Francisco José Maldonado-Hódar

University of Granada | UGR · Department of Inorganic Chemistry

Graphitic carbon nitride (g-C3N4) was synthetized by a one-step thermal method from different N-rich precursors, namely melamine, dicyandiamide, urea, thiourea and cyanamide. The structure, optical and physicochemical properties of g-C3N4 materials were studied by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Ra...

Heterogeneous catalysts based on magnetite nanoparticles, Fe3O4, were prepared by the chemical coprecipitation method using iron (III) chloride as a salt precursor. The physicochemical properties of the nanoparticles were determined by different techniques and the efficiency was evaluated for the degradation of the cytostatic drug, 5-fluorouracil (...

The degradation of organic matter present in olive mill wastewater (OMW) and the recovery of water were studied by the integration of catalytic wet peroxidation (CWPO) and direct contact membrane distillation (DCMD) for the first time. The oxidation step was performed in a fixed–bed reactor (FBR) working in continuous mode (pH0 = 4.0 ± 0.2, 60 °C,...

A series of adsorbents and photocatalysts were developed using agricultural residues (olive stones) as raw materials. Activated carbons (ACs) were synthesized by physical activation and posteriorly, impregnated with TiO2 by a hydrothermal method. Both adsorbents (ACs) and composites (carbon-TiO2) were texturally, morphologically and chemically char...

One of the major keys in the design of new high-performance catalysts is the optimization of the synthesis procedure to tailor the physicochemical properties. In this context, the preparation of catalysts based on porous carbon gels is summarized. The influence of the different synthesis parameters along the preparation of supported or metal-doped...

Iron oxide catalysts supported on activated carbon prepared from olive stones (OSAC–Fe) were used for the catalytic wet peroxide oxidation of refractory polyphenolic solutions and real olive mill wastewater (OMW) in a fixed-bed reactor (FBR). Catalysts were prepared with different precursors and Fe-loadings. The resulting catalysts were essentially...

A resistive sensor based on films of carbon gel-TiO2 nanocomposites prepared with different percentages of TiO2 by a sol-gel process, was developed to determine ammonia gas. A thin film of carbon gel-TiO2 nanocomposites dispersed in poly(vinylidenfluoride) and deposited on glass slides containing silver electrodes are used as NH3 sensor. The resist...

A series of adsorbents was developed by physical (CO 2) and chemical (KOH) activation of two bio-residues: olive stones (OS) and wood from olive tree pruning (OTP). The physicochemical properties of such materials were determined and correlated with their adsorptive performance in the removal of phenolic compounds of olive mill wastewater (OMW). Ad...

Ennoblement of carbon dioxide, particularly the one produced by anaerobic digestion or by biomass combustion, is a motivation to develop novel or improving already existing processes. In this context, an interesting idea is to use carbon dioxide combined together with methane and water. Therefore, bi-reforming of methane (BRM) for syngas production...

A highly efficient methodology for the selective synthesis of nitrogen heterocycles via Friedländer reaction using carbon materials supported ZnO catalysts under the green chemistry domain is presented. The influence of the physicochemical properties of different carbon supports, in particular an activated carbon (AC), multi-walled carbon nanotubes...

Graphitic carbon nitride (g-C3N4) was used to enhance the photocatalytic activity of ZnO nanoparticles for the degradation of 5-fluorouracil (5-FU) cytostatic drug under UV-LED irradiation. CN/ZnO composites were synthetized by an easy one-pot thermal method, varying the g-C3N4 loading, i.e., from 10 to 67 wt% and a post-thermal exfoliation in air....

A supported gold nanoparticle-catalyzed strategy has been utilized to promote a click chemistry reaction for the synthesis of 1,2,3-triazoles via the azide-alkyne cycloaddition (AAC) reaction. While the advent of effective non-copper catalysts (i.e., Ru, Ag, Ir) has demonstrated the catalysis of the AAC reaction, additional robust catalytic systems...

