Controlled assembly of Sb₂S₃ nanoparticles on silica/polymer nanotubes: insights into the nature of hybrid interfaces

N, Ru Codoped Pellet Drum Bundle-Like Sb2S3: An Efficient Hydrogen Evolution Reaction and Hydrogen Oxidation Reaction Electrocatalyst in Alkaline Medium

Though investigations have been made on several metal chalcogenides in hydrogen evolution reactions (HERs) and hydrogen oxidation reactions (HORs), antimony sulfide (Sb₂S₃) has not generated much attention. In this direction, the present work reports on the synthesis of N, Ru codoped pellet drum bundle-like antimony sulfide (Sb₂S₃) via a simple reflux method. Subsequent HER and HOR electrocatalytic investigations in 1 M KOH revealed their suitability as an efficient and inexpensive alternative to platinum, as is evident from the overpotential (72 mV at a current density of 10 mA cm^-2), Tafel slope (193 mV/decade), exchange current density (1.42 mA/cm²), and breakdown potential at ∼0.6 V vs RHE, respectively. Such remarkable HER and HOR performance of N, Ru codoped Sb₂S₃ could be ascribed to the presence of relatively larger active sites compared to Sb₂S₃ and N-doped Sb₂S₃ individually due to synergistic effects arising from N and Ru dopants. Further, N, Ru codoped Sb₂S₃ demonstrated high intrinsic catalytic activity as indicated by its turnover frequency (2.03 s^-1) and current loss, corresponding to 35% after 10 h of continuous amperometric i-t operation. Alternatively, such excellent catalytic performance of N, Ru codoped Sb₂S₃ arises due to geometric lattice defects with surface oxygen vacancy, and the availability of abundant edges and its pellet drum-like morphology also cannot be overruled.

Amorphous Sb2S3 Nanospheres In-Situ Grown on Carbon Nanotubes: Anodes for NIBs and KIBs

Antimony sulfide (Sb2S3) with a high theoretical capacity is considered as a promising candidate for Na-ion batteries (NIBs) and K-ion batteries (KIBs). However, its poor electrochemical activity and structural stability are the main issues to be solved. Herein, amorphous Sb2S3 nanospheres/carbon nanotube (Sb2S3/CNT) nanocomposites are successfully synthesized via one step self-assembly method. In-situ growth of amorphous Sb2S3 nanospheres on the CNTs is confirmed by X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. The amorphous Sb2S3/CNT nanocomposites as an anode for NIBs exhibit excellent electrochemical performance, delivering a high charge capacity of 870 mA h g-1 at 100 mA g-1, with an initial coulomb efficiency of 77.8%. Even at 3000 mA g-1, a charge capacity of 474 mA h g-1 can be achieved. As an anode for KIBs, the amorphous Sb2S3/CNT nanocomposites also demonstrate a high charge capacity of 451 mA h g-1 at 25 mA g-1. The remarkable performance of the amorphous Sb2S3/CNT nanocomposites is attributed to the synergic effects of the amorphous Sb2S3 nanospheres and 3D porous conductive network constructed by the CNTs.

TiO2 decorated functionalized halloysite nanotubes (TiO2@HNTs) and photocatalytic PVC membranes synthesis, characterization and its application in water treatment

In this study photocatalyst, TiO₂@HNTs were prepared by  synthesizing TiO₂ nanoparticles in situ on the  functionalized halloysite nanotubes (HNTs) surface. Photocatalytic PVC membrane TiO₂@HNTs M2 (2 wt.%) and TiO₂@HNTs M3 (3 wt.%) were also prepared. Photocatalyst TiO₂@HNTs and photocatalytic PVC membranes were used to study the photocatalytic activity against the methylene blue (MB) and rhodamine B (RB) dyes in UV batch reactor. The structure and morphology of photocatalyst and photocatalytic PVC membrane were characterized by fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), UV-Vis spectrophotometer and photoluminescence (PL). The PL study showed that the oxygen vacancies and surface hydroxyl groups present on the surface of TiO₂@HNTs act as excellent traps for charge carrier, reducing the electron-hole recombination rate.TiO₂@HNTs 2 (2 wt.%) and TiO₂@HNTs 3 (3 wt.%) degraded MB dye up to 83.21%, 87.47% and RB dye up to 96.84% and 96.87%, respectively. TiO₂@HNT photocatalyst proved to be stable during the three consecutive cycle of photocatalytic degradation of the RB dye. TiO₂@HNTs M2 and TiO₂@HNTs M3 degraded MB dye up to 27.19%, 42.37% and RB dye up to 30.78%, 32.76%, respectively. Photocatalytic degradation of both the dyes followed the first-order kinetic model. Degradation product analysis was done using the liquid chromatography–mass spectrometry (LC-MS) and the results showed that the dye degradation was initiated by demethylation of the molecule. MB and RB dye degradation reaction were tested by TBA and IPA as OH^* and H⁺ scavengers respectively. Mechanism of photocatalytic activity of TiO₂@HNTs and photocatalytic PVC membrane were also explained.

