Preparation of titanium dioxide/tungsten disulfide composite photocatalysts with enhanced photocatalytic activity under visible light

Xinyan Xiao,Lili Zheng,Weiping Zhang 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.1

Titanium dioxide/tungsten disulfide (TiO2/WS2) composite photocatalysts were fabricated via a one-step hydrothermal synthesis process, using TiCl4 as titanium source and bulk WS2 as sensitizer. The morphology, structure, specific surface area and optical absorption properties of the composite photocatalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), specific surface area analyzer and ultraviolet-visible diffuse reflection spectrum (UV-vis DRS), respectively. The photocatalytic activity of as-prepared photocatalysts was evaluated by the degradation of methyl orange (MO) under illumination of 500W Xenon lamp. The results indicated that TiO2/WS2 composite photocatalysts possessed excellent photocatalytic activity, and ~95% of the degradation rate for MO was reached when molar ratio of WS2 to TiO2 was 0.004 and the irradiation time was 60 min. Moreover, the carrier trapping experiment and fluorescence spectra showed that •O2 − was the key component in the photocatalytic degradation process and O2 was reduced to be •O2 − by the electrons from the conduction band of TiO2 and WS2 for the degradation of MO.

High-stability flexible body motion monitoring sensor based on waterborne polyurethane-coated conductive warp-knitted fabric

Xinyan Yue,Xiaohu Wang,Xiao Han,Jianhan Hong 한국고분자학회 2024 Macromolecular Research Vol.32 No.7

To prepare a high-stability flexible sensor for body motion monitoring, a conductive warp-knitted fabric (CWKF) with a two-bar tricot structure coated with polyaniline(PANI) was prepared by in situ polymerization, and then a waterborne polyurethane-coated conductive warp-knitted fabric (WPU/CWKF) was prepared using a simple dip-and-dry method. The structure and properties of both CWKF and WPU/CWKF were analyzed, their strain-resistance sensing properties were investigated, and their application in body motion monitoring was discussed. The results indicate that conductive treatment of in situ polymerization can give the polyester warp-knitted fabric good electrical conductivity, with a resistivity of approximately 5 Ω cm. After coating with WPU, the resistivity of the WPU/CKWF increased to approximately 40 Ω cm. Both CKWF and WPU/CKWF showed good strain-resistance sensing performance, but CWKF was more sensitive than WPU/CKWF, whereas WPU/CKWF was more stable than CWKF. Both the CWKF and WPU/CKWF sensors could monitor body motion in real time. Similar to their base materials, the CWKF sensor demonstrated a higher sensitivity for human movement monitoring, whereas the WPU/CKWF sensor exhibited higher stability.

Construction of novel Z-scheme BiOI/Bi3O4Br heterojunction with excellent photocatalytic performance by in situ precipitation process

Feihu Zhang,Xinyan Xiao,Yu Xiao,Xia Cheng 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.127 No.-

An innovative 3D flower-like BiOI/Bi3O4Br hierarchical heterostructures complex material was firstlyconstructed via in-situ growth of ultrathin BiOI on Bi3O4Br by a simple precipitation method. Underthe simulated solar-light illumination for 90 min, the optimal 60% BiOI/Bi3O4Br composite displayedthe highest photodegradation rate of 96.4% for RhB, 80.0% for TC and 77.2% for MO. The correspondingapparent rate constants were 0.0314, 0.0167 and 0.0110 min1, which were 8.26, 1.82 and 3.24-timesthan that of Bi3O4Br, 44.86, 11.13 and 2.62-times than that of BiOI. The improved photodegradation activitycould be owing to the following reasons: 1) The 3D hierarchical heterostructures endowed BiOI/Bi3O4Br with tight interfacial contact, which can supply sufficient migration channels for photoinducedcarriers; 2) The Z-scheme charge migrate pathway promoted the segregation of photocarriers whilemaintaining a robust redox ability; 3) The BiOI/Bi3O4Br heterostructures reinforced light absorptionedges more than 600 nm and augmented specific surface areas over 60 m2g1. In addition, the variousphotocatalytic conditions were studied to imitate the degradation process of RhB in the real aqueous system. The radical capture experiments and EPR test attested that h+ and O2played an important part inthe photodegradation of RhB.