Photocatalysts are often employed as suspended particles (slurries) in batch reactors, and thus a second step is required for catalyst separation from the treated water, limiting its recovery and reuse. Photocatalytic membranes (PMs), in which photocatalyst nanoparticles are deposited or immobilized to enhance their performance, can provide a compl...

Graphene oxide (GO) is used to enhance the photocatalytic activity of ZnO nanoparticles for the degradation of vanillic acid (VA) under simulated solar light and visible-LED (λ > 430 nm). ZnO-GO composites are prepared by a mixing and sonication process with different GO loadings (i.e., from 1.8 to 6.5 wt.%). The materials are extensively character...

This Special Issue was designed based on two complementary principles, both aimed at developing environmentally friendly production processes, in which catalysis plays a leading role [...]

Escherichia coli colonies were grown on different supports for the removal of nitrates from water. A carbon material and different commercial metal oxides, such as SiO2, TiO2 and Al2O3, and their corresponding carbon–metal oxide composites were studied. The physicochemical properties were analyzed by different techniques and the results were correl...

This manuscript is focused on the relationship between sol-gel synthesis processes and the development of new active phases with fitted morphology, porosity and surface chemistry. The influence of the above parameters on the catalytic performance of the prepared materials for the aromatization of n-hexane to benzene is also evaluated. Different ser...

Carbon nanomaterials have demonstrated their potential as adsorbents, self-catalysts, and catalyst supports, to effectively remove pollutants from air and water. These materials possess unique properties, such as inertness, stability in acidic and basic media, and mainly the ability to tune their porosity and surface chemistry. Thus, the hydrophobi...

A by-product of olive mill’s operation (olive stone, OS) was transformed into activated carbon (AC) and used as support to prepare Fe-based catalysts, which were employed on the catalytic wet peroxide oxidation (CWPO) of olive mill wastewater (OMW). Three Fe-impregnation routes were tested: incipient wetness impregnation (IWI), adsorption (Ads), an...

Glucose–carbon hybrids were synthetized with different carbon materials, namely carbon nanotubes, reduced graphene oxide, carbon black and activated carbon by a hydrothermal treatment. These carbon hybrids were used as Pt-supports (1 wt.%) for the furfural (FUR) hydroconversion in the gas phase at mild operating conditions (i.e., P = 1 atm and T =...

Different series of hybrid carbon/TiO2 composites were prepared and used as photocatalysts. To improve the dispersion of the Ti-precursors during the impregnation process, the microcrystalline cellulose (MCC), as a source of carbon, was dissolved in water by treatment with inorganic acids (HNO3 or H3PO4 or mixture) or bases (NaOH/urea). This treatm...

ZrO2-TiO2/C core-shell composites (CTiXZrYs) were synthesized at different Zr-to-Ti ratios by a facile and economical sol-gel approach to obtain highly efficient solar light-responsive photocatalysts. ZrO2-(CZrXs) and TiO2-covered carbon microspheres (CTiXs) were also prepared as reference materials. SEM and TEM images reveal a coverage formed main...

The resorcinol (R)-formaldehyde (F) polymerization was carried out in different experimental conditions to obtain RF/Mo doped carbon xerogels with different morphology, porosity and nature and dispersion of metal. Attractive or repulsive electrostatic interactions were forced in the starting aqueous solution of RF-monomers using different synthesis...

Functionalized graphene derivatives including graphene oxide (GO), reduced graphene oxide (rGO), and heteroatom (nitrogen/sulphur (N/S) or boron (B))-doped graphene were used to synthesize composites with TiO2 (T). The photocatalytic performance of composites was assessed for the degradation of Orange G dye (OG) under simulated solar light. All the...

A series of biochars and activated carbons (ACs) was prepared combining carbonization and physical or chemical activation of cheap and abundant residues of the olive oil industry. These materials were used as Fe-support to develop low-cost catalysts for the heterogeneous Fenton-like oxidation of simulated olive mill wastewater (OMW), the highly pol...

Carbon–Ti nanocomposites were prepared by a controlled two-step method using microcrystalline cellulose as a raw material. The synthesis procedure involves the solubilization of cellulose by an acid treatment (H3PO4 or HNO3) and the impregnation with the Ti precursor followed of a carbonization step at 500 or 800 °C. The type of acid treatment lead...

