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Nanotube-structured TiO2 electrodes on Ti plates were formed in ethylene glycol solution by the anodic oxidation method applied for different times and calcined at 500 °C. Different amounts of WO3 were decorated on the nanotube surfaces electrochemically. The electrodes were characterized, and the effects of the nanotube length on the Ti plate, decorated WO3 amount, electrolyte concentration, applied potential, and type of radiation source on the oxidation of 3-methylpyridine were investigated, together with the product distribution/selectivity. In a photoelectrocatalytic system, the vitamin B3 yield increased significantly (ca. 17 fold) under UVA by decorating nanotube-structured TiO2 with WO3, whilst low reaction rates and no products were found under Vis irradiation, as only unselective photolytic reactions occurred. This unexpected result was clarified for the first time in the literature.

In this study, activated carbon production was carried out using chemically activated pomegranate husks, separated as waste of the pomegranate sour sauce products and the methylene blue adsorption test was conducted. The preliminary analyzed pomegranate husk were mixed with KOH at different ratios, 0.5:1, 1:1, 2:1, 3:1 KOH/pomegranate husk and mixtures were carbonized at different temperatures. The obtained activated carbon samples were characterized using BET and SEM analyses and exposed the largest surface area of 900,12 m 2 /g. The effects of different initial concentration, temperature and pH parameters on methylene blue adsorption were investigated during this study. It has been determined that the increase in temperature and initial concentration can increase the adsorption of methylene blue. The previous studies investigating the effects of pH on methylene blue adsorption showed that adsorption of MM (methylene blue) increased at high pH levels, if not significant. Thus, the maximum adsorption of MM (yield of 95 %) was reached at pH 12. In addition, the amounts of MM adsorption increased as tempreature rised from 25 ⁰C to 35 ⁰C and 45 ⁰C. The increase in the initial concentration increased the amount of MM adsorbed by the same amount of adsorbent. It has been determined that the methylene blue adsorption data corresponds to the Langmuir isotherm model.

Photoelectrocatalytic (PEC) synthesis of 2,5-furandicarbaldehyde (FDC) from 5-(hydroxymethyl)-2-furaldehyde (HMF) has been performed in water by using TiO2 films on Ti layer prepared by thermal annealing of Ti (Ti/TiO2) and TiO2 nanotube on Ti (Ti/TiO2NT) prepared by anodic oxidation as photoanodes. The latter ones showed better activity. In order to improve both activity and selectivity, Ti/TiO2NT was loaded with Pt by photoreduction method. 5-Formyl-2-furoic acid (FFA) was also produced by using Pt loaded Ti/TiO2NT photoanodes. The photoanodes were characterised by using XRD, SEM and XPS techniques. Allotropic phase of TiO2 photoanodes was mainly rutile, whereas trace amounts of anatase phase were found in some samples of TiO2 nanotube photoanodes. The distribution of TiO2 nanotubes on Ti are well organised. In addition, primary particle sizes of TiO2 were increased by increasing thermal treatment temperature; however primary particle sizes of TiO2 in Ti/TiO2NT are higher than that of other samples. The photoanode preparation temperature, bias and medium pH were optimised by following PEC HMF oxidation reaction. Photocatalytic and electrocatalytic HMF oxidations were also performed for comparison and negligible activities were observed. Finally efficient Pt loaded Ti/TiO2NT photoanodes were investigated for PEC selective and active FDC (selectivity up to 40%) and FFA (selectivity up to 18%) syntheses in environmental friendly conditions. (C) 2016 Elsevier B.V. All rights reserved.

The easily synthesis of dihydrofuronaphthoquinones and C-alkenylated naphthoquinones has been investigated through the radical oxidative cyclization of 2-hydroxy-1,4-naphthoquinones and thiophene or furan substituted alkenes catalyzed by manganese(III) acetate. The corresponding heteroaryl substituted dihydrofurans and naphthoquinones have been isolated in good yields.

5-(Hydroxymethyl)-2-furaldehyde (HMF) was selectively oxidized to 2,5-furandicarbaldehyde (FDC) in; aqueous medium by using home prepared (HP) anatase, rutile, and brookite TiO2 nanoparticles. HP samples were prepared via a sol-gel method by using TiCl4 as the TiO2 precursor. Commercial TiO2 catalysts were also used for, comparison. All samples were characterized by BET specific surface area, XRD, TGA, and SEM, and the reactivity results showed that HP catalysts are predominantly amorphous and give rise to selectivities toward FDC more than twice that of commercial and well crystallized catalysts.