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The photoelectrocatalytic (PEC) oxidation of 3-pyridinemethanol to 3-pyridinemethanal and vitamin B3 was investigated by using Pt, Au and Pd loaded (as single or bimetallic) nanotube structured TiO2 on Ti plate in water under UVA irradiation. Nanotube structured TiO2 on Ti plate samples were prepared as anode by anodic oxidation method in ethylene glycol solution in different times, and then they were calcined at 500 °C to be obtained in crystalline form. The anodes were loaded with noble metals by electrochemical reduction method and characterized by XRD, XPS, SEM, and photocurrent techniques. The TiO2 on the plates was in the anatase phase. The loaded metals were in metallic form and heterogeneously dispersed on the TiO2 surface in different sizes. The results indicate that a high amount of metal loading negatively affected the PEC activity of the metal loaded samples because UVA irradiation inside the nanotubes was inhibited by the presence of the metal. On the contrary, low amount of Pd showed high PEC activity and high product selectivity values with respect to the pristine sample. PEC experiments were also more selective than the photocatalytic ones for vitamin B3 production. Electrocatalytic (EC) and photocatalytic (PC) experiments were also conducted, however no or low activity was obtained, respectively. PEC experiments showed to be more selective than the PC ones for vitamin B3 production.

Porous magnetic nanomaterials have attracted great attention in a variety of applications, particularly in the magnetically targeted and/or controlled release of various species. In this study, a new route was determined to prepare magnetic and mesoporous montmorillonite/magnetite nanocomposites (Mt-Mag NCs). The changes of textural properties of Mt-Mag NCs as a function of the surfactant and silica precursor composition ratios were investigated for the first time. The NCs were then investigated for loading and release performance of 5-Fluorouracil (5-Fu). The NCs, selected for 5-Fu loading and release studies, showed a high surface area about 340.8 m(2)/ g, an average pore diameter of 8.24 nm, and a magnetization saturation of 18.7 emu/g. Interesting new information was also obtained in the method of determining 5-Fu by UV and the method was slightly modified according to obtained results. In vitro release experiments revealed that the NCs showed sustained release profiles of 5-Fu lasting approximately 8 h. Release profiles of 5-Fu from NCs could be fitted by Korsmeyer-Peppas and Hixson kinetics. In vitro cytotoxic study using MCF7 and CRL-4010 cell lines showed that the NCs are good candidates to delivery 5-Fu. Afyon Kocatepe University

Nanotube structured TiO2 on Ti surface were prepared in ethylene glycol (Ti/TiO2NTEG) medium by anodic oxidation method with different times and then the plates were calcinated at different temperatures. Non-nanotube structured Ti/TiO2, prepared by thermal oxidation method, and nanotube structured TiO2 on Ti plate in hydrogen fluoride solution were also prepared for comparison. Pt loaded Ti/TiO2NTEG photoanodes were also prepared by cyclic voltammetry method with different cycles and the optimum loaded Pt amount was determined. Photoanodes were characterized by using X-ray Diffraction (XRD), Scanning Electron Microscopy-Energy-Dispersive X-ray Analysis (SEM-EDX), and photocurrent methods. XRD analyses proved that almost all TiO2 is in anatase phase. SEM analyses show that nanotubes and Pt nanoparticles on nanotube surface are dispersed quite homogeneously. The longest nanotubes were obtained in the ethylene glycol medium and the nanotube length increased by increasing applied anodic oxidation time. In addition, a linear correlation between nanotube length and XRD peak intensity was found. Moreover, SEM-EDX and XRD analyses evidence that Pt nanoparticles on nanotube surface are metallic and in cubic structure. Photoelectrocatalytic degradation of paraquat was performed using the prepared photoanodes. Moreover, electrocatalytic and photocatalytic degradations of paraquat were also investigated for comparison, however lower activities were observed. These results evidence that the photoanodes show a significant synergy for photoelectrocatalytic activity.

