Journal of Materials Science

Mei, Hao; Jin, Dai; Wang, Jintao; Zhang, Rongbin; Wang, Xuewen

doi: 10.1007/s10853-022-07851-zpmid: N/A

BiOCl is widely considered as a promising photocatalyst and is commonly used in the photodegradation of organic pollutants owing to its unique hierarchical structure, chemical stability, and corrosion resistance. However, its high valence band position and low photogenerated carrier separation efficiency limit its photocatalytic application. Despite the fact that point defects have been demonstrated to efficiently regulate the photocatalytic capacity of semiconductors, only a few studies have explored the potential impact of chlorine vacancies on the photocatalytic performance of BiOCl. In our work, an indirect vacancy construction strategy is developed to obtain Cl-deficient BiOCl1-x. After the introduction of Cl vacancies, the valence band maximum position is promoted from 2.06 eV of the BiOCl0.8I0.2 to 2.89 eV of the BiOCl0.8, significantly improving the photooxidation ability and inhibiting the recombination of photogenerated carriers. Therefore, the Cl-deficient BiOCl1-x exhibits considerably enhanced photodegradation efficiency for organic pollutants, including tetracycline, phenol, methyl orange, and rhodamine B. Furthermore, the potential value of Cl vacancies in enhancing photocatalytic capacity is deeply investigated in this study. Hence, the study is illustrated as a substantial regulating strategy and provides a new method to devise high-activity bismuth oxyhalides through the construction of halogen vacancies.Graphical Abstract[graphic not available: see fulltext]

Cheang, Tuckyun; Zhou, Hongyan; Lin, Weihao; Wang, Yayun; Chang, Xiaonian; Gao, Feng; Zhang, Yongcheng

doi: 10.1007/s10853-022-07865-7pmid: N/A

In recent years, many heavy metal ions have been discharged into the environment, which is threatening human health. Herein, the β-cyclodextrin-modified molybdenum disulfide composite (β-CD/MoS2) was prepared to adsorb Cr(VI) from water. The results demonstrated that the retention of Cr(VI) onto β-CD/MoS2 was dependent on pH and independent of coexisting ions. The removal capacity of β-CD/MoS2 for Cr(VI) reached 156.8 mg/g, and the removal process was endothermic. According to the characterization analysis, the uptake of Cr(VI) onto β-CD/MoS2 was governed by electrostatic attraction. Besides, the oxygen-containing groups were also responsible for the capture of Cr(VI). This work can offer new sight into the uptake of Cr(VI) from the ecological system.

Sirat, Mohamad Shukri; Johari, Muhammad Hilmi; Mohmad, Abdul Rahman; Haniff, Muhammad Aniq Shazni Mohammad; Ani, Mohd Hanafi; Hussin, Mohd Rofei Mat; Mohamed, Mohd Ambri

doi: 10.1007/s10853-022-07873-7pmid: N/A

The distinctive properties of van der Waals heterostructures that combine two or more two-dimensional materials are of interest due to their potential for high-performance devices. Molybdenum disulfide (MoS2)/graphene has been shown as good photodetectors, sensors and field-effect transistors. However, the progress is restricted due to susceptibility of the single-layer MoS2/graphene to the substrate that affects its properties. Recently, few-layer (FL) MoS2 and multilayer (ML) graphene have shown a fairly good electrical performance. Here, a direct growth of FL MoS2 on the ML graphene approach in chemical vapor deposition is taken to synthesize FL MoS2/ML graphene heterostructure. A comprehensive study on the properties of the FL MoS2/ML graphene heterostructure is conducted. The Raman spectra indicate the presence of typical MoS2 peaks (E12g and A1g modes) and graphene peaks (D, G and 2D bands). The slight graphene-peaks shift is related to the electron transfer from ML graphene to the FL MoS2, deducing a good interfacial interaction between both materials. Referring to the atomic force microscopy images, the thickness of the FL MoS2 and ML graphene is measured around 3 nm and 10 nm, respectively. The X-ray diffraction and transmission electron microscope indicate that the grown FL MoS2 is 3R-phase. Field-effect transistor based on the FL MoS2/ML graphene is fabricated and the estimated carrier mobility is around 1036 cm2 V−1 s−1. Our work highlights the necessity of utilizing FL MoS2/ML graphene for extensive fundamental and application studies.

