the support may lead to irreducible cobalt oxide formation, which is detrimental for the catalytic performance. Therefore, several strategies have been proposed to enhance cobalt reducibility, such as alloy...
Conference Paper
Full-text available
New catalytic materials have been extensively developed since the last decades for application in several research fields including sensors, drug delivery, light-weight/high mechanical strength composites and catalysis. In this presentation, we will discuss about last developments on the use of bio-sourced precursors for the synthesis of a new clas...