This chapter provides an overview on the application of cellulose/titania composites for the removal of organic pollutants by heterogeneous photocatalysis. Cellulose is presented to overcome the drawbacks of titania as semiconductor, in particular, a low activity under visible irradiation and a poor quantum efficiency. The coupling of cellulose and...

Vanadium-carbon composites were successfully prepared by sol-gel methods, and their behaviour as NOx-reduction catalysts was tested. Two different synthesis approaches were employed: the distribution of VOx (i) along the carbon matrix and (ii) on the carbon spheres surface. This allows to modify the carbon-VOx interaction and thus, evaluate the rol...

The efficiency of Fenton/Fenton-like processes on the oxidation of organic matter from real olive mill wastewater (OMW) is described. Tests were performed in lab-scale batch reactors and the influence of different operational parameters was evaluated, namely: type of iron salt, effect of pH readjustments during the reaction, reactants addition meth...

This expert volume provides specialized coverage of the current state of the art in carbon gels. Carbon gels represent a promising class of materials with high added value applications and many assets, like the ability to accurately tailor their structure, porosity, and surface composition and easily dope them with numerous species. The ability to...

Nowadays, there is an increasing interest in the development of promising, efficient, and environmentally friendly wastewater treatment technologies. Among them are the advanced oxidation processes (AOPs), in particular, catalytic wet peroxidation (CWPO), assisted or not by radiation. One of the challenges for the industrial application of this pro...

The air and water pollution is a main challenge in the preservation of our planet for the future generations. Pollution is a changing problem, in such a manner that the technology and materials used for decontamination processes should be continuously improved. The two main options to address this goal are based on the optimization of adsorption or...

A novel series of eco-sustainable catalysts developed by supporting CoO nanoparticles on different carbon supports, highly efficient in the synthesis of quinolines and naphthyridines, through the Friedländer condensation, are reported for the first time. Textural properties, dispersion and location of the Co-phase are influenced by the nature of th...

In the present study carbon xerogels are used for the first time to study the fibroblast cell growth. For that, carbon xerogel microspheres are synthesized and thereafter functionalized with carbon nanofibers followed by the 1,3-dipolar cycloaddition of azomethine ylides (the so called “Prato reaction”) or the addition of aryl diazonium salts (the...

Black TiO2 is capable to absorb the entire or part of the visible spectrum improving, a priori, the photoactivity under solar irradiation. Nevertheless, black TiO2 materials have not been able to demonstrate the expected photocatalytic activity in visible light due to the presence of a large number of recombination centers. In addition, high temper...

Resorcinol-formaldehyde aerogel and xerogel were tested as selective adsorbents of hexane isomers under static and dynamic conditions. The aim of this work is to further study the carbon molecular sieve behaviour of some of these samples for linear and branched hydrocarbons separation in gas phase, and the possibility of tuning the adsorptive prope...

Carbon–phosphorus–titanium composites (CPT) were synthesized by Ti-impregnation and carbonization of cellulose. Microcrystalline cellulose used as carbon precursor was initially dissolved by phosphoric acid (H3PO4) to favor the Ti-dispersion and the simultaneous functionalization of the cellulose chains with phosphorus-containing groups, namely pho...

A Pt catalyst supported on activated carbon was prepared and pretreated at different conditions. Both experimental conditions and catalyst characteristics were optimized. The influence of the textural properties of the support on the catalytic performance, based on the study of the internal and external diffusional limitations, is presented. The Pt...

A series of Ni-doped carbon aerogels with different Ni loadings were prepared and extensively characterized from a textural, chemical and electro-chemical point of view. The formation of graphitic clusters on nickel particles was specially analysed by XPS and Raman spectroscopy. Electro-capacitive properties were studied by cyclic voltammetry, chro...

