scholarly journals Facile and Large-scale Synthesis of Defective Black TiO2−x(B) Nanosheets for Efficient Visible-light-driven Photocatalytic Hydrogen Evolution

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1048 ◽  
Author(s):  
JingCheng Xu ◽  
JiaJia Zhang ◽  
ZhengYang Cai ◽  
He Huang ◽  
TianHao Huang ◽  
...  

In the work, we firstly report the facile and large-scale synthesis of defective black TiO2−x(B) nanosheets via a dual-zone NaBH4 reduction method. The structure, physico-chemical, and optical properties of TiO2−x(B) nanosheets were systematically characterized by powder X-ray diffraction, Raman spectroscopy, UV-Vis absorption spectroscopy, and X-ray photoelectron spectroscopy, etc. The concentration of Ti3+ can be well tuned by NaBH4 reduction. With increasing the mass ratio of NaBH4 to TiO2(B), the generation of Ti3+ defects gives rise to the increased intensity of a broad band absorption in the visible wavelength range. It is demonstrated that the TiO2−x(B) photocatalyst synthesized with the mass ratio of NaBH4 to TiO2(B) of 3:1 exhibited an optimum photocatalytic activity and excellent photostability for hydrogen evolution under visible-light irradiation. By combining the advantages of 2D TiO2(B) nanosheets architecture with those of Ti3+ self-doping and simultaneous production of oxygen vacancy sites, the enhanced photocatalytic performance of the defective TiO2−x(B) nanosheets was achieved.

MRS Advances ◽  
2020 ◽  
Vol 5 (52-53) ◽  
pp. 2727-2735
Author(s):  
Nidhi ◽  
Tashi Nautiyal ◽  
Samaresh Das

AbstractSeveral techniques have been employed for large-scale synthesis of group 10 transition metal dichalcogenides (TMDCs) based on platinum and palladium for nano- and opto-electronic device applications. Nickel Sulphides (NixSy), belonging to group 10 TMDC family, have been widely explored in the field of energy storage devices such as batteries and supercapacitors, etc. and commonly synthesized through the solution process or hydrothermal methods. However, the high-quality thin film growth of NixSy for nanoelectronic applications remains a central challenge. Here, we report the chemical vapor deposition (CVD) growth of NiS2 thin film onto a two-inch SiO2/Si substrate, for the first time. Techniques such as X-ray photoelectron spectroscopy, X-ray Diffraction, Raman Spectroscopy, Scanning Electron Microscopy, have been used to analyse the quality of this CVD grown NiS2 thin film. A high-quality crystalline thin film of thickness up to a few nanometres (~28 nm) of NiS2 has been analysed here. We also fabricated a field-effect device based on NiS2 thin film using interdigitated electrodes by optical lithography. The electrical performance of the fabricated device is characterized at room temperature. On applying the drain voltage from -2 to +2 V, the device shows drain current in the range of 10-9 A before annealing and in the range of 10-6 A after annealing. This, being comparable to that from devices based on MoS2 and other two-dimensional materials, projects CVD grown NiS2 as a good alternative material for nanoelectronic devices.


2019 ◽  
Author(s):  
Siwei Yang ◽  
Yuanfang Shen ◽  
Yixin Hong ◽  
Ankang Hu ◽  
Xuewei Tu ◽  
...  

A novel photocatalyst 2-amino-5-fluorobenzotrifluoride@Fe-based metal–organic framework (2A5F@Fe–MOF) was designed and synthesized, which exhibits excellent photocatalytic performance to degrade water contaminant rhodamine B (RhB) under visible light with 99.2% degradation rate after 2h. The photocatalyst was characterized by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) as well as the analysis of morphological structure and chemical composition. Compared with pure Fe-MOF, the designed 2A5F@Fe-MOF photocatalyst appearance shows a transform from 2D to 3D, which maybe lead to the high photocatalytic activity toward RhB under visible light. The optimum conditions, such as ligand ratio, pH and concentration of RhB solution, were screened, also its degradation kinetic equations were built to give a typical reference for a large scale wastewater treatment.


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 355
Author(s):  
Ksenia O. Potapenko ◽  
Anna Yu. Kurenkova ◽  
Andrey V. Bukhtiyarov ◽  
Evgeny Yu. Gerasimov ◽  
Svetlana V. Cherepanova ◽  
...  

