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Semiconductor-based photocatalysis represents a promising technology for removing antibiotic given its cost effectiveness and environmental compatibility. However, finding suitable photocatalysts and semiconductors for practical applications can be challenging. This work aims to investigate the photocatalytic performance of as-synthesized photocatalysts under broad-spectrum from visible (Vis) to near-infrared (NIR) sunlight. In this work, a step-scheme (S-scheme) heterojunction photocatalyst, i.e., CuS/S–C3N4, was prepared, employing a single-step hydrothermal route. The synthesized photocatalyst showed excellent crystallinity and high purity content. The CuS loading provided a better NIR light response-ability and improved photocatalytic activity for CuS/S–C3N4. The 2 wt% CuS/S–C3N4 produced the highest tetracycline (TC) photodegradation rate, up to about 95% efficiency under Vis + NIR light irradiation. The result also showed that the 2 wt% CuS/S–C3N4 sample had a first-order kinetic constant (k) that was 6.2-fold higher than the pure S–C3N4 sample under Vis + NIR light irradiation. However, too much CuS content led to the presence of inactive sites on S–C3N4, which hampered the light absorption ability, thus leading to inadequate photocatalytic activity. In addition, the 2 wt% CuS/S–C3N4 sample also showed high photocatalytic stability and insignificant change of the composite structure before and after the experiments. In short, we can enhance the CuS/S–C3N4 photocatalytic activity by increasing the light response range and the separation efficiency of light-induced electrons and holes. Consequently, we have developed a novel strategy and experimental basis for S-scheme heterojunction to be fully utilized under broad-spectrum sunlight.

Semiconductor-metal heterostructure, especially represented by various inorganic semiconductors-platinum (Pt) hybrids, is widely applied in converting solar power to chemical energy. Given the scarcity of Pt and the availability of coupling, the development of a non-Pt regimen and facile assembly strategy is critical. In this study, CdxZn1-xS/Ti3C2 ultrathin MXene composites were availably prepared with a facile electrostatic assembly strategy. The unique 0D/2D assembly demonstrated remarkably enhanced performance toward photocatalytic hydrogen production compared with bare CdxZn1-xS. Spectroscopic characterization analysis and band theory discussion substantiated the effects of electronic interaction and the Schottky barrier arising from intimate contact of CdxZn1-xS and Ti3C2 MXene on the swift separation of photoinduced electron-hole pairs. Successful application of electrostatic self-assembled CdxZn1-xS with ultrathin MXene opens a new area of utilizing electrical difference and band theory to prepare rational semiconductor/MXene Schottky structure towards various photocatalytic reactions.

In this work, different carbon sources, such as nano-sized carbon black (CB), carbon nanotubes (CNT), carbon fibers (CF) and graphene (GR), were reacted with titanium micro-powders, to synthesise titanium carbide (TiC) in the mixed molten salts of LiCl–KCl–KF at 1100 °C for 6 h. There experiments were performed to investigate the accuracy of “carbon-template-growth” mechanism for the formation of TiC, that was proposed previously using micro-sized titanium and submicro-sized CB powders. The products synthesised from the different carbon sources were observed and characterised by scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The results showed that the visual morphologies of the TiC products mainly retained the shapes of the as-received carbon sources, that is, they presented an equiaxed-shape with a grain size of 10–20 nm from CB, a shell layer along the outer surface of the CNTs and CF, and a flake-shape with the GR. These morphologies reveal that the formation of TiC is indeed controlled by the “carbon-template-growth” mechanism.

β-Sialon powder containing nanofibers was synthesized at 1300–1450 °C for 5 h in nitrogen by using transition metals (Fe, Co and Ni) as catalysts. Such synthesis conditions obviously reduced the nitriding temperature (~100 °C) of β-Sialon and increased the degree of nitridation. Observations from the weight gain rates of specimens relative to the content of catalysts suggest that the nitridation process was accelerated sharply via the addition of 0–2.5 wt% metallic catalysts. In addition, the amount of nanofibers of β-Sialon found in the specimens increased with the amount of transition metals, which was governed by the VLS formation mechanism with the help of transition metals. It could be concluded that transition metals not only greatly accelerated the nitridation of Si but also facilitated the formation of β-Sialon nanofibers in the specimens, as the formed metal-containing liquid greatly enhanced the amount of vapor generation.

In order to verify the “Al2O3-template-formation” mechanism of magnesium aluminate (MA) spinel proposed previously using Al2O3 and MgO micro-powders as raw materials, in this work, MA spinel was synthesized by nanograined, plate-like, and fibrous Al2O3 in LiCl molten salt at 1150 °C for 3 h, respectively. The products were characterized by XRD, SEM, TEM, and EDS techniques, and the grain size of the products and raw materials were analyzed. The results showed clearly that the MA spinel was initially nucleated and subsequently developed to octahedral crystal. When the reaction further took place, when using nanograined Al2O3, the newly formed MA spinel seeds initially moved and attached to the surface of the large octahedral MA spinel crystal, and they were subsequently engulfed by the large MA spinel crystal, which further grew via layer-by-layer to become micro-sized crystal. Using plate-like or fibrous Al2O3 raw material, MgO diffused continuously into the interior of Al2O3 to form MA spinel with a gradient growth from surface to depth. These revealed that whatever shape of Al2O3 was used, the synthesis of MA spinel was governed by “Al2O3-template formation mechanism”, i.e., by the reaction of MgO diffusion into the Al2O3 templet in the molten salt.

