Appraisal of photoelectrocatalytic oxidation of glucose and production of high value chemicals on nanotube Ti/TiO2 electrode

Abstract

The present work describes an alternative process for glucose oxidation via photoelectrocatalytic technique using Ti/TiO 2 nanotubes as photoanodes. Under optimum experimental conditions, which entailed 10.0 mM glucose in 0.1 M Na 2 SO 4 , pH 6.60, E app = 1.5 V and UV irradiation we were able to convert 78% of glucose following 180 min of photoelectrocatalysis. Out of that, only 28% was, in effect, converted to CO 2 as detected by total organic carbon removal. During the course of the process, a large part of this glucose was found to be transformed into products among them including Arabinose, Arabinitol, 4ketoglicose, glucohexodialdose, Glucone-d-Lactone, 6-deoxiglucose and Gluconic Acid, where this detection was aided by ion-exchange chromatography with amperometric detection and gas chromatography-mass spectra. The results thus essentially demonstrate that photoelectrocatalys can be considered a suitable alternative in fostering glucose conversion, in aqueous medium, to high added value products using a relatively simple and economic method.

Scaling up Photoelectrocatalytic Reactors: A TiO2 Nanotube-Coated Disc Compound Reactor Effectively Degrades Acetaminophen

“…Voltammetric analysis shows an increased current response of the TiO2 nanotube discs when the photoanode is irradiated (Figure 3), which is associated with photogeneration of charge carriers [35][36][37]. Photons delivered from the UV light source to the TiO2 photoanode surface provide the energy required to overcome the band gap (Eg = 3.2 eV) [38,39]. The small overpotential of oxygen evolution with an onset potential of 1.65 V vs Ag/AgCl suggests a low capability for  OH electrogeneration from water oxidation (Equation (5)).…”

“…As supported by above findings, applying a difference of potential synergistically enhanced performance. The h vb + lifetime on the photoanode surface increases because recombination is inhibited (equation 3) [19,39]. Applying a constant cell potential (E cell ) promotes extraction of photo-excited e cb − through an external electrical circuit in an electrochemically-driven process [2].…”

“…Although acetaminophen has a low quantum yield (Φ 253 = 0.006), direct absorption of photons by acetaminophen in solution can explain the slower removal observed at higher pollutant concentration ( Figure 6) [29,39]. Absorption diminishes photon transport efficiency and limits the amount of light reaching the photoelectrode [23,29].…”

Photoelectrocatalytic performance of nanostructured p-n junction NtTiO2/NsCuO electrode in the selective conversion of CO2 to methanol at low bias potentials

“…2b). Self-organized TiO 2 nanotubes prepared using aqueous methodology are coated on Ti plate with an average diameter of 90 nm, wall thickness of 20 nm and medium length of 900 nm [42,43]. Deposits of CuO nanospheres of average size of 39 nm were well-distributed on the nanotube wall, as shown in Fig.…”

“…The OH production was followed by using 0.05 mmol L −1 RNO solution (Sigma-Aldrich, 97%) as bleaching reaction, once RNO is a wellknown OH radical trapping [42]. The RNO decay was monitored by UV-vis spectrophotometry analysis (Agilent, Cary 60) at 440 nm.…”