scispace - formally typeset
Search or ask a question
Author

José Luis de la Fuente

Bio: José Luis de la Fuente is an academic researcher from Instituto Nacional de Técnica Aeroespacial. The author has contributed to research in topics: Polymerization & Atom-transfer radical-polymerization. The author has an hindex of 26, co-authored 81 publications receiving 1739 citations. Previous affiliations of José Luis de la Fuente include Norwegian University of Science and Technology & Spanish National Research Council.


Papers
More filters
Journal ArticleDOI
TL;DR: In this article, an application of CO stripping-voltammetry as a diagnostic tool for the determination of surface composition of various PtRu nanoparticles (NPs) was reported, which is useful for assessment of catalyst homogeneity.

112 citations

Journal ArticleDOI
TL;DR: A detailed investigation of the polymerization of glycidyl methacrylate (GMA), an epoxy-functional monomer, by atom transfer radical polymerization (ATRP) was performed as discussed by the authors.
Abstract: Summary: A detailed investigation of the polymerization of glycidyl methacrylate (GMA), an epoxy-functional monomer, by atom transfer radical polymerization (ATRP) was performed. Homopolymers were prepared at relatively low temperatures using ethyl 2-bromoisobutyrate (EBrIB) as the initiator and copper halide (CuX) with N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA) as the catalyst system. The high polymerization rate in the bulk did not permit polymerization control. However, homopolymerization in solution enabled us to explore the effects of different experimental parameters, such as temperature, solvent (toluene vs. diphenyl ether) and initiator concentration, on the controllability of the ATRP process. SEC analysis of the homopolymers synthesized confirmed the importance of solvent character on molecular weight control, the lowest polydispersity indices () and the highest efficiencies being found when the polymerizations were performed in diphenyl ether in combination with a mixed halide technique. A novel poly(glycidyl methacrylate)-block-poly(butyl acrylate) (PGMA-b-PBA) diblock copolymer was prepared through ATRP using PGMA-Cl as a macro-initiator. This chain growth experiment demonstrated a good living character under the conditions employed, while simultaneously indicating a facile synthetic route for this type of functional block copolymer. In addition, the isotacticity parameter for the PGMAs obtained was estimated using 1H NMR analysis which gave a value of σGMA = 0.26 in agreement with that estimated in conventional radical polymerization. SEC chromatograms of PGMA-Cl macroinitiator and PGMA-b-PBA diblock copolymer.

109 citations

Journal ArticleDOI
TL;DR: In this paper, a polyol-based method was used to encapsulate pre-synthesised Ru nanoparticles (NPs) by Pt using polyol without capping agents at various pH values (6, 7, 8 and 10).

58 citations

Journal ArticleDOI
TL;DR: In this article, a detailed investigation of the polymerization of allyl methacrylate, a typical unsymmetrical divinyl compound containing two types of vinyl groups, methaceloyl and allyl, with quite different reactivities, was performed with atom transfer radical polymerization (ATRP).
Abstract: A detailed investigation of the polymerization of allyl methacrylate, a typical unsymmetrical divinyl compound containing two types of vinyl groups, methacryloyl and allyl, with quite different reactivities, was performed with atom transfer radical polymerization (ATRP). Homopolymerizations were carried out in bulk, with ethyl-2-bromoisobutyrate as the initiator and with copper halide (CuX, where X is Cl or Br) with N,N,N',N,N-pentamethyldiethylenetriamine as the catalyst system. Kinetic studies demonstrated that during the early stages of the polymerization, the ATRP process proceeded in a living manner with a low and constant radical concentration. However, as the reaction continued, the increased diffusion resistance restricted the mobility of the catalyst system and interrupted the equilibrium between the growing radicals and dormant species. The obtained poly(allyl methacrylate)s (PAMAs) were characterized with Fourier transform infrared, 1 H NMR, and size exclusion chromatography techniques. The dependence of both the gel point conversion and molecular characteristics of the PAMA prepolymers on different experimental parameters, such as the initiator concentration, polymerization temperature, and type of halide used as the catalyst, was analyzed. These real gel points were compared with the ones calculated according to Gordon's equation under the tentative assumption of equal reactivity for the two types of vinyl groups. Moreover, the microstructure of the prepolymers was the same as that exhibited by those homopolymers prepared by conventional free-radical polymerization; the fraction of syndiotactic arrangements increased as the reaction temperature was lowered.

56 citations

Journal ArticleDOI
TL;DR: The performance of PtCo/C electrocatalysts in the oxygen reduction reaction is enhanced after thermal treatment in hydrogen as discussed by the authors, and the intrinsic activity (per gram of Pt) after the adequate treatment is far superior to that of the commercial sample.
Abstract: The performance of PtCo/C electrocatalysts in the oxygen reduction reaction is enhanced after thermal treatment in hydrogen. In fact, the intrinsic activity (per gram of Pt) of PtCo/C electrocatalyst after the adequate treatment is far superior to that of the commercial sample. The PtCo nanoparticles were prepared from the water-in-oil microemulsion technique. The total metal loading of the catalyst was 30 wt%, and two reduction temperatures, 300 and 875 8C, were studied. Electrochemical measurements were carried out using the rotating disk electrode method in 0.5 M H2SO4 at room temperature, while the Pt real surface area was determined by CO stripping voltammetry. Analyses from XPS and TPR revealed that the amount of Co and Pt reduced species as well as the particle size (XRD), increased with the thermal treatment. Results derived from the electrochemical analyses were in agreement with those obtained in a H2/O2 single cell. These results demonstrate the important role of the cobalt as well as the reduction temperature and atmosphere, and open new ways for the design of improved bimetallic catalyst. # 2007 Elsevier B.V. All rights reserved.

