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BiVO4 with suitable band edges and a small band gap is considered an efficient photocatalyst for the oxygen evolution reaction (OER), but short charge-transfer lengths limit its photocatalytic ability. Increasing active sites can essentially enhance oxidation reactions and photocatalytic ability. The alkaline etching technique can refine the surface properties of BiVO4 by introducing oxygen vacancies and possibly establishing a heterojunction, but suitable alkaline etching methods are rarely discussed. In this study, three alkaline etching methods, including hydrothermal, soaking, and electrodeposition processes, are first applied for a constant duration to tailor the surface properties of BiVO4 as a photocatalyst for the OER. Alkaline-etched BiVO4 prepared using hydrothermal and soaking processes shows better photocatalytic abilities due to the generation of additional oxygen vacancies, while poor photocatalytic ability is found for that fabricated using electrodeposition due to the formation of less photocatalytic VO2. The highest photocurrent density of 2.38 mA cm−2 is obtained at 1.23 V versus a reversible hydrogen electrode in an electrolyte without a hole scavenger for the BiVO4 etched in the hydrothermal process, while the untreated BiVO4 presents a photocurrent density of 0.58 mA cm−2. A photocurrent retention of 92.3% is achieved after 5000 seconds of continuous illumination. The study supplies blueprints for establishing effective alkaline etching methods for enhancing the photocatalytic ability of BiVO4, with the exception of time costs. [ABSTRACT FROM AUTHOR]

A Co-based metal organic framework derivative is considered to be a promising electroactive material for battery and supercapacitor hybrids (BSHs) for energy conservation, owing to the large surface area, high porosity and cobalt compound composition. Cobalt oxide generates numerous redox reactions and transfers abundant electricity during the charge/discharge process due to multiple redox states. A binder-free electrode is promising to reduce fabricating costs and avoid using non-conductive binders. In this work, a new oxidized zeolitic imidazolate framework-67 (O67) is synthesized on Ni foam without a binder at different temperatures as the electroactive material for BSHs for the first time. A unique four-leaf clover (FLC) morphology is obtained for O67, and more FLC is melted at higher oxidation temperatures. The highest specific capacitance (CF) of 221.5 F g−1 at 20 mV s−1 is obtained for the O67 electrode prepared at 350 °C (O67-350), while the unoxidized electrode only presents a CF value of 91.4 F g−1. The BSH is fabricated using an O67-350 electrode and a carbon electrode. At 500 W kg−1, a maximum energy density of 23.1 W h kg−1 is obtained. Also, the CF remains at 65% of the initial value after 5000 cycles. This study initiates new design routes to develop novel zeolitic imidazolate framework-67 derivatives on nickel foam directly as binder-free electrodes. [ABSTRACT FROM AUTHOR]

With the difference in the photosynthesis process between C3- and C4-plants, the 13C/12C stable isotope ratio of ethanol, i.e., δ13C-ethanol, can potentially be a basis for the discrimination of Scotch whiskies derived from different raw materials. This study analyzed 51 authentic single malt Scotch whiskies and 34 authentic blended Scotch whiskies by gas chromatography–combustion–isotope ratio mass spectrometry (GC-C-IRMS) and examined the resulting data by a series of fitting distribution processes. The evaluation result demonstrated that δ13C-ethanol distribution of single malt Scotch whiskies fitted both normal and 3-parameter lognormal distribution. For blended Scotch whiskies, however, the data distribution of δ13C-ethanol conformed with a 3-parameter lognormal distribution rather than a normal one. Moreover, 99.7% of the confidence intervals (CI) of δ13C-ethanol for single malt Scotch whiskies would define between −23.21‰ to −30.07‰ for 3-parameter lognormal distribution, while from −11.19‰ to −28.93‰ for blended Scotch whiskies on the basis of the statistical properties. The simulative adulterated Scotch whiskies using more than 30% C4-derived edible distilled spirits can be effectively discriminated by means of CI of δ13C-ethanol. Since the addition of rectified spirits produced from the C4 plant has been found in some cases of seized Scotch whiskies in Taiwan, establishing a CI of δ13C-ethanol would be valuable for the purpose of Scotch whisky authentication. [ABSTRACT FROM AUTHOR]

BACKGROUND: The aim of this study was to investigate the influence of high‐pressure processing (HPP) on γ‐aminobutyric acid (GABA) content, glutamic acid (Glu) content, glutamate decarboxylase (GAD) activity, growth of Aspergillus fresenii, and accumulated ochratoxin A (OTA) content in coffee beans. RESULTS: The results indicated that coffee beans subjected to HPP at pressures ≥50 MPa for 5 min increased GAD activity and promoted the conversion of Glu to GABA, and showed a significantly doubling of GABA content compared with unprocessed coffee beans. Additionally, investigation of the influence of HPP on A. fresenii growth on coffee beans showed that application ≥400 MPa reduced A. fresenii concentrations to <1 log. Furthermore, during a 50‐day storage period, we observed that a processing pressure of 600 MPa completely inhibited A. fresenii growth, and on day 50 the OTA content of coffee beans subjected to processing pressures of 600 MPa was 0.0066 μg g−1, which was significantly lower than the OTA content of 0.1143 μg g−1 in the control group. CONCLUSION: This study shows that HPP treatment can simultaneously increase GABA content and inhibit the growth of A. fresenii, thereby effectively reducing the production and accumulation of OTA and maintaining the microbiological safety of coffee beans. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]