Preparation, Characterization, and Photocatalytic Performance of NdPW12O40/TiO2 Composite Catalyst

Visible light-driven novel Bi2Ti2O7/CaTiO3 composite photocatalyst with enhanced photocatalytic activity towards NO removal

Photocatalysis is regarded as a promising technology for removal of nitrogen oxide (NO), however, the low photocatalytic efficiencies under visible light irradiation and the deactivation of the photocatalyst are as yet the significant issues that should be addressed. In this work, visible-light-driven Bi₂Ti₂O₇/CaTiO₃ heterojunction composites were synthesized by a facile in-situ hydrothermal method. The Bi₂Ti₂O₇/CaTiO₃ composites displayed superior visible light photocatalytic activity than pure CaTiO₃ and pure Bi₂Ti₂O₇ in the removal of NO at the 600 ppb level in air. Among all the composites, Bi₂Ti₂O₇/CaTiO₃ containing 20 wt% Bi₂Ti₂O₇ exhibited the best photocatalytic activity, achieving a maximum removal efficiency of 59%. The improved photocatalytic performance is mainly attributed to the strong visible-light-absorbing ability, the presence of an appropriate density of oxygen vacancy defects and the formation of heterojunction between CaTiO₃ and Bi₂Ti₂O₇, resulting in an efficient charge separation at the interface as proven by photoluminescence (PL) and photo-induced current measurements. According to trapping experiments and spin-trapping ESR analysis, the ^•O₂^- and h⁺ are the principal reactive species involved in the photocatalytic NO removal. In addition, the as-obtained Bi₂Ti₂O₇/CaTiO₃ composite showed good chemical stability, which is beneficial for practical applications in air pollution removal.

3-Bromopyridine-Heterogenized Phosphotungstic Acid for Efficient Trimerization of Biomass-Derived 5-Hydroxymethylfurfural with 2-Methylfuran to C21 Fuel Precursor

The production of long-chain carbon compounds (C9-C21) from biomass derivatives to alternate traditional fossil diesel is sustainable, eco-friendly, and potentially economic for modern industry. In this work, phosphotungstic acid heterogenized by 3-bromopyridine was achieved using a solvothermal method, which was demonstrated to be efficient for trimerization of biomass-derived 5-hydroxymethylfurfural (HMF) with 2-methylfuran (2-MF) to C21 fuel precursor (57.1% yield) under mild reaction conditions. The heterogeneous acidic catalyst could be reused for four consecutive cycles without obvious loss of activity, and different characterization techniques (e.g., XRD (X-ray diffraction), TG (thermogravimetric analysis), SEM (scanning electron microscope), FT-IR (Fourier transform infrared spectroscopy), and BET (Brunauer-Emmet-Teller)) were utilized to investigate the performance of the catalyst. In addition, a plausible reaction pathway was postulated, on the basis of results obtained by NMR (nuclear magnetic resonance) and GC-MS (gas chromatography-mass spectrometer). This strategy provides a facile and efficient approach to prepare a recyclable acidic catalyst for the production of diesel fuel precursor from biomass via controllable polymerization.

The effects of surfactant in the sol–gel synthesis of CuO/TiO2 nanocomposites on its photocatalytic activities under UV-visible and visible light illuminations

Effective and low-cost CuO/TiO₂ nanocomposites were prepared at room temperature by a surfactant-assisted sol–gel method for photocatalytic activities under UV-visible and visible light irradiations.

PtNixCoy concave nanocubes: synthesis and application in photocatalytic hydrogen generation

PtNi_xCo_y alloy concave nanocubes coupled with CdS nanorods were applied in the H₂ evolution reaction under visible light irradiation.

Ultrathin Ni(OH)2 nanosheets: a new strategy for cocatalyst design on CdS surfaces for photocatalytic hydrogen generation

Ultrathin metal materials exhibit quantum size and surface effects that give rise to unique catalytic properties. In this paper, we report a facile liquid synthesis method for polyvinylpyrrolidone (PVP, K30) capped ultrathin Ni(OH)₂ nanosheets with lamellar structure. The as-prepared ultrathin Ni(OH)₂ nanosheets coupled with CdS nanorods exhibit excellent activity in hydrogen generation from water splitting under visible light. The H₂ evolution rate of Ni(OH)₂/CdS, 40.18 mmol h⁻¹ g_Cat.⁻¹ with a quantum efficiency of 66.1% at 420 nm, is ca. 1.5 times that of Pt/CdS with an optimal loading amount (1.25 wt%) under the same reaction conditions. Considering the cost of photocatalysts, the ultrathin Ni(OH)₂ nanosheet coupled CdS photocatalyst may have a promising commercial application in photocatalytic hydrogen production.

In this report, ultrathin Ni(OH)₂ nanosheets coated CdS photocatalyst for photocatalytic hydrogen generation under visible light has been explored.

Pt–Nixalloy nanoparticles: a new strategy for cocatalyst design on a CdS surface for photo-catalytic hydrogen generation

Solar photocatalytic water splitting for the production of hydrogen has been a core aspect for decades. A highly active and durable photocatalyst is crucial for the success of the renewable hydrogen economy. To date, the development of highly effective photocatalysts has been seen by the contemporary research community as a grand challenge. Thus, herein we put forward a sincere attempt to use a Pt–Ni_x alloy nanoparticle (NP) cocatalyst loaded CdS photocatalyst ((Pt–Ni_x)/CdS) for photocatalytic hydrogen production under visible light. The Pt–Ni_x alloy NP cocatalyst was synthesized using a one-pot solvothermal method. The cocatalyst nanoparticles were deposited onto the surface of CdS, forming a Pt–Ni_x/CdS photocatalyst. Photocatalytic hydrogen production was carried out using a 300 W Xe light equipped with a 420 nm cut-off filter. The H₂ evolution rate of the Pt–Ni₃/CdS photocatalyst can reach a value as high as 48.96 mmol h⁻¹ g⁻¹ catalyst, with a quantum efficiency of 44.0% at 420 nm. The experimental results indicate that this Pt–Ni₃/CdS photocatalyst is a prospective candidate for solar hydrogen generation from water-splitting.