A series of solid solutions of cadmium and manganese sulfides, Cd1−xMnxS (x = 0–0.35), and composite photocatalysts, CdS-β-Mn3O4-MnOOH, were synthesized by precipitation with sodium sulfide from soluble cadmium and manganese salts with further hydrothermal treatment at 120 °C. The obtained photocatalysts were studied by the X-ray diffraction method (XRD), UV-vis diffuse reflectance spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and N2 low temperature adsorption. The photocatalysts were tested in hydrogen production using a Na2S/Na2SO3 aqueous solution under visible light (λ = 450 nm). It was shown for the first time that both kinds of photocatalysts possess high activity in hydrogen evolution under visible light. The solid solution Cd0.65Mn0.35S has an enhanced photocatalytic activity due to its valence and conduction band position tuning, whereas the CdS-β-Mn3O4-MnOOH (40–60 at% Mn) samples were active due to ternary heterojunction formation. Further, the composite CdS-β-Mn3O4-MnOOH photocatalyst had much higher stability in comparison to the Cd0.65Mn0.35S solid solution. The highest activity was 600 mmol g−1 h−1, and apparent quantum efficiency of 2.9% (λ = 450 nm) was possessed by the sample of CdS-β-Mn3O4-MnOOH (40 at% Mn).


2021 ◽  
Author(s):  
Tian-Yun Chen ◽  
Ya-Qi Zhang ◽  
Ying-Yan Fu ◽  
Min Qian ◽  
Hao-Jiang Dai ◽  
...  

Abstract Hydrogen energy is regarded as one of the most important clean energy in the 21st century, and improving the catalytic efficiency of hydrogen evolution reaction (HER) is the basis for realizing the large-scale hydrogen production. Transition metal phosphides (TMPs) were proved to be efficient electrocatalysts for HER. In this work, we first synthesized the nickel-molybdenum bimetallic precursors, followed by high-temperature calcination in air. Finally, NiMoP/MoP nanorods (Ni-Mo-P NRs) was obtained by chemical vapor deposition (CVD) of phosphating. The target catalyst of Ni-Mo-P NRs was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). For Ni-Mo-P NRs, the electrochemical test in 0.5 M H2SO4 solution for HER showed that the optimal feeding ratio was Ni: Mo = 1:1. And the Ni1-Mo1-P NRs presented an onset potential of 63.2 mV, and an overpotential of 117.9 mV was required to drive the current density of 10 mA↔cm− 2. Meanwhile, The Tafel slope, exchange current density (j0), electrochemical double-layer capacitance (Cdl) were 58.6 mV↔dec− 1, 0.10 mA↔cm− 2, 12.6 mF↔cm− 2, respectively. Moreover, there was no obvious activity diminish of Ni1-Mo1-P NRs after a long-term stability and durability test.


2005 ◽  
Vol 20 (2) ◽  
pp. 325-330 ◽  
Author(s):  
Qixun Guo ◽  
Qing Yang ◽  
Lei Zhu ◽  
Chengqi Yi ◽  
Yi Xie

A facile solvothermal approach was successfully developed for the large-scale synthesis of amorphous phosphorus nitride imide (H3xP3N5+x) nanotubes with high luminescent properties by the reaction of 1,3,5-hexachlorotriphosphazene (P3N3Cl6) with sodium amide (NaNH2) at low temperatures. Transmission electron microscope images showed that the inner diameter of nanotubes is 120 ± 20 nm, wall thickness is 40 ± 10 nm, and length ranges from several to ten micrometers. Scanning electron microscope images revealed that the proportion of the nanotubes exceeds 90%. X-ray photoelectron spectroscopy spectra indicated that the binding energies of P2p and N1s are 133.30 and 398.40 eV, respectively, and the atomic ratio of P:N is 3:5.13. The infrared spectra of the sample are comparable to those of the reported HPN2 and HP4N7. Thermogravimetric analysis revealed that the product is very robust in a nonoxidizing atmosphere. The structure and the optical properties of the product and the annealed samples were investigated by x-ray diffraction and photoluminescence measurements, respectively.


