Speech Title: Advanced Electrode Materials for Solar Energy

Abstract: Ideal electrode materials must possess both high electrical conductivity and large accessible surface area. Among all carbon materials, pristine graphene has the highest conductivity with large surface area. However, without a substrate, graphene sheets can readhere into graphite to lose surface area or crumple three-dimensionally with damaging conductivity. Therefore, it is a challenging task to solve contradiction between high electrical conductivity and large surface area for electrode materials. In the recent years, Prof. Hu’s group has designed several reactions to synthesize 3D porous alkali metals embedded carbon nanomaterials, which possess both high conductivity and large accessible surface area. Furthermore, those novel carbon materials exhibited excellent performance for dye-sensitized solar cells, perovskite solar cells, and other energy devices. Those findings will be discussed in this plenary talk.

 Keywords: Electrode, Alkali metal-embedded Carbon, Solar cells 

 Speech Title: Mechanistic and synthetic aspects of semiconductor photocatalysis

Abstract: Photocatalysis at semiconductor powders has developed into the most advanced field of chemical solar energy utilization. The role of the photocatalyst is at least bifunctional. It enables a proper assembling of substrates through adsorption at the surface-solvent layer and it catalyzes photoinduced, concerted reduction and oxidation reactions with a great variety of donor and acceptor substrates. In the lecture we shall discuss (i) a classification of reaction types, (ii) a general 3-step mechanistic model, and (ii) perspectives for Organic Synthesis and Environmental Chemistry.

Keywords: Photocatalysis; semiconductor powders, visible light

Photocatalytic water splittingover titania modified by metal or metal oxide nanoparticles

Abstract: Photocatalytic is a new alternative for sustainable energy since it involves the absorption of light to produce hydrogen by irradiating oxide semiconductors. The incorporation of metals or metal oxide nanoparticles on the surface of semiconductors as co-catalysts has proved to enhance the photoactivity for the water splitting reaction. A study about the photoactivity of hydrogen by water splitting using Au–MxOy and Au-M nanoparticles deposited on TiO2–P25 will be presented and these results will be compared to the hydrogen production of the corresponding Au and MxOy nanoparticles on TiO2, to evaluate the effect of combining Au with Ag2O, Cu2O, NiO, CoOx or Pd as co-catalysts on TiO2. The materials were characterized by UV–vis diffuse reflectance, TEM, ICP, EDS and XPS. The combinations of Au–Cu2O/TiO2, Au–NiO/TiO2 and Au-Pd/TiO2 effectively increased the hydrogen production obtained by Au/TiO2. The higher photoactivities achieved by Au–Cu2O and Au–Pd nanoparticles deposited on TiO2 were attributed to an enhancement of the electron charge transfer from TiO2 to the Au–MxOy or Au-M systems.

Acknowledgments: To PAPIIT105416, CONACYT-APN 1216 and CONACYT-CONICET 207090 projects.

Keywords: hydrogen, gold, photocatalysis 

Speech Title: Behaviour of Pt/TiO2 Catalysts with Different Morphological and Structural Characteristics in the Photocatalytic Conversion of Ethanol Aqueous Solutions.

Abstract: The photocatalytic H2 production using aqueous solutions containing sacrificial organic reductants is currently a subject of interest. Although the main goal of such process is the H2 production, the simultaneous valorisation of the sacrificial substrate through the production of other useful compounds is an important aspect that merits to be studied. In the present work, we study the influence of the structural and morphological characteristics of porous Pt/TiO2 on their photocatalytic behaviour in the conversion of ethanol(aq). Tailored Pt/TiO2 catalysts with similar Pt metallic sites and different structural and morphological characteristics were studied. A relationship between the mean pore size and the yield of 2,3-butanediol was established, the lower the pore size, the higher the yield of 2,3-butanediol.

Keywords: Renewable H2; Photocatalytic C-C formation; Pt/anatase photocatalyst

Since 2012 he is an Editorial Member of Elsevier's Sustainable Environment Research journal. He has conducted 6 doctoral theses, published 55 peer-reviewed articles in JCR journals, two books and eleven book chapters and 4 patents. In Scopus there are about 1173citations of his articles with an index h = 20.

