A5063197462- Electrocatalysts for Energy Conversion
- Electrochemical Analysis and Applications
- Advanced battery technologies research
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Synthesis and Characterization of Pyrroles
- Multicomponent Synthesis of Heterocycles
- Crystallography and molecular interactions
- Advanced Battery Materials and Technologies
- Copper-based nanomaterials and applications
- Polyoxometalates: Synthesis and Applications
- Synthesis of heterocyclic compounds
- Advanced Sensor and Energy Harvesting Materials
- Electrochemical sensors and biosensors
- Additive Manufacturing and 3D Printing Technologies
- Catalytic Processes in Materials Science
- Synthesis and biological activity
- Child and Adolescent Health
- Semiconductor materials and devices
- Iron oxide chemistry and applications
- Graphene and Nanomaterials Applications
- Electric Vehicles and Infrastructure
- Organometallic Complex Synthesis and Catalysis
- Business, Innovation, and Economy
- Copper Interconnects and Reliability
The University of Texas at El Paso
2023-2024
Universidad de Costa Rica
2011-2023
Freie Universität Berlin
2014-2021
Central Michigan University
2013
Future advances in renewable and sustainable energy require advanced materials based on earth-abundant elements with multifunctional properties. The design the development of cost-effective, robust, high-performance catalysts that can convert oxygen to water, vice versa, is a major challenge conversion storage technology. Here we report cobalt oxide nanochains as for electrochemical evolution reaction (OER) at both alkaline neutral pH, oxidant-driven, photochemical water oxidation various...
Abstract Water oxidation in the neutral pH regime catalyzed by amorphous transition‐metal oxides is of high interest energy science. Crucial determinants electrocatalytic activity were investigated for a cobalt‐based oxide film electrodeposited at various thicknesses on inert electrodes. For water low current densities, turnover frequency (TOF) per cobalt ion bulk material stayed fully constant variation thickness factor 100 (from about 15 nm to 1.5 μm). Thickness changed neither...
The emergence of disordered metal oxides as electrocatalysts for the oxygen evolution reaction and reports amorphization crystalline materials during electrocatalysis reveal a need robust structural models this class materials. Here we apply combination low-temperature X-ray absorption spectroscopy time-resolved in situ spectroelectrochemistry to analyze structure electrochemical properties series iron-cobalt oxides. We identify composition-dependent distribution di-μ-oxo bridged...
Is water oxidation catalyzed at the surface or within bulk volume of solid oxide materials? This question is addressed for cobalt phosphate catalysts deposited on inert electrodes, namely crystallites pakhomovskyite (Co3(PO4)2⋅8 H2O, Pak) and phosphate-containing Co (CoCat). X-ray spectroscopy reveals that oxidizing potentials transform crystalline Pak slowly (5-8 h) but completely into amorphous CoCat. Electrochemical analysis supports high-TOF activity in Pak, whereas its amorphization...
Water oxidation is pivotal in biological photosynthesis, where it catalyzed by a protein-bound metal complex with Mn<sub>4</sub>Ca-oxide core; related synthetic catalysts may become key components non-fossil fuel technologies.
Iron is observed to induce geometric distortions in oxidized nickel oxyhydroxide that activate the material for oxygen evolution reaction.
Understanding the mechanism for electrochemical water oxidation is important development of more efficient catalysts artificial photosynthesis. A basic step proton-coupled electron transfer, which enables accumulation oxidizing equivalents without buildup a charge. We find that substituting deuterium hydrogen resulted in an 87% decrease catalytic activity on Co-based amorphous-oxide at neutral pH, while 16O-to-18O substitution lead to 10% decrease. In situ visible and quasi-in X-ray...
NiFe oxyhydroxides are prime candidates for efficient alkaline water oxidation; their redox chemistry is tracked by X-ray spectroscopy.
Abstract A mild screen‐printing method was developed to coat conductive oxide surfaces (here: fluorine‐doped tin oxide) with micrometer‐thick layers of presynthesized calcium manganese (Ca–birnessite) particles. After optimization steps concerning the printing process and layer thickness, electrodes were obtained that could be used as corrosion‐stable water‐oxidizing anodes at pH 7 yield current densities 1 mA cm −2 an overpotential less than 500 mV. Analyses electrode coatings optimal...
This research presents a simple method to additively manufacture Cone 5 porcelain clay ceramics by using the direct ink-write (DIW) printing technique. DIW has allowed application of extruding highly viscous ceramic materials with relatively high-quality and good mechanical properties, which additionally allows freedom design capability manufacturing complex geometrical shapes. Clay particles were mixed deionized (DI) water at different ratios, where most suitable composition for 3D was...
Abstract Is water oxidation catalyzed at the surface or within bulk volume of solid oxide materials? This question is addressed for cobalt phosphate catalysts deposited on inert electrodes, namely crystallites pakhomovskyite (Co 3 (PO 4 ) 2 ⋅8 H O, Pak) and phosphate‐containing Co (CoCat). X‐ray spectroscopy reveals that oxidizing potentials transform crystalline Pak slowly (5–8 h) but completely into amorphous CoCat. Electrochemical analysis supports high‐TOF activity in Pak, whereas its...