Selective photocatalytic oxidation of 3-pyridinemethanol to 3-pyridinemethanal and vitamin B-3 by using pristine and Pt loaded home prepared (HP) rutile and commercial TiO2 photocatalysts, under UV, UV-vis and visible irradiations in water, was performed in friendly environmental conditions. The photocatalysts were characterized by XRD, SEM-EDAX, BET, DRS, XPS and TGA techniques. The influence of pH on reactivity and total selectivity to 3-pyridinemethanal and vitamin B3 was studied. Under very acidic conditions (pH = 2) no or low activity (depending on photocatalyst) was observed, whereas by increasing the pH from 4 to 12 very high total selectivity was achieved. The Pt loading was beneficial for selectivity whereas the reactivity was positively affected only for crystalline HP sample. This last sample showed good activity under visible irradiation, exhibing an about 4 times higher conversion than the other samples. The influence of the position of the benzylic group in pyridine (2-pyridinemethanol and 4-pyridinemethanol) was also studied. The results showed that to synthesize vitamin B3 in green conditions the photocatalyst should be poorly crystalline or Pt loaded. (C) 2016 Elsevier B.V. All rights reserved.

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.

It has been recently reported by Palmisano et al. (2015) [1] that the oxidation of 2-methoxybenzyl alcohol (2-MBA) to 2-methoxybenzaldehyde (2-MBAD) proceeds in water under near-UV light with an unexpected catalytic effect of 2-MBAD. In order to investigate the catalytic role of aldehyde in photolytic oxidation of ortho-substituted benzyl alcohols (OSBAs), reactivity runs were carried out with 2-methylbenzyl alcohol (2-MeBA), 2-nitrobenzyl alcohol (2-NBA), 2-hydroxybenzyl alcohol (2-HBA) and 2-chlorobenzyl alcohol (2-CIBA) in the absence and in the presence of their corresponding aldehyde. None of those alcohols showed a measurable oxidation rate even in the presence of their aldehydes but 2-NBA was oxidised very fast, although no corresponding carbonyl product was obtained. The possible catalytic role of 2-MBAD was investigated for the photolytic oxidation of 4-methoxybenzyl alcohol (4-MBA), 4-nitrobenzyl alcohol (4-NBA), 2-CIBA, 2-HBA, 2-MeBA and ferulic acid (FA). The results showed that 2-MBAD acts as a catalyst only for 4-MBA, 2-HBA and FA. The photocatalytic oxidation of OSBAs in the presence of powdered TiO2 has been also carried out in order to investigate the mutual influences, if any, between homogeneous and heterogeneous processes. The reactivity runs were carried out with TiO2 photocatalyst in water and under near-UV irradiation; a home-prepared (HP) TiO2 sample was used along with Degussa P25. HP catalyst showed the best performance: the 2-MBA half-life time was 5 times smaller and the selectivity to aldehyde 13 times higher than in the presence of Degussa P25. (C) 2016 Elsevier B.V. All rights reserved.

WOS: 000382184900011, PubMed ID: 27506715, Pencil graphite electrodes modified with Co(II), Ni(II), Cu(II) and Fe(II) metallophthalocyaninetetrasulfonates (MePcTSs) were investigated for an electrochemical determination of bisphenol A (BPA). The electrochemical performances of the modified electrodes for different pH values in phosphate and the Britton-Robinson buffers were determined by cyclic voltammetry; the electrode performances were better in the Britton-Robinson buffer. NiPcTS and CoPcTS modifications of the electrodes had remarkable enhancements on their performances. The differential pulse voltammetry parameters for the electrodes were optimized, and we found that the electrochemical response versus the concentration of BPA is linear from 5.0 x 10(-7) to 1.0 x 10(-5) M for the NiPcTS and CoPcTS modified electrodes. The detection limits of these modified electrodes are 2.9 x 10(-7) and 4.3 x 10(-7) M, respectively, and the effects of interfering species are less than 5%. The results show that NiPcTS and CoPcTS modified pencil graphite electrodes could be used for electrochemical determinations of BPA for analytical purposes., Scientific Research Project Council of Afyon Kocatepe University (BAP Project) [11.FEN.BIL.01], The authors thank the Scientific Research Project Council of Afyon Kocatepe University (BAP Project Number: 11.FEN.BIL.01) for financial support and Dr. Justin Beck (Pennsylvania State University) for his useful suggestions.