In this report, PtNi_x alloy NPs coupled with a CdS photocatalyst for photocatalytic hydrogen generation under visible light have been explored.

Facile fabrication of heterostructured cubic-CuFe2O4/ZnO nanofibers (c-CFZs) with enhanced visible-light photocatalytic activity and magnetic separation

Photocatalytic mechanism of a c-CuFe₂O₄/ZnO nanofibers (c-CFZs) p–n heterojunction.

Synergistic effect of N- and F-codoping on the structure and photocatalytic performance of TiO2

Three types of TiO2 nanostructures were synthesized via a facile hydrolysis method at 195°C. Effects of the preparation method and doping with N and F on the crystal structure and photocatalytic performance of TiO2 were investigated. The nanomaterials were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller porosimetry, ultraviolet-visible diffuse reflectance spectroscopy and fluorescent emission spectra. Their photo-catalytic activity was examined by the photodegradation of methylene blue in aqueous solution under both ultra-violet and visible light irradiation. The results show that nitrogen and fluorine co-doped anatase TiO2 had the characteristics of a smaller crystalline size, broader light absorption spectrum and lower charge recombination than pure TiO2. Most importantly, more efficient photocatalytic activity under both ultra-violet and visible light was observed. The obtained N-F-TiO2 nanomaterial shows considerable potential for water treatment under sunlight irradiation.

Facile synthesis of WO3 with reduced particle size on zeolite and enhanced photocatalytic activity

WO₃ supported on zeolite-Y (WO3-ZY) was successfully synthesized by a facile impregnation method and well characterized by various techniques.

Photocatalytic activity of novel AgBr/WO3 composite photocatalyst under visible light irradiation for methyl orange degradation

A novel AgBr/WO(3) composite photocatalyst was synthesized by loading AgBr on WO(3) substrate via deposition-precipitation method and characterized by XRD, SEM and DRS. The as-prepared AgBr/WO(3) was composed of monoclinic WO(3) substrate and face-centered cubic AgBr nanoparticles with crystalline sizes less than 56.8 nm. AgBr/WO(3) had absorption edge at about 470 nm in the visible light region. The optical AgBr content in AgBr/WO(3) was 0.30:1 (Ag/W) at the corresponding apparent rate, k(app), of 0.0160 min(-1) for MO degradation. The highest k(app) was 0.0216 min(-1) for 4 g/L catalyst. The OH acted as active species. Addition of H(2)O(2) within 0.020 mmol/L can efficiently trap electrons to generate more OH and further improved photocatalytic activity of AgBr/WO(3).

Preparation, characterization and activity evaluation of TiN/F-TiO2 photocatalyst

In this paper, F-TiO(2) and TiN/F-TiO(2) nanoparticle photocatalysts were prepared by ball milling. The photocatalysts were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), terephthalic acid photoluminescence probing technique (TA-PL), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflection spectroscopy (DRS). The photocatalytic activity of the photocatalysts was evaluated by photocatalytic degradation of methylene blue (MB) and rhodamine B (RhB). The results showed that the photocatalytic activity of the F-TiO(2) was much higher than that of TiO(2), and the photocatalytic activity of the TiN/F-TiO(2) was much higher than that of TiO(2) and F-TiO(2) under UV light irradiation. The optimum percentage of doped TiN is 0.2 wt.%. Compared with pure TiO(2), the photoabsorption wavelength range of the TiN/F-TiO(2) and F-TiO(2) photocatalysts red shifts and improves the utilization of the total spectrum. The effect of ball milling time on the photocatalytic activity of the photocatalysts was also investigated. The optimum ball milling time is 12 h. The mechanisms of influence on the photocatalytic activity of the photocatalysts were also discussed.

Photocatalytic performance of TiO2 catalysts modified by H3PW12O40, ZrO2 and CeO2

The binary composite photo-catalysts CeO2/TiO2, ZrO2/TiO2 and the ternary composite photo-catalysts H3PW12O40-CeO2/TiO2, H3PW12O40-ZrO2/TiO2 were prepared by sol-gel method. The catalysts were characterized by thermogravimetric-differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The photocatalytic elimination of methanol was used as model reaction to evaluate the photocatalytic activity of the composite catalysts under ultraviolet light irradiation. The effects of doped content, activation temperature, time, initial concentration of methanol and gas flow rate on the catalytic activity were investigated. The results showed that after doping a certain amount of CeO2 and ZrO2, crystallization process of TiO2 was restrained, particles of catalysts are smaller and more uniform. Doping ZrO2 not only significantly improved the catalytic activity, but also increased thermal stability. Doping H3PW12O40 also enhanced the catalytic activity. The catalytic activities of binary and ternary composite photocatalysts were significantly higher than un-doped TiO2. The dynamics law of photocatalytic reaction over the binary CeO2/TiO2 and ZrO2/TiO2 catalysts has been studied. The activation energy 15.627 and 15.631 kJ/mol and pre-exponential factors 0.5176 and 0.9899 s(-1) over each corresponding catalyst were obtained. This reaction accords to the first order dynamics law.