In Situ Coupling of Ultrasound to Electro- and Photo-Deposition Methods for Materials Synthesis

Abstract

This short review provides the current state-of-the-art of in situ coupling of ultrasound to chemical deposition methods. Synergetic action of ultrasound and light radiation or electrical fields may result in new powerful methodologies, which include sonophotodeposition and sonoelectrodeposition processes. The effect of ultrasound is explained on the basis of different physical mechanisms emerging from cavitation phenomenon. Some possible mechanisms of the interactions between ultrasound and photochemical and electrochemical processes are discussed here. The application of sonophotodeposition and sonoelectrodeposition as green energy sources in the syntheses of different nanomaterials is also reviewed.

A Combined Approach using Sonochemistry and Photocatalysis: How to Apply Sonophotocatalysis for Biomass Conversion?

“…For example, Colmenares et al synthesized nanomaterials through sonophotochemical procedures in order to control the size, morphologya nd nanostructure of new photoactive materials. [65][66][67] Additionally,t hese synthetic procedures showed interesting advantages such as short times of preparation,e nergy-economization, promising nanophotocatalysts with physicochemical properties for biomass valorization processes. [68] The main developed applications are the production of hydrogen by photocatalytic reforming of biomass and productiono fh igh-value molecules (especially sugar-derived platform molecules) from photocatalytic biomass transformations.…”

“…For example, Colmenares et al. synthesized nanomaterials through sonophotochemical procedures in order to control the size, morphology and nanostructure of new photoactive materials . Additionally, these synthetic procedures showed interesting advantages such as short times of preparation, energy‐economization, promising nano‐photocatalysts with physicochemical properties for biomass valorization processes .…”

General and Prospective Views on Oxidation Reactions in Heterogeneous Catalysis

“…Ultrasound and microwave irradiations, ball milling and sonophotodeposition, to name a few strategies, represent innovative technologies to the conventional solid-state, wet chemistry and gas phase synthesis procedures. Many review articles are available in the literature, offering a comprehensive discussion on this subject [57][58][59][60][61]. Here, through a few selected examples, we wish to highlight the advantages of using ultrasound, ball milling, sonophotodeposition and sonoelectrodeposition in the synthesis of solid catalysts (and photocatalysts) for the selective oxidation of alcohols to the corresponding aldehydes or carboxylic acids.…”

“…In this sense, various materials with controlled morphology and composition have been produced by the in situ coupling of ultrasound with chemical (electrochemical and photochemical) deposition methods. The mechanism of sonoelectro-and sonophotodeposition processes is different (electrochemical reactions vs. photoexcitation), but their synergy with sonication is essentially based on the cavitation phenomenon [61]. The resulting enhanced mass transfer is generally seen as the increase of electrochemical current (or current pulses) in the case of the sonoelectrodeposition process, thereby leading to deposits with enhanced mechanical properties and electrocatalytic properties.…”

“…The resulting CdS-TiO 2 NTs electrodes produced a stronger photocurrent coupled to an extended photoresponse under visible light compared to the corresponding electrodes prepared by the electrodeposition method in silent conditions (without ultrasonic irradiation). To date, only a few materials/catalysts have been prepared by the sonophotodeposition method that was implemented by the group of Colmenares [61]. For example, Fe 3+ -based nanoparticles (4-5 nm) were sonophotodeposited on a TiO 2 /zeolite Y support material (ultrasonic horn, 20 kHz, 700 W, 25% amplitude, sun-imitating Xenon lamp, 240-2000 nm) [66].…”