Xu, Yunfei; Zhang, Hongda; Gong, Daming; Chen, Yanxin; Xu, Shouwu; Qiu, Ping

doi: 10.1007/s10853-022-07885-3pmid: N/A

Surface defect engineering has shown to be an effective way to prepare cheap and efficient photoanode. In this study, oxygen vacancies are introduced to the hematite photoanode by a stepped atmosphere calcination with varied duration. The property of oxygen vacancies is verified by XRD, TEM, XPS and EPR analysis. With this facile treatment, the solar water splitting performance has been investigated. The enhanced photocurrent is about 1.96 mA cm−2 at 1.23 VRHE for the photoanode after 1.5 h calcination, which can keep constant even after 10 h illumination. Further study reveals that the maximum IPCE value of the photoanode reaches 56.5%. The creation of oxygen vacancies can lower the corresponding band gap for about 0.1 eV, which enhances the light absorption performance at the wavelength range from 750 to 620 nm. This photoanode displays the shortest charge transfer duration about 0.919 ms and the highest DC photocurrent about 597.13 × 10–8 mA cm−2 based on IMPS measurement. The electronic property and interfacial resistance of the photoanode are also characterized by Mott–Schottky and EIS measurement. The corresponding detailed mechanism is discussed in this paper.Graphical abstract[graphic not available: see fulltext]Schematic diagram and summary of the mechanism of oxygen vacancies introduced to the surface of α-Fe2O3 photoanode during solar water splitting.

Gao, Qiang; Jia, Liang; Zhang, Aiqin; Wang, Li; Peng, Hao; Wang, Wenkai; Zhou, Shenglin; Xiang, Jun; Chen, Yi; Fan, Haojun

doi: 10.1007/s10853-022-07893-3pmid: N/A

A type of porous polyurea microspheres for matting coating were prepared by precipitation polymerization in H2O/Acetonitrile (AN) solution, using isophorone diisocyanate (IPDI) as polymerized monomer, 2, 4-diaminobenzenesulfonic acid sodium salt as hydrophilic monomer and polyvinylpyrrolidone (PVP) as porogen. The effect of the type of porogen, reaction temperature, dry methods, post-perforation method and polyvinylpyrrolidone loading on the surface porosity was investigated. Meanwhile, the effect of the surface porosity and roughness of microspheres on the matting properties of the coating was also investigated. The results indicated that PVP porogen has played an important role in regulating the surface porosity of microspheres and shows superior perforation. When 15 wt% PVP (based on isophorone diisocyanate loading) was used as porogen, the reaction was carried at 50 °C in a shorter time, and the crude product was dried in a state of water dispersion at 100 °C, the resultant microspheres with maximal porous surface can be achieved. Post-perforation can further increase the surface roughness and porosity of polyurea microspheres without changing its particle size. When 5 wt% porous polyurea microspheres were added to the water-based polyurethane (WPU) coating, the gloss of the coating decreased from 6.27° to 1.14° (60° incident angle).Graphical Abstract[graphic not available: see fulltext]

Qian, Yanfeng; Wan, Xianglong; Cui, Hao; Mo, Lu; Jia, Jingxuan; Chen, Zhibo; Gao, Meiling; Li, Wenyang; Ding, Guoxin; Cheng, Guojun

doi: 10.1007/s10853-022-07827-zpmid: N/A

The cost, flux and rejection rate of the membrane are the main factors in the process of water reclamation and reuse. A new type of composite membrane can be prepared by using fly ash (FA) and polyurethane (PU). The structure and properties of composite membrane can be adjusted by the theory of pigment volume concentration (PVC) to treat wastewater containing methylene blue (MB). The morphology, FT-IR spectroscopy, wettability, diffusivity, flux and rejection rate of the composite membrane were studied. The results showed that when PVC was close to the critical pigment volume concentration (CPVC), the performances of the 3# (PVC = 40.03%) composite membrane, the mass ratio of FA to PU was 1.44: 1, were the best. The flux and rejection rate for MB solution of the 3# membrane were 66.52 L·m−2·h−1 and 96.77%, respectively. At the same time, there was no serious pollution on the membrane with a long-term application. In addition, several typical organic wastewaters were treated by this composite membrane. The rejection rates for organic pollutants such as Rhodamine B, phenol and actual industrial wastewater were 96.12%, 96.48%, and 97.58%, respectively. The sustainable technology for the recovery and reuse of water by using solid waste in wastewater treatment has good environmental and social benefits.

Yang, Ruilu; Zhang, Qi; Li, Chunjian; Zhang, Jian; Xin, Yangyang; Ju, Xiaoqian; Wang, Dechao; Shi, Jian; Zheng, Yaping

doi: 10.1007/s10853-022-07839-9pmid: N/A

The copper ion adsorption in wastewater treatment has gained increasing attention, which lies in the development of efficient adsorption materials. Herein, we demonstrated a novel class of macroscopic liquid-like three-dimensional (3D) graphene oxide (GO)-based derivatives for copper ion adsorption. To be specific, a supermolecular self-assembly process of GO in water induced by melamine and phytic acid, thus generating three-dimensional porous structural GO backbone. Then, the polyetheramine (M2070) and organosilane (KH560) were tethered via the covalent linkage, thus forming flexible oligomer species with silicon hydroxyl groups. Then, the oligomer species were attached to the surface of the GO backbone, yielding a novel class of black, homogenous GO-based derivatives. As expected, the liquid-like GO-based derivative presents the superior copper ion removal ability due to the synergistic effect of additions (melamine, phytic acid) and 3D porous structural backbone. More significantly, we presume that the rich libraries of organic oligomer species, together with other 2D nanosheets-based backbones (e.g., MXene, boron nitride, hydrotalcite, etc.), undoubtedly provide more convenience for the further construction of liquid-like 3D derivatives, eventually open a new era of advancing the development of novel adsorbents for heavy ions remove.

