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Among the traditional treatment processes for purifying wastewater contaminated with Rhodamine B (RhB), semiconductor photocatalysis is the most effective technology because it can oxidize organic pollutants and convert them into CO2, H2O, and other harmless molecules in a safe and efficient manner. According to literature research, it is feasible to enhance the performance of g‐C3 N4 as a photocatalyst by constructing a heterojunction with other photocatalytic materials. Morphological regulation of carbon nitride (g‐C3N4) is a viable strategy for improving its photocatalytic activities. By controlling the morphology of g‐C3N4, factors such as light absorption, specific surface area, charge separation, and reaction sites can be optimized to enhance its photocatalytic efficiency. Three‐dimensional tremella‐like carbon nitride (3DT‐CN) and 3D‐CN/TiO2/HNTs (halloysite nanotubes) were prepared using bubble templates and an impregnation method respectively. The Z‐scheme heterojunction structure constructed by 3D‐CN and TiO2 promotes electron‐hole separation. Catalytic experiments demonstrated that under irradiation for 120 min, the 3D‐CN/TiO2/HNTs catalyst could eliminate 86.48 % of Rhodamine B (RhB). Additionally, active radicals such as e‐, h+, ⋅OH, and ⋅O2‐ are involved in RhB degradation. Therefore, the three‐dimensional tremella‐like 3D‐CN/TiO2/HNTs heterojunction photocatalyst has great potential for environmental purification. [ABSTRACT FROM AUTHOR]

The novel BaSnO3/TiO2@HNTs photocatalysts were successfully synthesized by co‐precipitation peroxide and sol‐gel methods. Microstructures, morphologies, compositions, optical and electrochemical properties of the composites were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), fourier‐transform infrared spectroscopy (FT‐IR), UV‐vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), Brunauer‐Emmett‐Teller (BET), electrochemical impedance spectroscopy (EIS) and ion chromatography (IC) methods. The effects of different mass ratios of BaSnO3 and TiO2@HNTs, initial concentration and pH of methylene blue (MB) on the photocatalytic degradation performance of the composites were studied via photodegradation of MB under simulated sunlight irradiation. The characterization results showed that BaSnO3/TiO2 heterojunction and halloysite nanotubes (HNTs) enhanced the electron‐hole pairs separation. The BaSnO3/TiO2@HNTs (BTH‐0.6) composites presented the highest specific surface area (67.957 m2/g), photocatalytic activity (92 %), and MB (Ct=40 mg/L, pH 7) degradation efficiency (2‐4 times that of TiO2, BaSnO3 and BaSnO3/TiO2). Furthermore, the capture experiments verified that ⋅OH, h+ and ⋅O2− were the main active substances during the photo‐catalytic reaction, and a possible degradation mechanism was suggested for their photocatalytic degradation in the presence of BaSnO3/TiO2@HNTs. [ABSTRACT FROM AUTHOR]

In this study, to enhance the peroxymonosulfate (PMS)-assisted photocatalytic degradation of Rhodamine B (RhB) under visible light over TiO 2 , a novel halloysite nanotube (HNTs) supported TiO 2 composite photocatalyst was prepared by the sol-gel method. The crystal structure and bonding information of samples were investigated by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–visible diffuse reflection spectroscopy (DRS), photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) were used to characterize the morphology, optical properties and energy band structure of the samples. The composite with weight ratio of 1:5 (HNTs/TiO 2) (named HT-20) exhibited apparently enhanced PMS-assisted photocatalytic RhB degradation efficiency and can degrade approximately 95.31 % of RhB in 30 min, and the first-order rate constants (k) of HT-20-PMS system is about 54.5 times higher than that of B–TiO 2. In addition, the possible mechanism of enhanced PMS-assisted photocatalytic activity of HT-20 was proposed. The improvement of photocatalytic activity in the composite photocatalyst can be ascribed to the large surface area and strong adsorption capacity of HNTs. • TiO 2 /HNTs have been synthesized via a sol-gel method at low-temperature. • Synergistic interaction of B–TiO 2 /HNTs catalyst and Peroxymonosulfate enhances the photocatalytic efficiency of RhB. • Determined the energy band structure of the composite material and the reaction mechanism of the contaminants. • Addition of inhibitors significantly reduced the grain size of B–TiO 2. [ABSTRACT FROM AUTHOR]

The novel Bi/BaSnO 3 @halloysite nanotubes (Bi/BaSnO 3 @HNTs) photocatalyst was successfully synthesized by precipitation-photoreduction method. Crystal structure, morphology, composition, optical property and band structure of photocatalysts were investigated by X-ray diffraction and transmission electron microscopy, scanning electron microscopy and Brunauer-Emmett-Teller technique, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy and photoluminescence spectroscopy, and Mott-Schottky method, respectively. The catalytic activity of photocatalysts was evaluated by the removal efficiency of methylene blue solution under visible light irradiation. Among all samples, the Bi/BaSnO 3 @HNTs catalyst presented the lowest carrier recombination and the best photocatalytic activity (90.2%). Meanwhile, a possible mechanism for the enhanced catalytic activity of Bi/BaSnO 3 @HNTs was proposed. The improved photocatalytic performance can be attributed to the surface plasmon resonance effect and the local electromagnetic field of metallic Bi, and the large specific surface area and strong adsorption capacity endowed by HNTs. [Display omitted] • Bi/BaSnO 3 @HNTs composite was synthesized by precipitation-photoreduction method. • The SPR effect and local electromagnetic field of Bi increase carriers' separation. • The introduction of HNTs significantly reduces the particle size of photocatalyst. • Bi/BaSnO 3 @HNTs photocatalyst exhibits excellent photocatalytic activity under visible light. [ABSTRACT FROM AUTHOR]