ACS Phys Chem Au
September 2024
Today, we witness how our scientific ecosystem tries to accommodate a new form of intelligence, artificial intelligence (AI). To make the most of AI in materials science, we need to make the data from computational and laboratory experiments machine-readable, but while that works well for computational experiments, integrating laboratory hardware into a digital workflow seems to be a formidable barrier toward that goal. This paper explores measurement services as a way to lower this barrier.
View Article and Find Full Text PDFNoble metals supported on reducible oxides, like CoO and TiO, exhibit superior activity in many chemical reactions, but the origin of the increased activity is not well understood. To answer this question we studied thin films of CoO supported on an Au(111) single crystal surface as a model for the CO oxidation reaction. We show that three reaction regimes exist in response to chemical and topographic restructuring of the CoO catalyst as a function of reactant gas phase CO/O stoichiometry and temperature.
View Article and Find Full Text PDFThis study investigates the oxidation state of ceria thin films' surface and subsurface under 100 mTorr hydrogen using ambient pressure X-ray photoelectron spectroscopy. We examine the influence of the initial oxidation state and sample temperature (25-450 °C) on the interaction with hydrogen. Our findings reveal that the oxidation state during hydrogen interaction involves a complex interplay between oxidizing hydride formation, reducing thermal reduction, and reducing formation of hydroxyls followed by water desorption.
View Article and Find Full Text PDFIn the search for rational design strategies for oxygen evolution reaction (OER) catalysts, linking the catalyst structure to activity and stability is key. However, highly active catalysts such as IrO and RuO undergo structural changes under OER conditions, and hence, structure-activity-stability relationships need to take into account the operando structure of the catalyst. Under the highly anodic conditions of the oxygen evolution reaction (OER), electrocatalysts are often converted into an active form.
View Article and Find Full Text PDFHigh-entropy materials are an emerging pathway in the development of high-activity (electro)catalysts because of the inherent tunability and coexistence of multiple potential active sites, which may lead to earth-abundant catalyst materials for energy-efficient electrochemical energy storage. In this report, we identify how the multication composition in high-entropy perovskite oxides (HEO) contributes to high catalytic activity for the oxygen evolution reaction (OER), i.e.
View Article and Find Full Text PDFNanoparticle formation by dopant exsolution (migration) from bulk host lattices is a promising approach to generate highly stable nanoparticles with tunable size, shape, and distribution. We investigated Ni dopant migration from strontium titanate (STO) lattices, forming metallic Ni nanoparticles at STO surfaces. scanning probe measurements confirmed the presence of nanoparticles at the H treated surface.
View Article and Find Full Text PDFIridium and ruthenium and their oxides/hydroxides are the best candidates for the oxygen evolution reaction under harsh acidic conditions owing to the low overpotentials observed for Ru- and Ir-based anodes and the high corrosion resistance of Ir-oxides. Herein, by means of cutting edge surface and bulk sensitive X-ray spectroscopy techniques, specifically designed electrode nanofabrication and DFT calculations, we were able to reveal the electronic structure of the active IrO centers (i.e.
View Article and Find Full Text PDFAdoption of proton exchange membrane (PEM) water electrolysis technology on a global level will demand a significant reduction of today's iridium loadings in the anode catalyst layers of PEM electrolyzers. However, new catalyst and electrode designs with reduced Ir content have been suffering from limited stability caused by (electro)chemical degradation. This has remained a serious impediment to a wider commercialization of larger-scale PEM electrolysis technology.
View Article and Find Full Text PDFThe oxygen evolution reaction has an important role in many alternative-energy schemes because it supplies the protons and electrons required for converting renewable electricity into chemical fuels. Electrocatalysts accelerate the reaction by facilitating the required electron transfer, as well as the formation and rupture of chemical bonds. This involvement in fundamentally different processes results in complex electrochemical kinetics that can be challenging to understand and control, and that typically depends exponentially on overpotential.
View Article and Find Full Text PDFElectrochemistry is a promising building block for the global transition to a sustainable energy market. Particularly the electroreduction of CO and the electrolysis of water might be strategic elements for chemical energy conversion. The reactions of interest are inner-sphere reactions, which occur on the surface of the electrode, and the biased interface between the electrode surface and the electrolyte is of central importance to the reactivity of an electrode.
View Article and Find Full Text PDFCommon methods to produce supported catalysts include impregnation, precipitation, and thermal spray techniques. Supported electrocatalysts produced by a novel method for thermal spray deposition were investigated with respect to their structural properties, elemental composition, and electrochemical performance. This was done using electron microscopy, X-ray photoelectron spectroscopy, and cyclic voltammetry.
View Article and Find Full Text PDFThe variation in the morphology and electronic structure of copper during the electroreduction of CO into valuable hydrocarbons and alcohols was revealed by combining surface- and bulk-sensitive X-ray spectroscopies with electrochemical scanning electron microscopy. These experiments proved that the electrified interface surface and near-surface are dominated by reduced copper. The selectivity to the formation of the key C-C bond is enhanced at higher cathodic potentials as a consequence of increased copper metallicity.
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