True and Spectator Intermediates in Catalysis:  The Case of Ethanol Oxidation on Molybdenum Oxide As Observed by in Situ Laser Raman Spectroscopy

Abstract

A high-throughput laser Raman spectrometer is used to detect adsorbed ethoxide species during the catalytic oxidation of ethanol over supported molybdenum oxide at atmospheric pressure. Two different species are observed, a true reaction intermediate and a relatively inert spectator on the surface. Steady-state and dynamic experiments indicate that the reactive species is associated with ModO terminal bonds on the surface, while the spectator is associated with Mo-O-Mo bridging bonds. Deuterium isotopic substitution experiments indicate that the active intermediate is formed in an equilibrated adsorption step, and decomposes by a rate-determining R-C-H bondbreaking step to form acetaldehyde.

A comparative study of the electrochemical deposition of molybdenum oxides thin films on copper and platinum

“…MoO 2 may be used as catalyst for the oxidation of ethanol to acetaldehyde [8], but also as precursor for the preparation of Mo nanofibers. Zach et al [9] reported the synthesis of molybdenum nanofibers, with diameters between 13 nm and 1 m and up to 500 m long, by H 2 reduction at 500 • C of MoO 2 nanofibers electrodeposited.…”

An Efficient Vanadia Supported SrTiO3 Nanocatalyst for the Selective Oxidation of Benzylalcohol to Benzaldehyde

“…Oyama et al. using deuterium isotopic substitution experiments in the oxidation of ethanol to acetaldehyde . In the step 3 nascent hydroxyl group bonded with the titanium cations which recombines with another OH leads to removal of H 2 O and formation of vanadyl oxygen species and the adsorbed benzaldehyde can desorb as a product (step 4) and leaves the catalyst as it is.…”

A New Crystal Phase Molybdate Yb2Mo4O15: The Synthesis and Upconversion Properties

“…Emission bands locating in the violet-blue, green, and red region can be observed (Figure 3 ). Two emission peaks in the region of 520-538 and 542-560 nm, originated from the transition 2 (Figure 4 a), indicating that at least three and two infrared photons have been involved for the emission of each, one violet and red upconversion photon, respectively. However, all of the three emission bands are much weaker than the green emission band as their relatively ineffi cient upconversion processes.…”

“…Molybdenum oxides (MoOx), especially nanocrystalline MoO 3 exhibit attractive catalytic, photochromic and electronic properties, as well as a great potential for various applications. MoO 3 has attracted considerable attention from researchers in the field of catalysts, chemical sensors, solid lubricants, thermoelectric materials, bioscience, and especially in the recent years in electronic device applications such as field emitters, light‐emitting diodes, and photovoltaics . As a hole‐extracting layer, MoO 3 was demonstrated to improve device performance in solar cells due to its favorable electronic and optical properties .…”