Alternative composite materials with antibacterial activity have been developed by combining the porosity of carbon materials and the antibacterial activity of half sandwich (cymene)Ru-curcumin complexes. Different types of activated carbon were used, from commercial to synthetic and also ones derived from agricultural waste residues (almond shells...

Metal–carbon–carbon nanofibers composites obtained by catalytic pyrolysis of urban plastic residues have been prepared using Fe, Co or Ni as pyrolitic catalysts. The composite materials have been fully characterized from a textural and chemical point of view. The proportion of carbon nanofibers and the final content of carbon phases depend on the u...

Background The aim of this study is to test different supports on which to deposit Au nanoparticles and to determine the most suitable for Orange II (OII) dye degradation by a photo‐assisted wet peroxidation (PWPO) process. The catalysts used (Au‐Fe2O3, Au‐TiO2, Au‐ZnO and Au‐Al2O3) were prepared by the deposition–precipitation method; a reference...

A series of carbon aerogels doped with iron, cobalt and nickel have been prepared. Metal nanoparticles very well dispersed into the carbon matrix catalyze the formation of graphitic clusters around them. Samples with different Ni content are obtained to test the influence of the metal loading. All aerogels have been characterized to analyze their t...

A series of Mo-doped carbon xerogels were obtained by surfactant-assisted sol-gel polymerization of resorcinol-formaldehyde at neutral pH. The morphology, porous texture, acid-base character and metal phase and dispersion, of these novel nanostructured materials were studied by several and complementary techniques, while their catalytic performance...

Different types of carbon-iron electro-catalysts have been prepared, exhaustively characterized, and tested as cathodes for the electro-catalytic reduction of CO2 at atmospheric pressure. Commercial iron and graphite sheets have also been tested as cathodes for comparison. All these electro-catalysts promoted the formation of C1 to C4 hydrocarbons...

This work presents for the first time a comprehensive analysis of the influence of the textural and elemental properties of different carbonaceous materials on the 5-Fluorouracil (5-FU) removal efficacy from water by adsorption. A detailed textural and elemental characterization of the adsorbent materials was performed, based on which their kinetic...

A carbon xerogel obtained by carbonization of a resorcinol–formaldehyde polymer which was synthesized using Cs2CO3 as catalyst was employed as CO2 selective adsorbent for biogas upgrading. The material presented a large narrow micropore volume (W0(CO2) = 0.34 cm³ g⁻¹) and macropore volume; as expected for a carbon xerogel, these macropores are very...

We report herein different series of new zero valent Cobalt nanocarbons, as doped and supported aerogels, able to efficiently catalyze the reaction of 2-amino-5-chlorobenzaldehyde and β-ketoesters, via Friedländer reaction. The reaction works under solvent-free and mild conditions affording yields over 80% in only 30 min of reaction time. The catal...

A series of a carbon xerogel doped with different percentages of TiO2 has been explored as a tentative via to prepare electrodes for supercapacitors. Carbon composites were obtained by an inverse emulsion method in n-heptane and after carbonization at 900 °C the metal oxide phase is well dispersed on the carbon phase, with a crystal size smaller th...

Carbon xerogel-ZrO2 composites (CZrX) were successfully synthesized through a one-pot sol-gel synthesis. The XRD results confirm the presence of well dispersed (<4.5 nm) cubic ZrO2 on the carbon support, homogeneously distributed on the carbon surface. Gas adsorption and mercury porosimetry measurement pointed out that the increase of ZrO2 in the c...

Revalorization of an agricultural waste from olive oil industry was performed by transforming it into activated carbon. In such a way, a material with excellent textural properties (high surface area and large micro and mesopore volumes) was obtained by carbonization and chemical activation of solid residues from olive oil industry. Moreover, this...

Mesoporous carbon-ZrO2 composites (CZrX) were successfully synthesized by a direct sol-gel procedure. A large battery of experimental techniques is applied for sample characterization. ZrO2 nanoparticles were homogeneously distributed on the carbon supports and stabilized in the cubic phase. The interactions between organic-inorganic phases determi...