Graphitic carbon nitride (g-C 3 N 4 ) prepared by traditional methods has various disadvantages, e.g., small specific surface area, low band gap, high photo-generated carriers recombination and low exfoliation efficiency, which limits its practical application. In this study, folded nano-porous graphene-like g-C 3 N 4 (abbreviated as FNPGLCN) was prepared by a simple but quite effective method of calcining urea in water. The effects of calcination temperature on crystal structure, energy band and microstructure of g-C 3 N 4 were investigated. The photocatalytic activity for methylene blue (MB) degradation under visible-light was evaluated. The results revealed that the FNPGLCN had higher specific surface area (197 m 2 /g) and larger band gap (2.87 eV) than bulk g-C 3 N 4 . With calcination temperature rising from 450 to 500 °C, the pore size and specific surface area of FNPGLCN increased. However, the pore structure almost disappeared and the thickness of g-C 3 N 4 became thinner at 550 °C. Compared with bulk g-C 3 N 4 , the photocatalytic degradation rate of FNPGLCN for MB increased from 0.131 to 1.298 h −1 . The significant enhancement of visible photocatalytic activity was mainly attributed to folded nano-porous structure, which simultaneously improved visible-light absorption range and strength, and enlarged the band gap and specific surface area of g-C 3 N 4 .

Aluminum oxynitride (AlON) ceramic was fabricated by in-situ hot pressing sintering (HPS) from Al 2 O 3 and AlN doped with Y 2 O 3 and La 2 O 3 as well as without dopant for comparison. Dense AlON ceramic with a relative density of 99.7% was obtained by HPS doped with 0.4 wt% Y 2 O 3 and 0.1 wt% La 2 O 3 at 1700 °C for 4 h. The maximum fracture toughness of AlON ceramic with and without dopant was 3.74 MPa m 1/2 and 2.27 MPa m 1/2 , respectively. The maximum Vickers hardness of AlON ceramic with and without dopant was 18.3 GPa and 16.5 GPa, respectively. Compared with those of undoped AlON ceramic, the relative density and the fracture toughness of Y 2 O 3 -La 2 O 3 co-doped AlON ceramic were obviously improved. Overlarge grain size would reduce the Vickers hardness of AlON. The sintering activation energy of Y 2 O 3 -La 2 O 3 co-doped AlON was about 57% of that of undoped AlON. The sintering activity of AlON was highly improved by co-doping with Y 2 O 3 and La 2 O 3 .

In this work, the effect of MgO addition on the sinterability and crystallization of sintered glass–ceramics prepared from powder mixtures of waste glass and fly ash was investigated. The bulk density of the glass–ceramics decreased with increasing the MgO content, reaching the maximum value at the sintering temperature of 1000 °C. The amounts of the glass-ceramic crystalline phases, i.e., pyroxene and forsterite, increased with the MgO content. Furthermore, when the MgO content increased from 5 to 25 wt%, the crystallization mechanism changed from bulk to surface crystallization. The flexural strength was significantly influenced by three factors, i.e., porosity, crystallinity, and crystal shape anisotropy, and reached the maximum value of 78 MPa for a 10 wt% content of MgO. Fast sintering promoted the densification process, thus increasing the glass-ceramic flexural strength. As a result, owing to their high strength and relatively low density, these sintered glass–ceramics appear promising for potential applications in lightweight construction tiles.

A macroporous silica film (MSF) was introduced as a buffer layer of material between a silicate glass (SG) layer and a polyurethane (PU) layer to form a new aeronautic laminated glass. Structure simulations of MSF were performed using the ANSYS software. Pore models, porosity factor models, and thickness models were established. X-direction stress, Y-direction stress, and equivalent stress of the models were determined. Simulation results indicate that the pore can effectively depress shear stress on the MSF–PU interface. Moreover, maximum X-direction stress, maximum compressive stress, and maximum equivalent stress on the MSF–PU interface all decrease rapidly and then increase slowly by increasing film thickness.

Ce1−xGdxO2−x/2 (GDC) powders with different Gd3+ contents (x = 0.05–0.3) were prepared by a simple citrate–nitrate combustion method. The influence of the Gd3+ doping content on the crystal structure and the electrical properties of GDC were examined. Many analysis techniques such as thermal analysis, X-ray diffraction, nitrogen adsorption analysis, scanning electron microscopy and AC impedance analysis were employed to characterize the GDC powders. The crystallization of the GDC solid solution occurred below 350 °C. The GDC powders calcined at 800 °C showed a typical cubic fluorite structure. The lattice parameter of GDC exhibited a linear relationship with the Gd3+ content. As compared with that sintered at other temperatures, the GDC pellet that sintered at 1300 °C had a high relative density of 97%, and showed finer microstructure. The conductivity of GDC was firstly increased and then decreased with the increase of the Gd3+ content. The sintered GDC sample with the Gd3+ content of 0.25 exhibited the highest conductivity of 1.27 × 10−2 S cm−1 at 600 °C.