Wang, Ying; Yang, Ling Xu; Liu, Rui Jia; Liu, Hui Jun; Chi, Xiang; Zeng, Chao Liu; Fu, Chao

doi: 10.1007/s10853-022-07858-6pmid: N/A

Here, we report for the first time, a novel CrB/Cu(Al) composite is successfully fabricated by hot-pressed sintering of Cu and MAB phase Cr2AlB2 powders, which was prepared by a two-step molten salt method. The microstructure, mechanical properties and electrical conductivity of the composites were also investigated. Results show that homogeneous and compact composites composed of CrB and Cu (Al) solid solution are obtained, and the grain size of Cu matrix dramatically decreases from 56.41 to ~ 3 μm when Cr2AlB2 was added into Cu matrix. In addition, an alternate structure and good interfacial bonding between ceramic and Cu matrix are observed, which are beneficial for ceramic particles to bear loads and result in high mechanical strength. The Vickers hardness of Cu–20Cr2AlB2 composite is around 140 HV1.0 with electrical conductivity of 20.69% IACS. The tensile and yield strength of the composite are as high as 393.56–289.65 MPa, respectively.Graphical Abstract[graphic not available: see fulltext]

Koide, Noriatsu; Marumo, Tomoki; Arai, Yutaro; Hasegawa, Makoto; Nishimura, Toshiyuki; Inoue, Ryo

doi: 10.1007/s10853-022-07861-xpmid: N/A

The heat resistance of carbon fiber-reinforced ultra-high-temperature ceramic matrix composites (C/UHTCMCs) was characterized by arc-wind tunnel testing with heat fluxes of 2, 4.54, and 6.68 MW/m2. C/UHTCMCs were fabricated via Zr-Ti binary alloy (Zr-20at%Ti, Zr-64at%Ti, Zr-80at%Ti) melt infiltration. The thickness and weight changes of the specimen were dependent on the composition of the infiltrated Zr-Ti alloy. Microstructural and thermodynamic analyses revealed that formed oxides on the surface of composites are composed of ZrO2 solid solution, ZrTiO4 solid solution, and TiO2 solid solution. The composition of oxides also depends on the composition of infiltrated alloys. The difference originates from the formation and composition of oxide scales and the dynamic pressure. Especially, formation of liquid oxides accelerates the recession of composites because liquid oxides are disappeared from the surface owing to the dynamic pressure during arc-wind tunnel testing. To withstand aerodynamic heating above 2000 °C, formation of a solid (and liquid) oxide on the exposed surface is required to reduce recession.

Zhu, Jishi; Li, Xinshuo; Yang, Rui; Wen, Jin; Li, Xiaoke

doi: 10.1007/s10853-022-07863-9pmid: N/A

The widespread application of solar-thermal absorbers is currently hindered by their low absorption efficiency and high capital cost. Therefore, many initiatives, including direct absorption solar collectors (DASCs), are currently under way to improve the efficiency of the absorbers. In this regard, the application of TiN-modified h-BN nanosheets in DASCs is studied in this paper. Their superior solar absorptivity and thermal conductivity are based on the plasma plasmon effect of nanoparticles and the high thermal conductivity of h-BN nanosheets, respectively. In the experiment, five different concentrations (20, 40, 60, 80, 100 ppm) of TiN@h-BN composite nanofluids were prepared by a two-step method. The stability and optical properties of the nanofluids were analyzed. In addition, thermal loss and exergic efficiency of photothermal conversion system were analyzed and discussed. Combined with localized surface plasmon resonance (LSPR) of TiN nanoparticles and h-BN light reflection properties, the photothermal conversion of TiN@h-BN composite nanofluids was improved in DASCs. The 80 ppm nanofluid showed the best exergic efficiency, with an average exergic efficiency of 83%. Meanwhile, the photothermal conversion efficiency of 80 ppm TiN@h-BN composite nanofluid reaches the maximum 78%. This work provides new strategies for harnessing the full spectrum of solar energy and controlling the photothermal properties of nanofluids.Graphical Abstract[graphic not available: see fulltext] Schematic diagram of photothermal conversion system of TiN@h-BN nanofluids.