Francisco Manuel Marquez

University of Turabo / Universidad AGM-Gurabo Campus · School of Natural Sciences and Technology

The present study reports on the fabrication and performance of ammonia sensors based on single-walled carbon nanotubes (SWCNTs) coated with gold nanoparticles (AuNPs). The AuNPs were incorporated onto the SWCNTs using two different methods: sputtering and chemical deposition. The sensors were exposed to controlled concentrations of ammonia at two...

The present study reports on the fabrication and performance of ammonia sensors based on single-walled carbon nanotubes (SWCNTs) coated with gold nanoparticles (AuNPs). The sensors were subjected to controlled concentrations of ammonia at two temperatures, namely 25 oC and 140 oC, and their response was monitored through successive cycles of ammoni...

This study aimed to investigate the photocatalytic performance of diverse zinc oxide catalysts containing gold nanoparticles (AuNPs), molybdenum disulfide (MoS2), and reduced graphene oxide (rGO) toward the degradation of the antibiotics levofloxacin (LFX) and ciprofloxacin (CFX) in aqueous solutions. The obtained results demonstrate that LFX is mo...

November 15th, 2022 was selected as the day where the human population reached the 8 billion mark [1]. This new reality will force the governments around the world to find ways to sustainably produce and secure food, water, and energy for their countries [2-4]. In terms of water, its quality and availability has been a matter of great concern in re...

The photocatalytic hydrogen evolution reaction (HER) by water splitting has been studied, using catalysts based on crystalline TiO2 nanowires (TiO2NWs), which were synthesized by a hydrothermal procedure. This nanomaterial was subsequently modified by incorporating different loadings (1%, 3% and 5%) of gold nanoparticles (AuNPs) on the surface, pre...

The photocatalytic hydrogen evolution reaction (HER) by water splitting has been studied, using catalysts based on TiO2 nanowires (TiO2NWs), which were synthesized by a hydrothermal procedure. This nanomaterial was subsequently modified by incorporating different loadings of gold nanoparticles (AuNPs) on the surface, previously exfoliated MoS2 nano...

The photocatalytic activity of silver-based catalysts containing different amounts of molybdenum disulfide (MoS2; 5, 10 and 20 wt.%) was evaluated by the degradation of the antibiotic ciprofloxacin and the production of hydrogen via water splitting. All the silver (Ag)-based catalysts degraded more than 70% of the antibiotic in 60 min. The catalyst...

The photocatalytic degradation of two quinolone-type antibiotics (ciprofloxacin and levofloxacin) in aqueous solution was studied, using catalysts based on ZnO nanoparticles, which were synthesized by a thermal procedure. The efficiency of ZnO was subsequently optimized by incorporating different co-catalysts of gC3N4, reduced graphene oxide, and n...

Supplementary Information

The photocatalytic degradation of two quinolone-type antibiotics (ciprofloxacin and 17 levofloxacin) in aqueous solution was studied, using catalysts based on ZnO nanoparticles, which 18 were synthesized by a thermal procedure. The efficiency of ZnO was subsequently optimized by 19 incorporating different co-catalysts of gC3N4, reduced graphene oxi...

The photocatalytic degradation of two quinolone-type antibiotics (ciprofloxacin and levofloxacin) in aqueous solution was studied, using catalysts based on ZnO nanoparticles, which were synthesized by a thermal procedure. The efficiency of ZnO was subsequently optimized by incorporating different co-catalysts of gC3N4, reduced graphene oxide and na...

In this paper, we present the physical foundations and the development of the thermodynamic part of a Modelica library with the fundamental components for modeling thermofluid systems. We have chosen Modelica because it is an object-oriented modeling language that allows an elegant design of the library, with a top-down conception that starts from...

At present, the world is at the peak of production of traditional fossil fuels. Much of the resources that humanity has been consuming (oil, coal, and natural gas) are coming to an end. The human being faces a future that must necessarily go through a paradigm shift, which includes a progressive movement towards increasingly less polluting and ener...