RSC Advances ◽  
2016 ◽  
Vol 6 (56) ◽  
pp. 50506-50512 ◽  
Author(s):  
Kaifu Zhang ◽  
Wei Zhou ◽  
Xiangcheng Zhang ◽  
Yang Qu ◽  
Lei Wang ◽  
...  

Stable mesoporous black anatase TiO2 nanosheets (MBTNs) are synthesized via an earth-abundant low-cost biotemplate method combined with an ethanediamine encircling process, and exhibit excellent solar-driven photocatalytic hydrogen generation.


2011 ◽  
Vol 383-390 ◽  
pp. 3188-3191
Author(s):  
Han Jie Huang ◽  
Wen Long She ◽  
Ling Wen Yang ◽  
Hai Peng Huang

A visible-light-responsive TiO2-xNx photocatalyst was prepared by a very simple method. Ammonia solution was used as nitrogen resource in this paper. The TiO2-xNx photocatalyst was characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), UV-Vis diffuse reflection spectra (DRS), and X-ray photoelectron spectroscopy (XPS). The ethylene was selected as a target pollutant under visible light excitation to evaluate the activity of this photocatalyst. The new prepared TiO2-xNx photocatalyst with strong photocatalytic activity under visible light irradiation was demonstrated in the experiment.


2021 ◽  
Author(s):  
Xunliang Hu ◽  
Irshad Hussain ◽  
Bien Tan

Abstract Covalent triazine frameworks (CTFs) have recently been demonstrated as promising materials for photocatalytic water splitting and are usually used in the form of suspended powder. From a practical point of view, immobilized CTFs materials are more suitable for large-scale water splitting applications, owing to their convenient separation and recycling potential. However, existing synthetic approaches mainly result in insoluble and unprocessable powders, which makes their future device application still a huge challenge. Herein, we report an aliphatic amine-assisted interfacial polymerization method to obtain free-standing, crystalline CTFs film with excellent photoelectric performance. The lateral size of the film was up to 250 cm2, the average thickness can be regulated from 30-500 nm. The crystalline structure was confirmed by high-resolution transmission electron microscope (HR-TEM), powder X-ray diffraction (PXRD), and small-angle X-ray scattering (SAXS) analysis. Intrigued by the good light absorption, crystalline structure, and big lateral size of the film, it was immobilized on a glass support that exhibited good photocatalytic hydrogen evolution performance (5.4 mmol h-1 m-2) and was easy to recycle.


2021 ◽  
Vol 11 (5) ◽  
pp. 706-716
Author(s):  
Nada D. Al-Khthami ◽  
Tariq Altalhi ◽  
Mohammed Alsawat ◽  
Mohamed S. Amin ◽  
Yousef G. Alghamdi ◽  
...  

Different organic pollutants have been remediated photo catalytically by applying perovskite photocatalysts. Atrazine (ATR) is a pesticide commonly detected as a pollutant in drinking, surface and ground water. Herein, FeYO3@rGO heterojunction was synthesized and applied for photooxidation decomposition of ATR. First, FeYO 3nanoparticles (NPs) were prepared via routine sol-gel. After that, FeYO3 NPs were successfully incorporated with different percentages (5, 10, 15 and 20 wt.%) of reduced graphene oxide (rGO) in the synthesis of novel FeYO3@rGO photocatalyst. Morphological, structural, surface, optoelectrical and optical characteristics of constructed materials were identified via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), adsorption/desorption isotherms, diffusive reflectance (DR) spectra, and photoluminescence response (PL). Furthermore, photocatalytic achievement of the constructed materials was evaluated via photooxidative degradation of ATR. Various investigations affirmed the usefulness of rGO incorporation on the advancement of formed photocatalysts. Actually, novel nanocomposite containing rGO (15 wt.%) possessed diminished bandgap energy, as well as magnified visible light absorption. Furthermore, such nanocomposite presented exceptional photocatalytic achievement when exposed to visible light as ATR was perfectly photooxidized over finite amount (1.6 g · L-1) from the optimized photocatalyst when illuminated for 30 min. The advanced photocatalytic performance of constructed heterojunctions could be accredited mainly to depressed recombination amid induced charges. The constructed FeYO3@rGO nanocomposite is labelled as efficient photocatalyst for remediation of herbicides from aquatic environments.


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