Abstract Water‐oxidizing calcium–manganese oxides, which mimic the inorganic core of biological catalyst, were synthesized and structurally characterized by X‐ray absorption spectroscopy at manganese calcium K edges. The amorphous, birnesite‐type oxides are obtained through a simple protocol that involves electrodeposition followed active‐site creation annealing moderate temperatures. Calcium ions inessential, but tune electrocatalytic properties. For increasing calcium/manganese molar...
We analyze the stability of anodically electrodeposited cobalt hydroxide films during operation as electrocatalysts for water oxidation and show that considerations these are a complex issue concerning multiple distinct phenomena. combine electrochemical analysis with quantitative content using X-ray fluorescence spectroscopy, transient behavior in operando XANES analysis, structural cryogenic absorption spectroscopy to three behavioral regimes exist. Each regime suffers from degree...
Abstract The requirements for beneficial materials restructuring into a higher performance oxygen evolution reaction (OER) electrocatalyst are still largely open question. Here erythrite (Co 3 (AsO 4 ) 2 ·8H O) is used as Co‐based OER to evaluate its catalytic properties during in situ an amorphous catalyst four different electrolytes at pH 7. Using diffraction, microscopy, and spectroscopy, strong effect the behavior observed depending of anions electrolyte. Only carbonate electrolyte can...
Transition metal oxides are promising electrocatalysts for water oxidation, i.e., the oxygen evolution reaction (OER), which is critical in electrochemical production of non-fossil fuels. The involvement oxidation state changes OER electrocatalysis increasingly recognized literature. Tracing these states under operation conditions could provide relevant information performance optimization and development durable catalysts, but further methodical developments needed. Here, we propose a...
Arsenate ions are incorporated in amorphous cobalt oxide catalysts at the periphery of lattice or substituting ions.
Due to their high theoretical volumetric capacity, aluminum–air batteries are an up-and-coming alternative for energy storage in mobile applications. However, there still several problems that need be solved make the technology commercially viable. One of most significant this type battery is self-corrosion alkaline electrolytes. For reason, study, we implemented NH4VO3 and derivatives mixed with carboxymethyl cellulose (CMC) as high-performance anticorrosive additives cells contain...
Recently, the manufacturing of porous polydimethylsiloxane (PDMS) with engineered porosity has gained considerable interest due to its tunable material properties and diverse applications. An innovative approach control PDMS is use transient liquid phase water improve mechanical properties, which been explored in this work. Adjusting ratios deionized precursor during blending subsequent curing processes allows for controlled porosity, yielding emulsion foam tailored properties. The...
Abstract β-Enaminones have been synthesized by the condensation reaction of β-diketones with various anilines in presence a catalytic amount formic acid, mild and highly efficient acid catalyst methanol. These reactions proceed smoothly short times near-quantitative yields. Supplemental materials are available for this article. Go to publisher's online edition Synthetic Communications® view free supplemental file.
Aluminum–air batteries are an up-and-coming alternative for high-energy density storage. However, one of the main drawbacks is self-corrosion aluminum alloys in alkaline electrolytes, where perform best. For that reason, new resistant to corrosion required. Severe plastic deformation (SPD) techniques versatile methodologies result metals with ultrafine microstructure and can be used prepare or modify their microstructure. In this study, 4N-Al (99,99%) Al-2% Fe, Al-3% Mg, Al 1050, 5052, 6063...
Abstract Aluminum‐air batteries are a promising alternative for portable energy storage. However, one of the significant issues in this technology is corrosion aluminum alkaline electrolytes. In study, we explored heteropolyacids (HPAs) H 5 PMo 11 Al 0.5 V O 40 and 6 AlO as possible anti‐corrosive additives Al7475, Al6062, Al5052 commercial alloys. We also investigated properties NH 4 VO 3 ZnO. Concerning HPAs, only combination with showed activity. ZnO did not present Al6062 alloy, while...
Electrochemical and spectroelectrochemical techniques are very important for characterizing energy materials. In the search new sources of renewable energy, water splitting hydrogen production CO2 reduction is attracting significant attention. These applications require efficient durable catalysts a detailed understanding underlying catalytic mechanism. Here, we experimentally study electrodeposited nickel oxide as catalyst electrochemical oxidation by combining UV–vis techniques, with...
A 16 años del gran descubrimiento grafeno los focos de atención vuelven a estar en este material con el reporte su comportamiento superconductor dependiendo apilado sus capas. Sin embargo, nombre durante estos últimos no solo se ha relacionado la superconductividad, sino que sido una diversidad muy amplia aplicaciones, disciplinas diversas, entre las cabe mencionar: materiales opto-electrónicos, electrodos para catálisis, dispositivos tratamiento desechos, biosensores, otros. Esto hecho un...