At present, the world is at the peak of production of traditional fossil fuels. Much of the resources that humanity has been consuming (oil, coal and natural gas) are coming to an end. The human being faces a future that must necessarily go through a paradigm shift, which includes a progressive movement towards increasingly less polluting and energ...

Different Ag@TiO2 and Ag@ZnO catalysts, with nanowire (NW) structure, were synthesized containing different amounts of silver loading (1, 3, 5, and 10 wt.%) and characterized by FE-SEM, HRTEM, BET, XRD, Raman, XPS, and UV-vis. The photocatalytic activity of the composites was studied by the production of hydrogen via water splitting under UV-vis li...

Different Ag@TiO2 and Ag@ZnO catalysts, with nanowire (NW) structure, were synthesized containing different amounts of silver loading (1, 3, 5, and 10 wt.%) and characterized by FE-SEM, HRTEM, BET, XRD, Raman, XPS, and UV–vis. The photocatalytic activity of the composites was studied by the production of hydrogen via water splitting under UV–vis li...

For some decades, the scientific community has been looking for alternatives to the use of fossil fuels that allow for the planet's sustainable and environmentally-friendly development. To do this, attempts have been made to mimic some processes that occur in nature, among which the photosystem-II stands out, which allows water splitting operating...

For some decades, the scientific community has been looking for alternatives to the use of fossil fuels that allow the planet's sustainable and environmentally friendly development. To do this, attempts have been made to mimic some processes that occur in nature, among which the photosystem-II stands out, which allows water splitting operating with...

For some decades, the scientific community has been looking for alternatives to the use of fossil fuels that allow the planet's sustainable and environmentally friendly development. To do this, attempts have been made to mimic some processes that occur in nature, among which the photosystem-II stands out, which allows water splitting operating with...

Due to the fact that any type of aerospace vessel needs energy, and in the future, this energy must be nuclear and obtained by fusion, not by fission, this paper presents shortly a method by which nuclear fusion can be more easily achieved on an industrial scale. On the other hand, normal aircraft will have to be electrically operated with modern e...

Objective Because of pipelines corrosion, lead (Pb) and copper (Cu) ions could be generated at low levels in tap water leading to a chronic exposure with the potential to affect the neurochemical balance in the organism. Malfunction of dopamine (DA) and serotonin (5-HT) systems are significantly implicated on learning, working memory, attention pro...

Due to the fact that any type of aerospace vessel needs energy, and in the future, this energy must be nuclear and obtained by fusion, not by fission, this paper presents shortly a method by which nuclear fusion can be more easily achieved on an industrial scale. On the other hand, normal aircraft will have to be electrically operated with modern e...

In this article we present the implementation in Modelica language of a library with the fundamental components for modeling a wide variety of multiphysics systems. Modelica is an object-oriented modeling language, which allows to make a simple, systematic and elegant design of the library. The mechanisms of inheritance and composition of Modelica...

Objective: Because of pipelines corrosion, Lead (Pb) and Copper (Cu) ions could be generated at low levels in tap water leading to a chronic exposure with the potential to affect the neurochemical balance in the organism. Malfunction of Dopamine (DA) and Serotonin (5-HT) systems are significantly implicated on learning, working memory, attention pr...

The goal of this research was to obtain high-density single-walled carbon nanotube forests (SWNTs) on conductive substrates for different applications, including field emission. For this, dip-coating was chosen as catalyst deposition method, to subsequently grow SWNTs by Alcohol Catalytic Chemical Vapor Deposition (AC-CVD). Si (100) was chosen as s...

Liquid hydrogen has been the preferred fuel of NASA for the propellant of rockets. Huge amounts of hydrogen are needed in order to send a rocket or a ship to the space. However, most of the hydrogen that is produced these days is derived from fossil fuels. The consequences of using fossil fuels, instead of renewable sources, are devastating to our...

Conclusions q The synthesis of TiO 2 NWs was done in a very simple way using a hydrothermal process. The use of TiO 2 Nanowires are more effective for the photodegradation of rhodamine B (99.39%), than Anatase (94.29%). q Further studies are necessary to understand the mechanisms involved in these processes. Summary The degradation of water sources...

