Multifunctional BiOI/SiO2/Fe3O4@n-Docosane Phase-Change Microcapsules for Waste Heat Recovery and Wastewater Treatment

Waste heat and organic contaminants are significant issues in water pollution, which has caused ecological problems and threatened human health. To provide an effective solution for wastewater recovery, we designed a novel type of multifunctional phase-change microcapsule. This type of microcapsule was synthesized using n-docosane as a core and a SiO₂/Fe₃O₄ composite as a base shell through in situ interfacial polycondensation with the assistance of a Fe₃O₄ nanoparticle as a Pickering emulsion stabilizer, followed by the deposition of BiOI nanosheets on the surface of the SiO₂/Fe₃O₄ composite shell. Benefiting from the n-docosane core, the resultant microcapsules obtained phase-change enthalpies of 46.8-115.7 J/g for absorbing waste heat from wastewater. The deposited BiOI nanosheets promoted photocatalysis for the microcapsules to degrade organic contaminants in wastewater. Owing to the magnetic response of the Fe₃O₄ nanoparticles, the separability and recyclability of the microcapsules were improved significantly by magnetic separation. Moreover, the microcapsules demonstrate outstanding phase-change reversibility, thermal cycling stability, and shape stability due to the tight SiO₂/Fe₃O₄ composite shell. This study provides a promising approach for designing and developing multifunctional phase-change microcapsules for waste heat recovery and wastewater treatment.

Au/MoS2/Ti3C2 composite catalyst for efficient photocatalytic hydrogen evolution

The Au/MoS₂/Ti₃C₂ composite catalyst has efficient photocatalytic hydrogen evolution performance.

Synthesis and enhanced visible light photocatalytic CO2 reduction of BiPO4–BiOBrxI1−x p–n heterojunctions with adjustable energy band

A series of novel BiPO₄–BiOBr_xI_1−x p–n heterojunctions were successfully prepared by a facile solvothermal method. The morphology, structure and optical properties of photocatalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and ultraviolet visible diffuse reflectance spectroscopy. The visible light photocatalytic activities of BiPO₄–BiOBr_xI_1−x heterojunctions were investigated by photocatalytically reducing CO₂. After 4 hours of irradiation, the 5% BiPO₄–BiOBr_0.75I_0.25 heterojunction showed the highest photocatalytic activity with the yields of CO and CH₄ up to 24.9 and 9.4 μmol g_cat⁻¹ respectively. The improved photocatalytic activity may be due to the formation of BiPO₄–BiOBr_xI_1−x p–n heterojunctions which can effectively restrict the recombination rate of the photoexcited charge carriers. Moreover, the energy band structure of BiPO₄–BiOBr_xI_1−x heterojunctions could be easily adjusted by changing the mole ratio of I and Br. The possible mechanism of the enhancement of the photocatalytic performance was also proposed based on experimental and theoretical analysis. The present study may provide a rational strategy to design highly efficient heterojunctions with an adjustable energy band for environmental treatment and energy conversion.

A series of novel BiPO₄–BiOBr_xI_1−x p–n heterojunctions were successfully prepared by a facile solvothermal method.

Biofabricated BiOI with enhanced photocatalytic activity under visible light irradiation

In the recent past, there has been a large-scale utilization of plant extracts for the synthesis of various photocatalysts. The biofabrication technology eliminates the usage of harmful chemicals and serves as an eco-friendly approach for environmental remediation. Herein, a comparative analysis between bismuth oxyiodide synthesized via Azadirachta indica (neem) leaf extract (BiOI-G) and without leaf extract (BiOI-C) has been envisaged. The BiOI-G and BiOI-C samples were characterized by spectral and microscopic techniques, which revealed that the Azadirachta indica assisted BiOI-G attained enhanced features over BiOI-C such as narrower band gap, large surface area, porosity, increased absorption range of visible light and effectual splitting of the photogenerated e--h+ pairs. Benefiting from these enhanced features, BiOI-G degraded methyl orange (MO), rhodamine B (RhB), and benzotriazole (BT) at a significantly higher rate in comparison to BiOI-C. The degradation rate of MO, RhB and BT by BiOI-G was observed to be 1.3, 1.25 and 1.29 times higher in comparison to BiOI-C. Moreover, BiOI-G displayed high stability upto five cycles of the photocatalytic activity, which endow its effectiveness as a highly-efficient green photocatalyst.

A Novel Heterostructure of BiOI Nanosheets Anchored onto MWCNTs with Excellent Visible-Light Photocatalytic Activity

Developing efficient visible-light-driven (VLD) photocatalysts for environmental decontamination has drawn significant attention in recent years. Herein, we have reported a novel heterostructure of multiwalled carbon nanotubes (MWCNTs) coated with BiOI nanosheets as an efficient VLD photocatalyst, which was prepared via a simple solvothermal method. The morphology and structure were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (DRS), and specific surface area measurements. The results showed that BiOI nanosheets were well deposited on MWCNTs. The MWCNTs/BiOI composites exhibited remarkably enhanced photocatalytic activity for the degradation of rhodamine B (RhB), methyl orange (MO), and para-chlorophenol (4-CP) under visible-light, compared with pure BiOI. When the MWCNTs content is 3 wt %, the MWCNTs/BiOI composite (3%M-Bi) achieves the highest activity, which is even higher than that of a mechanical mixture (3 wt % MWCNTs + 97 wt % BiOI). The superior photocatalytic activity is predominantly due to the strong coupling interface between MWCNTs and BiOI, which significantly promotes the efficient electron-hole separation. The photo-induced holes (h⁺) and superoxide radicals (O₂^-) mainly contribute to the photocatalytic degradation of RhB over 3%M-Bi. Therefore, the MWCNTs/BiOI composite is expected to be an efficient VLD photocatalyst for environmental purification.

The synergetic effect of dual co-catalysts on the photocatalytic activity of square-like WO3 with different exposed facets

The controlled, selective deposition of Pt and PbOx dual-cocatalysts on the edged (200) and (020) facets and the main (002) facets of square-like WO₃ nanoplates, respectively, resulted in a remarkable synergetic effect in the photocatalytic performance.

Enhanced photocatalytic activity of BiOI under visible light irradiation by the modification of MoS2

The suitable modification of MoS₂ with 3D hierarchical BiOI could improve the separation efficiency of photogenerated charge carriers.

A novel AgI/BiOIO3 nanohybrid with improved visible-light photocatalytic activity

AgI/BiOIO₃ nanohybrid photocatalysts were prepared by a successive hydrothermal-deposition process. The visible-light-driven AgI/BiOIO₃ showed excellent photocatalytic activity.

Preparation and photocatalytic activity of WO3–MWCNT nanocomposite for degradation of naphthalene under visible light irradiation

Preparation and application of the novel and high performance WO₃–MWCNT photocatalyst for photodegradation of naphthalene under visible light irradiation.