Facile Fabrication of Flame-retardant SiO2/APP@PDMS Fabric with Superhydrophobicity for Highly Efficient Oil/Water Separation

Weijing Zhao,Xinyan Xiao,Zhihao Ye 한국섬유공학회 2021 Fibers and polymers Vol.22 No.2

Flame-retardant SiO2/APP@PDMS fabric with superhydrophobicity was prepared via ultrasound-assisted sol-gelmethod and dip-coatings, in which cotton fabric was substantially decorated with amino functionalized SiO2 (SiO2-NH2),ammonium polyphosphate (APP) and polydimethylsiloxane (PDMS). The surface morphology, element composition andfunctional groups were examined by SEM, EDS and ATR-FTIR, respectively. The SiO2/APP@PDMS fabric exhibited selfcleaningproperty to the solid and liquids with water contact angle (WCA) around 154 °, and showed high separationefficiency for n-dodecane (98.5 %) and n-hexane (96 %), which maintained stable after 10 separation cycles. Furthermore,the SiO2/APP@PDMS fabric presented a lower mass loss rate from TGA curve, indicating the improved thermal stability. The synergistic effect of PDMS and APP resulted in the excellent flame-retardant property of the SiO2/APP@PDMS fabric,during which the dense intumescent char layer formed and the fabric extinguished immediately. The SiO2/APP@PDMSfabric with facile fabrication process exhibited potential applications for both oil/water separation and flame-retardant areas.

Enhanced photocatalytic mechanism of Ag₃PO₄ nano-sheets using MS₂ (M = Mo, W)/rGO hybrids as co-catalysts for 4-nitrophenol degradation in water

Zhang, Weiping,Li, Guiying,Wang, Wanjun,Qin, Yaxin,An, Taicheng,Xiao, Xinyan,Choi, Wonyong Elsevier 2018 Applied Catalysis B Vol.232 No.-

<P><B>Abstract</B></P> <P>A chemically modified Ag<SUB>3</SUB>PO<SUB>4</SUB>@MS<SUB>2</SUB>(M = Mo, W)/rGO composite was firstly synthesized via a liquid-exfoliation solvothermal method. The structure, morphology, optical properties and composition were characterized by X-ray diffraction, FT-IR spectroscopy, scanning electron microscopy, UV–vis diffuse reflectance spectra and X-ray photoelectron spectroscopy, respectively. The characterization results indicated that compact structure could be obtained by using this typical method due to in-situ chemical modification, which could also control the sizes of Ag<SUB>3</SUB>PO<SUB>4</SUB> nano-sheets by adding MS<SUB>2</SUB>/rGO hybrids. More importantly, the resultant Ag<SUB>3</SUB>PO<SUB>4</SUB>@MS<SUB>2</SUB>/rGO composite exhibited higher photocatalytic activity and stability toward the degradation of 4-nitrophenol than pure Ag<SUB>3</SUB>PO<SUB>4</SUB> under sunlight irradiation. The stable structure of Ag<SUB>3</SUB>PO<SUB>4</SUB>@MS<SUB>2</SUB>/rGO was closely related with Z-scheme electronic structure and electrical conductivity of MS<SUB>2</SUB>/rGO hybrids, leading to a higher consumption and transfer of photogenerated electrons. However, by controlling the amounts of MS<SUB>2</SUB>/rGO hybrids, more stable but lower photocatalytic activity composites could be obtained. Further analysis found that the holes and O<SUB>2</SUB> <SUP>−</SUP> were the main reactive species involved in the photocatalytic degradation of 4-nitrophenol. In addition, possible photocatalytic degradation pathways of 4-nitrophenol were also proposed based on the identified intermediates. The findings of this work may provide a new method to design efficient composites for photocatalytic degradation of organic pollutants.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ag<SUB>3</SUB>PO<SUB>4</SUB>@MS<SUB>2</SUB>/rGO catalyst was fabricated via a liquid-exfoliation solvothermal method. </LI> <LI> Ag<SUB>3</SUB>PO<SUB>4</SUB>@MS<SUB>2</SUB>/rGO has high photocatalytic activity and stability under sunlight. </LI> <LI> The stability of Ag<SUB>3</SUB>PO<SUB>4</SUB>@MS<SUB>2</SUB>/rGO was due to its rapid transfer of photogenerated e<SUP>−</SUP>. </LI> <LI> h<SUP>+</SUP> and O<SUB>2</SUB> <SUP>−</SUP> were the main RSs in photocatalytic degradation of 4-nitrophenol. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>