In recent years there has been an increasing interest for using heterogeneous catalysts with potential applications in hydrogen production as new energy vector. In this research, gold nanoparticles and graphene were deposited on TiO2 Nanowires (TiO2 NWs) synthesized by solvothermal method. ü Moreover, TiO2-based materials are of great interest for...

Emissions of carbon dioxide (CO 2) and other greenhouse gases are currently the cause of global warming, and has drawn significant attention as one of the main anthropogenic contributors to climate change. The reduction of carbon emissions could be carried out through the capture and sequestration of CO2, which can eventually be used to obtain fuel...

The exposure of human communities to trace metals through drinking water is a national concern due to the design of distribution systems and regulatory gaps. Lead and copper are two of the principal construction materials of water systems pipes around the world. Corrosion of pipelines liberates small amounts of these metals toxic ions, which could...

Lithium ion batteries (LIBs) are the enabling technology for many of the societal changes that are expected to happen in the following years. Among all the challenges for which LIBs are the key, vehicle electrification is one of the most crucial. Current battery materials cannot provide the required power densities for such applications and therefo...

Lithium ion batteries (LIBs) are the enabling technology for many of the societal changes that are expected to happen in the following years. Among all the challenges for which LIBs are the key, vehicle electrification is one of the most crucial. Current battery materials cannot provide the required power densities for such applications and therefo...

Vertically Aligned Carbon Nanotubes (VA-CNTs) were grown by Chemical Vapor Deposition (CVD) on a silicon substrate with alternating layers of TiN and SiO2. VA-CNTs were exposed to X-ray radiation to study the change in resistivity later. Preliminary results show an increase in the resistivity of CNTs as a function of radiation exposure time, which...

The goal of this research was to obtain high-density single-walled carbon nanotube forests (SWNTs) on conductive substrates for different applications, including field emission. For this, dip-coating was chosen as the catalyst deposition method, to subsequently grow SWNTs by Alcohol Catalytic Chemical Vapor Deposition (AC-CVD). Si (100) was chosen...

Dear Colleagues, Since the beginning of the 1990s, and aer its discovery by Iijima, carbon nanotubes (CNTs) have experienced an extraordinary scientific interest, owing to their exceptional mechanical, electrical and thermal properties. The synthesis procedures described up to now are very varied (chemical vapor deposition, arc-discharge, laser abl...

Procedimiento de obtención de nanohilos de silicio, en ausencia de fuente gaseosa de silicio, sobre diferentes sustratos. La presente invención proporciona un procedimiento de obtención de nanohilos de silicio, con diámetro y longitud homogéneos y controlados, sobre diversos sustratos, entre los cuales se incluyen aquellos sustratos diferentes al s...

In this research, gold nanoparticles and graphene deposited on different titania-based materials (TiO 2 Degussa P-25, and synthesized TiO 2 Nanowires), prepared by chemical reduction with sodium borohydride (NaBH 4), were studied in the photocatalytic hydrogen production reaction. The effect of different parameters, such as gold loading and wavelen...

In order to avoid serious environmental and economic damages from energy use, humans must stop using fossil fuels altogether, as soon as possible. One possible strategy to cut the dependence of fossil fuels and, at the same time, create a new economic force, is to develop a hydrogen based energy economy. A potentially viable way forward is to produ...

Water pollution has emerged as a primary concern in environmental issues due to the consumption of pharmaceuticals and personal care products which are chemical substances resilient to traditional remediation methods. Due to this, photocatalysis has been considered as a promising decontamination method. TiO 2 nanowires (TiO 2 NWs) were synthesized...

Silica nanowires (SiO2NWs) have attracted considerable attention over the last decades due to their diverse properties and broad range of applications. These include the capacity to emit strong blue light, the versatility to be functionalized in order to respond to several targets or their potential use as protective layer against corrosion. In thi...

