The electrical behaviour of ultrafine bismuth phosphate particles under a range of temperature and frequency conditions

Organic-molecule-stabilized ultrafine bismuth phosphate was synthesized by applying a wet chemical complexation-mediated route. Structural analysis confirmed the formation of monoclinic-phase nanoparticles made up of four-coordinated PO₄ tetrahedral and eight-coordinated BiO₈ polyhedral units. The dielectric, electrical conductivity, and impedance behaviour of the synthesized material was investigated under a wide range of frequency and temperature conditions. An alternating current conductivity study confirmed that the conduction process was followed by small and large polaron tunnelling mechanisms. An electric field-induced polarization study showed the formation of a hysteresis loop, generated as a result of the strong dipolar interactions through the Bi^δ+-O^δ--type covalent bonds.

Fabrication of 1D/2D BiPO4/g-C3N4 heterostructured photocatalyst with enhanced photocatalytic efficiency for NO removal

The visible light photocatalytic removal of NO in air is a promising way. BiPO₄ is restricted by its wide band gap and can only be responded to ultraviolet light. Herein, 1D BiPO₄ nanorod/2D g-C₃N₄ heterostructured photocatalyst was successfully synthesized via a facile one-step hydrothermal process for efficient visible light photocatalytic removal of NO. With simulated sunlight irradiation, the photocatalytic NO removal activity of the BiPO₄/g-C₃N₄ (64%) is much higher than that of the pure BiPO₄ (7.2%) and g-C₃N₄ (50%). Its excellent photocatalytic performance was ascribed to broadening the light response range to visible light and boosting the separation and transfer of photogenerated electrons and holes. The NO photocatalytic removal mechanism was proposed by the free radical trapping experiment and in situ DRIFTS research. The present study might induce a new means to design BiPO₄-based heterostructured photocatalysts for the removal of NO from air pollution under simulated solar light irradiation.

Synthesis of novel porphyrin derivatives and their self-assemblies to enhance photocatalytic performance

Preparation of new porphyrin derivatives and their self-assemblies to improve photocatalytic performance.

Wide spectral degradation of Norfloxacin by Ag@BiPO4/BiOBr/BiFeO3 nano-assembly: Elucidating the photocatalytic mechanism under different light sources

Metallic Ag deposited BiPO₄/BiOBr/BiFeO₃ ternary nano-hetero-structures were rationally designed and synthesized by a simple precipitation-wet impregnation-photo deposition method. The plasmonic junction possesses an excellent wide spectrum photo-response and makes best use of BiPO₄ which is otherwise a poor photocatalyst. Ag@BiPO₄/BiOBr/BiFeO₃ showed superior photocatalytic activity for degradation of norfloxacin (NFN) under visible, ultra-violet, near-infra-red and natural solar light. Especially catalyst APBF-3 (0.3 wt% Ag@BiPO₄/BiOBr/BiFeO₃) shows 98.1% degradation of NFN (20 mg/L) in 90 min under visible light and 99.1% in less than 45 min under UV exposure. Free radical scavenging experiments and electron spin resonance (ESR) results has been used for explanation of charge transfer, photocatalytic mechanism and role of radicals for binary, ternary and Ag deposited ternary junctions for UV and visible exposure. Metallic Ag in addition to its surface plasmon resonance helps in protection of high conduction band and valence band in the three semiconductors. A dual Z-scheme mechanism has been predicted by comparing with possibilities of double charge and vectorial charge transfer.

Visible-light photocatalytic capability and the mechanism investigation of a novel PANI/Sn3O4 p–n heterostructure

A novel polyaniline (PANI)/Sn₃O₄ heterojunction composed of PANI nanofibers and Sn₃O₄ nanosheets was fabricated by a facile physical milling technique. Modification of Sn₃O₄ with a PANI conductive polymer contributes to facilitating interfacial charge transfer efficiency, and thus, significantly enhances the visible-light Rhodamine B (RhB) photo-degradation. Results indicate that PANI/Sn₃O₄ heterostructures with 10 wt% PANI reached the maximum degradation efficiency (around 97%) for RhB within 5 h, which is 2.27 times higher than that of Sn₃O₄ alone. This improvement is due to the p–n heterostructure formation in PANI/Sn₃O₄. Moreover, the outcome of reactive species capturing experiments demonstrated that in PANI/Sn₃O₄, holes made the largest contribution to RhB degradation under visible light illumination, while hydroxyl radicals showed less significance under the same conditions. In addition, the photocatalytic mechanism was proposed based on evidence from the reactive species test and energy band structure analysis.

A novel polyaniline (PANI)/Sn₃O₄ heterojunction composed of PANI nanofibers and Sn₃O₄ nanosheets was fabricated by a facile physical milling technique.

pH-Controlled photocatalytic abatement of RhB by an FeWO4/BiPO4 p–n heterojunction under visible light irradiation

The novel FeWO₄/BiPO₄ heterojunction generates an inner electric field to promote electron–hole separation efficiency and is a proficient photocatalyst.

Synthesis of a BiOCl1−xBrx@AgBr heterostructure with enhanced photocatalytic activity under visible light

We present a facile approach to preparing a BiOCl_1−xBr_x@AgBr heterostructure using a two-step solvothermal method. Multiple characterisation techniques have been employed to investigate its morphology, structure, optical and electronic properties and photocatalytic performance. The photocatalytic activity of the BiOCl_1−xBr_x@AgBr heterostructure was sufficiently evaluated by adopting Reactive Blue KN-R as the target organic pollutant under visible light irradiation. The as-prepared BiOCl_1−xBr_x@AgBr exhibited much higher photocatalytic activity than BiOCl_1−xBr_x and BiOCl, which was ascribed to the movement of photogenerated electrons from AgBr to BiOCl_1−xBr_x, resulting in effective charge separation and transfer. Moreover, the modification of BiOCl_1−xBr_x with AgBr broadened the light absorption range, making the composite suitable for visible light excitation. The excellent photocatalytic performance provides potential opportunities to utilize BiOCl_1−xBr_x@AgBr for environmental purification and organic pollution treatment of water.

BiOCl_1−xBr_x nanosheets are covered by a thin layer of AgBr that forms BiOCl_1−xBr_x@AgBr heterostucture with high photocatalytic activity.