The novel coordination polymers M(Me2BPZ) (M = Co, Zn; H2Me2BPZ = 3,3’-dimethyl-1H,1’H-4,4’-bipyrazole), M(H2Me2BPZ)(CH3COO)2(H2O)2 (M = Co, Ni), and Cu(H2Me2BPZ)(Cl)2 were isolated along conventional or solvothermal routes. Their crystal structure was unveiled by powder X-ray diffraction (PXRD), while their thermal stability was assessed by coupli...

The present work aims to explore the impact of the support (MxOy: Al2O3, TiO2, Fe2O3, CeO2, ZnO) on the CO2 hydrogenation activity of supported gold nanoparticles (Au/MxOy) at atmospheric pressure. The textural, redox and surface properties of Au/MxOy catalysts were evaluated by various characterisation methods, namely N2 adsorption-desorption at −...

Carbon aerogels doped with transition metals are found to be efficient and reused catalysts involved in the selective synthesis of quinolines. Interestingly, we report herein the first aldol-based reactions, particularly the Friedländer reaction, catalyzed by zero-valent metal nanoparticles, the activity of the samples being mainly related with the...

The Cover shows a Co⁰-doped carbon aerogel that can efficiently catalyze the Friedländer reaction to produce quinolines.In their Full Paper, M. Godino-Ojer et al. demonstrate that although the carbon matrix contributes to a certain extent to the catalytic performance, the predominant active catalytic species are the zero-valent transition-metal nan...

The Cover shows an industrial landscape, where Au nanoparticles are used as catalysts for oxidation reactions.In their Full Paper, L. M. D. R. de Sousa Martins et al. demonstrate an efficient single-pot oxidative functionalization of cyclohexane and benzyl and methylbenzyl alcohols under mild conditions with high selectivity, catalyzed by reusable...

The degradation of Orange II was evaluated by wet peroxide oxidation using gold nanoparticles supported on Fe2O3, TiO2, ZnO and Al2O3 as catalysts, in a slurry batch reactor. Materials were prepared by the same deposition-precipitation method, which yielded well-dispersed nanosized gold particles (2.2 to 5.5 nm). A commercial catalyst (Au/Fe2O3 sup...

An activated carbon from commercial pine wood pellets was obtained by means of physical activation with carbon dioxide. Carbonized sample was also prepared in order to compare both samples. Carbonization lead to a material with very low micropore volume, which was increased when physical activation was performed (W0(N2) from 0.00 to 0.22 cm³ g⁻¹ an...

Activated carbons from a mixture of olive-residue, oil and vegetable water, known as alperujo, OR, were prepared by KOH and H3PO4 activation. KOH activations were made following two different methods (carbonization-activation and impregnation-activation) with two different KOH/carbon ratios. Textural characterization with N2 and CO2 reveals that a...

Two original series of carbon gels doped with different cobalt loadings and well-developed mesoporosity, aerogels and xerogels, have been prepared, exhaustively characterized, and tested as cathodes for the electro-catalytic reduction of CO2 to hydrocarbons at atmospheric pressure. Commercial cobalt and graphite sheets have also been tested as cath...

The aim of this work is to explore the influence of the support () on the physicochemical characteristics and the N 2 O decomposition (deN 2 O) performance of supported gold nanoparticles (Au/M x O y). Both the bare oxides and the Au/oxide catalysts were characterized by several methods (BET, XRD, SEM, HR-TEM, XPS and H 2-TPR) and comparatively eva...

We report herein an experimental and theoretical study of the Friedlander reaction, from 2-amino-5-chlorobenzaldehyde and ethyl acetoacetate, catalyzed by free-metal nanocatalysts based on carbon aerogels, to afford quinoline 3a. The developed methodology implies the combined use of carbon aerogels with solvent-free technologies under MW irradiatio...

This paper reports on the single-pot efficient oxidative functionalization of alkanes and alcohols, under mild conditions, catalysed by Au nanoparticles supported on Al2O3, Fe2O3, ZnO and TiO2. The obtained materials were tested for cyclohexane oxidation under mild conditions (60ºC, atmospheric pressure), using an environmentally friendly oxidant (...