53 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: Catalytic Solvents: Catalyst Disproportionation 4981 2.2.1.
Abstract: 2.1.6. Tacticity and Sequence: Advanced Control 4967 2.2. Transition Metal Catalysts 4967 2.2.1. Overviews of Catalysts 4967 2.2.2. Ruthenium 4967 2.2.3. Copper 4971 2.2.4. Iron 4971 2.2.5. Nickel 4975 2.2.6. Molybdenum 4975 2.2.7. Manganese 4976 2.2.8. Osmium 4976 2.2.9. Cobalt 4976 2.2.10. Other Metals 4976 2.3. Cocatalysts (Additives) 4977 2.3.1. Overview of Cocatalysts 4977 2.3.2. Reducing Agents 4977 2.3.3. Free Radical Initiators 4977 2.3.4. Metal Alkoxides 4977 2.3.5. Amines 4978 2.3.6. Halogen Source 4978 2.4. Initiators 4978 2.4.1. Overview of Initiators: Scope and Design 4978 2.4.2. Alkyl Halides 4978 2.4.3. Arenesulfonyl Halides 4979 2.4.4. N-Chloro Compounds 4979 2.4.5. Halogen-Free Initiators 4979 2.5. Solvents 4980 2.5.1. Overview of Solvents 4980 2.5.2. Catalyst Solubility and Coordination of Solvent 4981 2.5.3. Environmentally Friendly Solvents 4981 2.5.4. Water 4981 2.5.5. Catalytic Solvents: Catalyst Disproportionation 4981

1,131 citations

Journal ArticleDOI
TL;DR: This Review surveys different classes of reactive polymer precursors bearing chemoselective handles and discusses issues related to the preparation of these reactive polymers by direct polymerization of appropriately functionalized monomers as well as the post-polymerization modification of these precursor into functional polymers.
Abstract: Post-polymerization modification is based on the direct polymerization or copolymerization of monomers bearing chemoselective handles that are inert towards the polymerization conditions but can be quantitatively converted in a subsequent step into a broad range of other functional groups. The success of this method is based on the excellent conversions achievable under mild conditions, the excellent functional-group tolerance, and the orthogonality of the post-polymerization modification reactions. This Review surveys different classes of reactive polymer precursors bearing chemoselective handles and discusses issues related to the preparation of these reactive polymers by direct polymerization of appropriately functionalized monomers as well as the post-polymerization modification of these precursors into functional polymers.

733 citations

Journal ArticleDOI
TL;DR: A definition for truly metal-free catalysts is proposed and the differences between NC and M-Nx /C catalysts are discussed to inspire the development of more advanced nonprecious-metal catalysts for the ORR.
Abstract: The notion of metal-free catalysts is used to refer to carbon materials modified with nonmetallic elements. However, some claimed metal-free catalysts are prepared using metal-containing precursors. It is highly contested that metal residues in nitrogen-doped carbon (NC) catalysts play a crucial role in the oxygen reduction reaction (ORR). In an attempt to reconcile divergent views, a definition for truly metal-free catalysts is proposed and the differences between NC and M-Nx /C catalysts are discussed. Metal impurities at levels usually undetectable by techniques such as XPS, XRD, and EDX significantly promote the ORR. Poisoning tests to mask the metal ions reveal the involvement of metal residues as active sites or as modifiers of the electronic structure of the active sites in NC. The unique merits of both M-Nx /C and NC catalysts are discussed to inspire the development of more advanced nonprecious-metal catalysts for the ORR.

562 citations

Journal ArticleDOI
TL;DR: This critical review will summarize recent advances on engineering advanced carbon nanomaterials with different dimensions for the rational design and synthesis of noble-metal-free oxygen reduction electrocatalysts including heteroatom-doped carbon nanmaterials, transition metal-based nanoparticle (NP)-carbon Nanomaterial composites and especially the stable iron carbide (Fe3C)-based NP-carbon nanom material composites.
Abstract: One of the critical issues in the industrial development of fuel cells (e.g., proton exchange membrane fuel cells, direct methanol fuel cells and biofuel cells) is the high cost, serious intermediate tolerance, anode crossover, sluggish kinetics, and poor stability of the platinum (Pt) as the preferred electrocatalysts for the oxygen reduction reaction (ORR) at the cathode. The development of novel noble-metal-free electrocatalysts with low cost, high activity and practical durability for ORR has been considered as one of the most active and competitive fields in chemistry and materials science. In this critical review, we will summarize recent advances on engineering advanced carbon nanomaterials with different dimensions for the rational design and synthesis of noble-metal-free oxygen reduction electrocatalysts including heteroatom-doped carbon nanomaterials, transition metal-based nanoparticle (NP)-carbon nanomaterial composites and especially the stable iron carbide (Fe3C)-based NP-carbon nanomaterial composites. Introducing advanced carbon nanomaterials with high specific surface area and stable structure into the noble-metal-free ORR field has not only led to a maximized electrocatalyst surface area for the electron transfer but also resulted in enhanced electrocatalyst stability for long-term operation. Therefore, the rational design and synthesis of noble-metal-free electrocatalysts based on heteroatoms, transition metal-based NPs and Fe3C-based NP functionalized carbon nanomaterials are of special relevance for their ORR applications, and represents a rapidly growing branch of research. The demonstrated examples in this review will open new directions on designing and optimizing advanced carbon nanomaterials for the development of extremely active and durable earth-abundant cathodic catalysts for fuel cell applications.

558 citations