Near-infrared-driven Cr(vi) reduction in aqueous solution based on a MoS2/Sb2S3 photocatalyst

A novel MoS₂/Sb₂S₃ composite with enhanced near-infrared photocatalytic efficiency was fabricated.

Sb2Se3 assembling Sb2O3@ attapulgite as an emerging composites for catalytic hydrogenation of p-nitrophenol

The construction and application of a new type of composite material are achieved more and more attention. However, expected Sb2Se3/attapulgite composites aim to use the low price, and high adsorption of attapulgite in assembling Sb2Se3 is quite difficult to be acquired by a facile and benign environmental hydrothermal method. In this manuscript, we developed a new way for preparation of an emerging composite by means of Sb2O3 as a media linking Sb2Se3 and attapulgite together, and finally won an emerging composite Sb2Se3/Sb2O3@attapulgite, which presented an excellent catalytic properties for catalytic hydrogenation of p-nitrophenol. It was noted that the Sb2Se3/Sb2O3@attapulgite composites exhibited a high conversion rate for the hydrogenation of p-nitrophenol that was up to 90.7% within 15 min, which was far more than the 61.5% of Sb2Se3 sample. The excellent catalytic performance was attributed to the highly dispersion Sb2Se3 microbelts and Sb2Se3@Sb2O3@attapulgite rods, which would improve the adsorption of the reactant species and facility electronic transfer process of the catalytic hydrogenation of p-nitrophenol.

Flux improvement, rejection, surface energy and antibacterial properties of synthesized TiO2-Mo.HNTs/PVC nanocomposite ultrafiltration membranes

The present work demonstrates the preparation of modified halloysite loaded with titanium dioxide (TiO₂) nanoparticles and its use as a nanofiller in a poly(vinyl chloride) (PVC) hybrid ultrafiltration (UF) membrane for advanced water treatment.

Perovskite LaFeO3/montmorillonite nanocomposites: synthesis, interface characteristics and enhanced photocatalytic activity

Perovskite LaFeO₃/montmorillonite nanocomposites (LaFeO₃/MMT) have been successfully prepared via assembling LaFeO₃ nanoparticles on the surface of montmorillonite with citric acid assisted sol-gel method. The results indicated that the uniform LaFeO₃ nanoparticles were densely deposited onto the surface of montmorillonite, mainly ranging in diameter from 10 nm to 15 nm. The photocatalytic activity of LaFeO₃/MMT was evaluated by the degradation of Rhodamine B (RhB) under visible light irradiation, indicating that LaFeO₃/MMT exhibited remarkable adsorption efficiency and excellent photocatalytic activity with the overall removal rate of RhB up to 99.34% after visible light irradiation lasting for 90 min. The interface characteristic and possible degradation mechanism were explored. The interface characterization of LaFeO₃/MMT suggested that LaFeO₃ nanoparticles could be immobilized on the surface of montmorillonite with the Si-O-Fe bonds. The abundant hydroxyl groups of montmorillonite, semiconductor photocatalysis of LaFeO₃ and Fenton-like reaction could enhance the photocatalytic degradation through a synergistic effect. Therefore, the LaFeO₃/MMT is a very promising photocatalyst in future industrial application to treat effectively wastewater of dyes.

Au encapsulated into Al-MCM-41 mesoporous material: in situ synthesis and electronic structure

A facile one-step technique is proposed for the successful synthesis of highly ordered Au/Al-MCM-41. The charge state of Au³⁺ in the mesoporous framework was partially reduced due to the accompanying Al when clay was used as source.

