Electronic metal-support interactions (EMSI) describe the electron flow between metal sites and a metal oxide support. It is generally used to follow the mechanism of redox reactions. In this study ...of CuO-CeO
redox, an additional flow of electrons from metallic Cu to surface carbon species is observed via a combination of operando X-ray absorption spectroscopy, synchrotron X-ray powder diffraction, near ambient pressure near edge X-ray absorption fine structure spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy. An electronic metal-support-carbon interaction (EMSCI) is proposed to explain the reaction pathway of CO oxidation. The EMSCI provides a complete picture of the mass and electron flow, which will help predict and improve the catalytic performance in the selective activation of CO
, carbonate, or carbonyl species in C1 chemistry.
Heterogeneous Catalysis In their Research Article on page 14420, Bolun Wang, Feng Ryan Wang et al. propose an electronic metal–support–carbon interaction (EMSCI) to explain the reaction pathway of CO ...oxidation on CuO/CeO2.
Water splitting is a promising technology in the path towards complete renewable energy within the hydrogen economy but overcoming the sluggishness of the oxygen evolution reaction (OER) is a major ...challenge. Iridium-based oxides remain the most attractive materials for the OER under acidic conditions since they offer the combination of activity and stability. Gaining knowledge about how these materials have such an ability is of great interest to develop improved electrocatalysts for the OER. Among the different iridium-based oxides the materials with high concentrations of electron deficient oxygen (O I− ) have been shown to have higher OER activity, however, they also have high dissolution rates, seemingly due to the presence or formation of Ir III species. In contrast, rutile-type IrO 2 , which does not contain Ir III species, has high dissolution resistance but the OER activity remains comparatively low as only low coverages of O I− species are formed under OER. The apparent link between O I− and Ir III species that comes from these observations has yet to be proven. In this work, using ab initio thermodynamics and in situ X-ray photoelectron and absorption spectroscopy we show that the same electrophilic O I− species that appear on Ir-based oxides under OER can be formed on Ir IV+ δ by mild thermal oxidation of rutile-type IrO 2 , without the presence Ir III species.
Water splitting is a promising technology in the path towards complete renewable energy within the hydrogen economy but overcoming the sluggishness of the oxygen evolution reaction (OER) is a major ...challenge. Iridium-based oxides remain the most attractive materials for the OER under acidic conditions since they offer the combination of activity and stability. Gaining knowledge about how these materials have such an ability is of great interest to develop improved electrocatalysts for the OER. Among the different iridium-based oxides the materials with high concentrations of electron deficient oxygen (O
I−
) have been shown to have higher OER activity, however, they also have high dissolution rates, seemingly due to the presence or formation of Ir
III
species. In contrast, rutile-type IrO
2
, which does not contain Ir
III
species, has high dissolution resistance but the OER activity remains comparatively low as only low coverages of O
I−
species are formed under OER. The apparent link between O
I−
and Ir
III
species that comes from these observations has yet to be proven. In this work, using
ab initio
thermodynamics and
in situ
X-ray photoelectron and absorption spectroscopy we show that the same electrophilic O
I−
species that appear on Ir-based oxides under OER can be formed on Ir
IV+
δ
by mild thermal oxidation of rutile-type IrO
2
, without the presence Ir
III
species.
μ
2
-O species shown to be active in OER can be thermally produced on crystalline IrO
2
bound to Ir
IV+
δ
without requiring the presence of Ir
III
, which offers a route to higher-performance stable OER catalysts.
The current interest in research and development of solid electrolytes for battery systems dictates a necessity to evaluate their electrochemical stability in a wide potential range. It is supposed ...that the stability and properties of the interface formed between the electrode and solid electrolyte at the applied potential (the analog of solid electrolyte interphase (SEI) in liquid electrolytes) are of great importance for the battery operation. While the electrochemical techniques can provide the knowledge of a stability window of the solid electrolyte, a direct method, which helps to trace chemical changes, is still missing, due to the difficulty to reach the interface between the solid electrolyte and thick electrode material. In this paper, we propose to use two-layer graphene transferred directly on the solid electrolyte as the electrode transparent for photoelectrons. Such an electrode is thin enough to probe the interface by X-ray photoelectron spectroscopy to trace the occurring chemical changes. To demonstrate this possibility, we have investigated the electrochemical reduction of Li1.5Al0.5Ge1.5(PO4)3 (LAGP) glass-ceramic electrolyte by in situ XPS.
The High-Altitude Water Cherenkov (HAWC) Observatory is sensitive to gamma rays and charged cosmic rays at TeV energies. The detector is still under construction, but data acquisition with the ...partially deployed detector started in 2013. An analysis of the cosmic-ray arrival direction distribution based on 4.9 x 10 super(10) events recorded between 2013 June and 2014 February shows anisotropy at the 10 super(-4) level on angular scales of about 10degrees. The HAWC cosmic-ray sky map exhibits three regions of significantly enhanced cosmic-ray flux; two of these regions were first reported by the Milagro experiment. A third region coincides with an excess recently reported by the ARGO-YBJ experiment. An angular power spectrum analysis of the sky shows that all terms up to l = 15 contribute significantly to the excesses.
Chemosensor technology for trace gases in the air always aims to identify these compounds and then measure their concentrations. For identification, traceable methods are sparse and relate to large ...appliances such as mass spectrometers. We present a new method that uses the alternative traceable measurement of the ionization energies of trace gases in a way that can be miniaturized and energetically tuned. We investigate the achievable performance. Since tunable UV sources are not available for photoionization, we take a detour via impact ionization with electrons, which we generate using the photoelectric effect and bring to sharp, defined energies on a nanoscale in the air. Electron impact ionization is thus possible at air pressures of up to 900 hPa. The sensitivity of the process reaches 1 ppm and is equivalent to that of classic PID. With sharpened energy settings, substance identification is currently possible with an accuracy of 30 meV. We can largely explain the experimental observations with the known quantum mechanical models.
The original version of this article unfortunately contained an error. The authors would like to correct the error with this erratum. In Fig. 5 the process C and B were incorrectly labelled. The ...corrected Fig. 5 with the right labelling is included in this erratum.
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