Titanium Phosphate Nanoplates Modified With AgBr@Ag Nanoparticles: A Novel Heterostructured Photocatalyst With Significantly Enhanced Visible Light Responsive Activity

Efficient degradation of tetracycline antibiotics using a novel rGO/Ag/g-C3N4 photocatalyst for hospital wastewater treatment

This study focuses on the development of an efficient photocatalyst for degrading hospital wastewater, specifically targeting the degradation of the antibiotic tetracycline (TC). We introduce a novel 2D/2D heterostructure photocatalyst composed of graphitic carbon nitride (g-CN), functionalized with silver nanoparticles (Ag NPs) and reduced graphene oxide (rGO). The primary aim is to enhance the photocatalytic performance of g-CN through the synergistic effects of Ag NPs and rGO. The rGO/Ag/g-CN nanocomposites demonstrated remarkable photocatalytic activity, achieving over 97% TC degradation within 60 min under commercial LED light irradiation. Additionally, these photocatalysts were used to remove other antibiotics, such as doxycycline hydrochloride and ofloxacin, and it was observed that the nanocomposite effectively removed these antibiotics as well. This enhanced performance is attributed to the surface plasmon resonance (SPR) effects of Ag NPs and the electron sink properties of rGO, which were confirmed through comprehensive physicochemical characterization. Various concentrations of Ag NPs and rGO were tested to optimize the nanocomposite synthesis, with optical and electrical characterizations, including photoluminescence (PL), electrochemical impedance spectroscopy (EIS), and Mott-Schottky (M-S) measurements, revealing higher electron-hole pair generation rates and carrier concentrations in the rGO/Ag/g-CN nanocomposites compared to pristine g-CN, Ag/g-CN, and rGO/g-CN. The results demonstrate the potential of the rGO/Ag/g-CN photocatalyst as a cost-effective and scalable solution for the treatment of medical pollutants in wastewater.

A Mini Review on Borate Photocatalysts for Water Decomposition: Synthesis, Structure, and Further Challenges

The development of novel photocatalysts, both visible and UV-responsive, for water decomposition reactions is of great importance. Here we focused on the application of the borates as photocatalysts in water decomposition reactions, including water splitting reaction, hydrogen evolution half-reaction, and oxygen evolution half-reaction. In addition, the rates of photocatalytic hydrogen evolution and oxygen evolution by these borate photocatalysts in different water decomposition reactions were summarized. Further, the review summarized the synthetic chemistry and structural features of existing borate photocatalysts for water decomposition reactions. Synthetic chemistry mainly includes high-temperature solid-state method, sol-gel method, precipitation method, hydrothermal method, boric acid flux method, and high-pressure method. Next, we summarized the crystal structures of the borate photocatalysts, with a particular focus on the form of the B-O unit and metal-oxygen polyhedral in the borates, and used this to classify borate photocatalysts, which are rarely mentioned in the current photocatalysis literature. Finally, we analyzed the relationship between the structural features of the borate photocatalysts and photocatalytic performance to discuss the further challenges faced by the borate photocatalysts for water decomposition reactions.

Constructing NiS2/NiSe2 heteroboxes with phase boundaries for Sodium-Ion batteries

Reasonable design and synthesis of anode materials with high capacity, excellent rate capability and good cycling stability is vital for the pragmatic application of sodium-ion batteries (SIBs). Transition metal chalcogenides possess immense potential on account of their distinguished redox reversibility and high theoretical specific capacity. Herein, the hollow metal sulfide/metal selenide (NiS₂/NiSe₂) heteroboxes with rich phase boundaries have been manufactured as anode for SIBs. The lattice distortion and charge redistribution at the phase boundary of the as-prepared NiS₂/NiSe₂ heteroboxes can expose more active sites, which is profitable to the adsorption of Na⁺ and accelerate the sodium storage kinetics process, and the unique hollow porous structure is conducive to buffering the volume expansion and can facilitate the penetration of electrolyte during the repeated Na⁺ de-intercalation process. By virtue of these advantages, the NiS₂/NiSe₂ heteroboxes delivers a good rate capability, where the average capacity at 10 A g^-1 in comparison with 0.1 A g^-1 is 64.3%. Otherwise, it exhibits an ultralong reversible capacity of 292 mA h g^-1 after 2000 cycles at 10 A g^-1 with only 0.0125% average capacity decay per cycle. The rational construction of phase boundary with unique structure in this article has guiding significance for the manufacture of progressive SIBs anode materials.

Enhancing electrochemical performance of electrode material via combining defect and heterojunction engineering for supercapacitors

The poor conductivity and deficient active sites of transition metal oxides lead to low energy density of supercapacitors, which limits their wide application. In this work, double transition metal oxide heterojunctions with oxygen vacancy (V_o-ZnO/CoO) nanowires are prepared by effective hydrothermal and thermal treatments. The formation of the heterojunction results in the redistribution of interface charge between ZnO and CoO, generating an internal electric field to accelerate the electron transport. Meanwhile, oxygen vacancies can enhance the redox reaction activity to further improve the electrochemical kinetics of the electrode material. Therefore, the prepared V_o-ZnO/CoO can provide a superior specific capacity of 845 C g^-1 (1 A g^-1). An asymmetric supercapacitor with the V_o-ZnO/CoO as positive electrode shows a higher energy density of 51.6 Wh kg^-1 when the power density reaches 799.9 W kg^-1. This work proposes a synergistic combination of defect and heterojunction engineering to improve the electrochemical properties of materials, providing an important guidance for material design in energy-storage field.

Shape tailoring of AgBr microstructures: effect of the cations of different bromide sources and applied surfactants

Investigations regarding AgBr-based photocatalysts came to the center of attention due to their high photosensitivity. The present research focuses on the systematic investigation regarding the effect of different alkali metal cation radii and surfactants/capping agents applied during the synthesis of silver-halides. Their morpho-structural and optical properties were determined via X-ray diffractometry, diffuse reflectance spectroscopy, scanning electron microscopy, infrared spectroscopy, and contact angle measurements. The semiconductors' photocatalytic activities were investigated using methyl orange as the model contaminant under visible light irradiation. The correlation between the photocatalytic activity and the obtained optical and morpho-structural properties was analyzed using generalized linear models. Moreover, since the (photo)stability of Ag-based photoactive materials is a crucial issue, the stability of catalysts was also investigated after the degradation process. It was concluded that (i) the photoactivity of the samples could be fine-tuned using different precursors and surfactants, (ii) the as-obtained AgBr microcrystals were transformed into other Ag-containing composites during/after the degradation, and (iii) elemental bromide did not form during the degradation process. Thus, the proposed mechanisms in the literature (for the degradation of MO using AgBr) must be reconsidered.

Systematic investigation of the effect of different alkali metal cation radii and shape-tailoring agents applied during the synthesis of AgBr-based photocatalysts.