Speech Title: Environmental applications of coupled systems based on anodic oxidation/photocatalysis using TiO2 modified materials

Abstract: Some approximates on the successful synthesis of Fe-N codoped Titania powders, using Degussa P25, salt of Fe (II), and Urea. Modified Titania-based materials were obtained using SEM, EDS, RAMAN, BET and diffuse reflectance UV-Vis spectroscopy measurements. The doping of TiO2 induced a shift in the absorption threshold towards the UV spectral range, obtaining catalysts with a greater photoactivity than the one of pure Degussa P25. Photocatalytic performance in codoped titania has been proven to be effective that was assessed through the degradation of blue BR aniline solutions via electrochemical oxidation and photocatalytic reaction, whose decolorization was evaluated using UV-Vis spectrophotometry, and concentration using HPLC determinations. Another experience is using TiO2 nanoparticles were electrophoretically deposited onto BDD. Hybrid BDD/TiO2 showed good electrocatalytic behavior of 0.50 M K4[Fe(CN)₆] by cyclic voltammetry. Photoelectrocatalysis of Acid Blue 80 dye with BDD/TiO2 anode upon 75 mA cm-2 UVA illumination (lmax = 365 nm) yielded much faster color removal and degradation than anodic oxidation with BDD or BDD/TiO2 in the dark.

Keywords: TiO2, anodic oxidation, environmental applications

Dr. Vicente leads the group Environmental Heterogeneous Catalysis and new nanostructured materials of IPICYT and serves as Guest editor of Catalysis Today and Hazardous Materials journals.

Speech Title: Photocatalysis as a Tool for Pathogenic Microorganisms Disinfection

Abstract: Microorganisms related to human and plant health included certain bacteria, viruses, fungi and parasites. The infection depends on a complex sequence of biological events involving host, environmental conditions, chemical and physical interactions between the surfaces of the human or plant and the phytopathogenic microorganism. Most of microorganism shows resistance to conventional fungicides. This study proceeds with a concise discussion on assessing the effective inactivation of the phytopathogenic bacteria by means of electronic microscopy (SEM and HRTEM) and monitoring the changes in morphology of the microorganisms during the photocatalytic inactivation with different AgNP loadings using 1D titanate nanotubes. The photocatalytic method presents a non-invasive way to battle infection, practically with no generation of toxic by-products and as an eco-friendly way to control pathogenic microorganisms that could become of relevance in the near future.

Keywords: Pathogenic Microorganisms; Silver-nanotubes, HRTEM and HAADF.

She has supervised 30 BSc students, 10 MSc students and 4 doctorate students. She was awarded the best junior researcher prize (2007) and advanced researcher award (2nd place, 2011) at her current academic institution. She is a member of the System of National Researchers (Mexico) and co-organizer of the Mexico-China Workshop on Renewable Energy and Environment Remediation.

Speech Title: Environmental and Biomedical Applications of Visible Light Active Photocatalytic Materials 

Abstract:
The development of sustainable and reliable technologies for environmental remediation is nowadays of key importance to assure the well-being of living organisms. In the last decades, advanced oxidation processes (AOPs) have shown to be suitable to alleviate this problem. Among the AOPs, heterogeneous photocatalysis is considered as first hand option for environmental remediation. In spite of the many advantages on the use of titanium dioxide (TiO2) and zinc oxide (ZnO) as photocatalytic materials, still several drawbacks limit their large scale implementation. We have been working on the development of visible light active nanostructured photocatalytic materials. Different synthetic strategies have been implemented in order to control the composition, morphology, band gap and size distribution of the materials [1]. With respect to the synthetic pathway, physicochemical properties of the materials are enhanced by using a sol-gel procedure (TiO2) or microwave assisted solvothermal route (ZnO). Iron doped materials suit very well for water purification since small leaching of iron ions renders a combined heterogeneous/homogeneous (Fenton) photocatalytic system [2]. On the other hand, the use of coinage metals for doping of these materials results in enhanced microbicidal activity. Disinfection of water, air and surfaces has been accomplished with the use of these materials. We have demonstrated the disinfection of industrial and/or hospital aqueous effluents after 5 hour of photocatalytic treatment.     Biomedical applications of the materials have also been explored. ZnO@Fe3O4 composites were synthesized and fully characterized. The materials exhibit compatibility and excellent activity to inhibit the growth of biofilms (Helicobacter pylory and Staphyloccocus aureus). The biocompatibility and/or toxicological potential of these materials were evaluated using different model organisms (plants, red blood cells, rats) [3].