In recent years there has been an increasing interest for using heterogeneous catalysts with potential applications in hydrogen production as new energy vector. In this research, gold nanoparticles and graphene were deposited on TiO 2 Nanowires (TiO 2 NWs) synthesized by solvothermal method.  Moreover, TiO 2-based materials are of great interest f...

In this research, gold nanoparticles deposited on different titania-based materials (TiO 2 Degussa P-25, and synthesized TiO 2 Nanowires), prepared by chemical reduction with sodium borohydride (NaBH 4), were studied in the photocatalytic hydrogen production reaction. The effect of different parameters, such as gold loading and wavelength irradiati...

Zinc oxide nanoparticles were synthesized using zinc acetate dihydrated as the precursor. The product was successfully characterized by scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy. The photocatalytic activity of the synthesized zinc oxide nanoparticles was determined by measuring the degradation of PBSA in sys...

Organic dyes are some of the most common additives in industrial use, in manufacturing processes and in consumer goods. This widespread use leads to high levels of dyes in waste water and large bodies of water. These waste products contain compounds that can be released into the waste water, poisoning the microbial and marine life, and depleting th...

Currently, energy nonrenewable sources or fossil fuels are used as the major energy resources. Fossil fuels are about 70% sources of primary energy, generating important pollution problems because these fuels contain sulfur and nitrogen compounds which, during combustion, generate sulfur dioxide and various nitrogen oxides. The rise in price and de...

Water pollution has emerged as a primary concern in environmental issues due to the over-consumption of UV-filters specifically in geographical zones such as the Caribbean because of the resilience of these compounds to traditional remediation methods. Photocatalysis, as an advanced oxidation process, has been considered as a promising decontaminat...

The synthesis and characterization of TiO 2 nanowires (TiO 2 NWs) and ZnO nanoparticles (ZnONPs) were studied to determine their catalytic activity for a possible environmental remediation application to the photodegradation of organic pollutants. The TiO 2 NWs and ZnONPs were fully characterized by SEM, XRD and BET measurements. During the catalyt...

During the last few years, magnetic particles have attracted a great attention due to their interesting applications in different fields, including catalysis, information storage, optoelectronics, biomedical applications, bioseparation, magnetic resonance imaging and targeted drug. These materials are characterized by having a large surface area, a...

The synthesized graphene was characterized by different techniques. ü As a preliminary result a single and fine layer of graphene without defects and high purity was synthesized. ü More research work is necessary to develop a more efficient synthesis procedure. One of the main problems in our society is the energy production and storage. Ion-Li bat...

CuO nanorods have been successfully synthesized with size and morphology that have been well controlled during the synthesis procedure. CuO nanorods have been investigated in three catalytic processes: i) Huisgen [3+2] cycloaddition between benzylazide and phenylacetylene; ii) C-N cross coupling of aniline with iodobenzene; iii) oxidation of CO to...

The need of alternative energy sources has recently become a priority. The increasing demand of energy, the alarming increase of greenhouse gases emission and the variability of oil prices, have driven the need for clean and renewable energy. In this situation we find in the sun a great ally, solar PV is on the verge of achieving the price-per-watt...

The synthesis of Au@TiONWs was done in a very simple way. The Au deposit increase the efficiency of the nanowires during the splitting reactions. The structure of the catalyst remain stable after reaction (high reciclability). Further studies are necessary to understand the mechanisms involved in these processes. SUMMARY The surface of the Earth's...

Photocatalytic water splitting with generation of hydrogen is a green process that concerns activity of a semiconductor material under sunlight irradiation and ambient pressure and temperature. This process has been regarded as a promising solution to resolve the global energy and environmental problems. In this research, photocatalytic hydrogen ge...

Ø We present a simple procedure for the synthesis of silicon nanowires (SiNws) Ø Nanowires were synthesized by thermal treatment without any Si gas source Ø A systematic investigation revealed that temperature, catalyst, substrate morphology and substrate coatings are critical for the growth of SiNws Ø SiNws (diameters~ 30 nm, micrometers lengths)...