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Despite its considerable potential to address energy and environmental challenges, the practical application of photocatalysis is restricted by the limited efficiency of the photocatalysts. This research aims to improve the photocatalytic efficiency of Bi2MoO6 by adjusting the internal electric field within the crystal lattice via Te doping. Te-Bi2MoO6 nanosheets were prepared by a one-step hydrothermal method. Although the band gap energy and the long-range crystal structure are not affected upon doping, Te substitution provides several benefits to the performance of Bi2MoO6. First, the introduction of Te significantly reduces the thickness of the nanosheets, resulting in a larger surface area. Te states are also introduced into the conduction band, thereby increasing the carrier mobility. More importantly, the reduced cell parameters upon doping and the presence of Te in the lattice not only increase the potential difference between Bi–O and Mo-(Te)–O layers in the lattice but also create an asymmetric potential difference. As a result, an internal electric field is enlarged, leading to increased carrier separation. Consequently, 5.0 mol % Te-doped Bi2MoO6 could degrade 99.7% of Rhodamine B in 1 h under visible light, with 6.4 times higher rate constant than pristine Bi2MoO6. Additionally, the doped sample also exhibits about two times enhancement in benzylamine photooxidation (85% conversion vs 39% conversion) while maintaining excellent stability. Thus, this research highlights the efficacy of modulating the internal electric field through chemical modification as a viable strategy for enhancing the performance of photocatalysts. [ABSTRACT FROM AUTHOR]

ABSTRACT We report on the basic properties of zeolite NaY and potassium supported on NaY (K/NaY) assessed by pyrrole-TPD and MBOH transformation. Pyrrole-TPD revealed that impregnation of zeolite NaY with potassium promoted additional adsorption sites for pyrrole compared to parent zeolite. For zeolite with various potassium loadings, pyrrole adsorbed on K/NaY decreased with increased potassium loading. Reduction in pyrrole adsorption could be due to potassium hindering intrinsic basic sites (lattice oxygen), to oxide of potassium occluding in zeolite cavities restricting access for pyrrole, or to K2O reacting with pyrrole to form nondesorbed pyrrolate anions. On MBOH transformation, potassium almost completely suppressed NaY acid sites while K/NaY basicity increased with potassium loading.

Engineering crystal facets have been proved as one of the most promising strategies for promoting photocatalytic performance of titanium dioxide (TiO2). The earlier research in this field focused on trying to obtain as high ratio of the high energy {001} facet as possible, while later found that the co‐existence of facets is more beneficial. However, controlling crystals to expose suitable facet pairs and facet ratios remains challenging. In this work, we not only comprehensively match possible low‐index facets such as {101}‐{001} and {010}‐{001} facet pairs, but also systematically tune their ratios. Moreover, these faceted particles can be directly grown onto the transparent conductive substrate, which can be directly used as a photoanode. So, their intrinsic behaviors can be precisely evaluated without interference from other exogenous factors such as binders, additives, or assembly skills. Various characterization techniques reveal that both the types of facet pairs and the ratios of facets play crucial roles on photocatalytic behaviors, due to the different electron affinity and dissociative adsorption ability of water molecules on a particular facet. Charge transport and surface chemistry have been thoroughly investigated to identify the underlying mechanism. This work sheds light on a material design strategy considering a suitable match of facet pairs for optimizing photocatalytic performance for a wide variety of applications. [ABSTRACT FROM AUTHOR]

The nature of paraquat adsorption is compared between zeolite NaX and NaY which have the same faujasite structure but different Si/Al ratio, namely 1.2 and 2.2, respectively. The adsorption was proposed to occur via ion exchange and expected to increase with Al content. However, NaX had a lower paraquat adsorption capacity than NaY. The bare and paraquat-containing zeolites (PQX and PQY) were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, N2 adsorption–desorption analysis, magic-angle spinning nuclear magnetic resonance (MAS) NMR, and X-ray photoelectron spectroscopy. The presence of adsorbed paraquat was confirmed by Fourier transform infrared spectroscopy. Paraquat adsorbed in supercages of the zeolites resulting in a decrease of surface area and displacement of sodium cations. Results from 23Na MAS NMR and X-ray photoelectron spectroscopy indicated that interaction of sodium ions in the cavity of NaX was stronger than that in NaY, making it less exchangeable with paraquat. [ABSTRACT FROM AUTHOR]

Adsorption of paraquat and pirimiphos-methyl in water was performed on four adsorbents including montmorillonite (Mt), organoclay (TDA-Mt) from intercalation of Mt with tetradecylammonium chloride, and mesoporous Mt from intragallery templating method (with and without Ti addition). The adsorbents were characterized by X-ray diffraction, N2 adsorption-desorption, and transmission electron microscopy. Paraquat adsorption isotherms followed Langmuir model and the adsorption capacity was as follows: TDA-Mt>Mt>mesoporous Ti-Mt>mesoporous Mt. The adsorption mechanism on TDA-Mt and Mt might be via ion exchange. The adsorption on mesoporous samples was on the external surface with negative charge. The presence of Ti enhanced the adsorption capacity. Pirimiphos-methyl adsorbed on negative charge of the external surface of Mt samples. The adsorbed amount increased with the initial concentration due to a strong intermolecular interaction. [ABSTRACT FROM AUTHOR]

An ethanol biosensor based on alcohol dehydrogenase (ADH) attached to Au seeds decorated on magnetic nanoparticles (Fe3O4@Au NPs) is presented. ADH was immobilized on Fe3O4@Au NPs, which were subsequently fixed by a magnet on a carbon paste electrode modified with 5% (m: m) MnO2. Optimum conditions for the amperometric determination of ethanol with the biosensor were as follows: working potential + 0.1 V (vs. Ag/AgCl); supporting electrolyte: 0.1 M phosphate buffer solution at pH 6.8 containing 0.25 mM of the coenzyme (NAD+); working electrode: carbon paste with magnetically attached Fe3O4@Au NPs (0.012 mg⋅cm-2 electrode area) with immobilized alcohol dehydrogenase (120 units per cm² of electrode area). Linearity between signal and concentration was found for the range from 0.1 to 2.0 M ethanol (r² = 0.995) with a detection limit of 0.07 M, a sensitivity of 0.02 µA⋅mM-1⋅cm-2, a reproducibility of 4.0% RSD, and a repeatability of 2.7% RSD. The results for the determination of ethanol in alcoholic beverages showed good agreement with gas chromatography (GC) with recovery of 96.0-108.8%. [ABSTRACT FROM AUTHOR]

Wood of the Lead tree (Leucaena Leucocephala) is pyrolyzed in an Iwasaki kiln to produce charcoal with a graphitic-like structure with a surface area of 329 m2/g. The charcoal is ground into 3 different particle sizes (large, medium, and small) and activated with carbon dioxide to produce activated carbon. The structure, morphology, elemental composition, porosity, and functional groups of the activated carbon samples are compared with the charcoal precursor. The larger particle size of the charcoal gives activated carbon with a larger surface area, up to 609 m2/g. In addition, wood vinegar is collected during the pyrolysis at 3 temperature ranges and extracted by n-hexane, diethyl ether, and ethyl acetate. The compositions depend on the collecting temperature. The main components are ketones, organic acids, furan and pyran derivatives, esters, phenols and derivatives, alcohols, and alkanes. [ABSTRACT FROM AUTHOR]