Controlled synthesis and visible light photocatalytic activity of Bi12GeO20 uniform microcrystals

We successfully synthesized uniform Bi₁₂GeO₂₀ microspheres and microtetrahedrons enclosed by four {111} facets using a controlled hydrothermal method for the first time. The photocatalytic activity of these regular-shaped products was further investigated by the degradation of RhB and gaseous formaldehyde under visible light irradiation (λ>420 nm). The Bi₁₂GeO₂₀ microtetrahedrons (s) exhibited enhanced photocatalytic activity and stability which is closely related to the high capacity of exposed {111} facets for uptake of O₂. The formation mechanism studies indicate that the Bi₁₂GeO₂₀ seeds were directed to grow into truncated microcubes, truncated microtetrahedrons, and then microtetrahedrons when the NaOH concentration was 5 M. The same batch of seeds only evolved into microspheres when the NaOH concentration was switched to 3 M. The difference in Bi₁₂GeO₂₀ morphology could be attributed to the rates of both crystal nucleation and crystal growth.

Novel one-pot fabrication of lab-on-a-bubble@Ag substrate without coupling-agent for surface enhanced Raman scattering

Through in-situ reduction of silver nitrate without using any coupling-agent, a substrate for surface-enhanced Raman scattering (SERS) was prepared by coating silver on hollow buoyant silica microspheres as a lab on a bubble (LoB). The silver coated LoBs (LoBs@Ag) floated on surface of a solution could provide a very convenient platform for the detection of target molecules in the solution. The LoBs@Ag substrate not only immobilized well-distributed Ag nanoparticles on the surface LoBs, but excluded the interference of coupling agents. This yielded high-resolution SERS spectra with excellent reproducibility. The adsorption of crystal violet (CV) on the LoBs@Ag substrate was investigated by means of SERS combined with density functional theory (DFT) calculations. The LoBs@Ag substrate exhibited a remarkable Raman enhancement effect for CV with an enhancement factor of 6.9 × 10(8) and wide adaptability from dye, pesticide to bio-molecules. On the basis of this substrate, a simple and sensitive SERS method was proposed for the determination of trace organic pollutants or bio-molecules.

Morphologic control of Sb-rich Sb2Se3 to adjust its catalytic hydrogenation properties for p-nitrophenol

Sb-rich Sb₂Se₃ with hollow sphere morphology is an efficient catalyst for the hydrogenation of p-nitrophenol.

Enhanced performance and interfacial investigation of mineral-based composite phase change materials for thermal energy storage

A novel mineral-based composite phase change materials (PCMs) was prepared via vacuum impregnation method assisted with microwave-acid treatment of the graphite (G) and bentonite (B) mixture. Graphite and microwave-acid treated bentonite mixture (GBm) had more loading capacity and higher crystallinity of stearic acid (SA) in the SA/GBm composite. The SA/GBm composite showed an enhanced thermal storage capacity, latent heats for melting and freezing (84.64 and 84.14 J/g) was higher than those of SA/B sample (48.43 and 47.13 J/g, respectively). Addition of graphite was beneficial to the enhancement in thermal conductivity of the SA/GBm composite, which could reach 0.77 W/m K, 31% higher than SA/B and 196% than pure SA. Furthermore, atomic-level interfaces between SA and support surfaces were depicted, and the mechanism of enhanced thermal storage properties was in detail investigated.

Palladium nanoparticles deposited on silanized halloysite nanotubes: synthesis, characterization and enhanced catalytic property

Palladium (Pd) nanoparticles were deposited on the surface of halloysite nanotubes (HNTs) modified with γ-aminopropyltriethoxysilane (APTES) to produce Pd/NH₂-HNTs nanocomposites. The results indicated that Pd nanoparticles were densely immobilized onto NH₂-HNTs with an average diameter of ~ 3 nm. The Pd distribution on the surface of silanized HNTs showed much more uniform, and the Pd nanoparticle size became smaller compared with those directly deposited onto HNTs without silanization. Systematic characterization demonstrated that APTES were chemically bonded onto HNTs, and further confirmed the bond formation between Pd and -NH₂ groups, which could ensure the firm deposit of Pd nanoparticles on the surface of silanized HNTs. The as-synthesized Pd/NH₂-HNTs exhibited an excellent catalytic activity in the liquid-phase hydrogenation of styrene to ethylbenzene with full conversion within 30 min. The mechanism of the deposit of Pd nanoparticles on silanized HNTs was also investigated.