scholarly journals Tailoring Noble Metal-Free Ti@TiO2 Photocatalyst for Boosting Photothermal Hydrogen Production

2021 ◽  
Vol 1 ◽  
Author(s):  
Sara El Hakim ◽  
Tony Chave ◽  
Amr A. Nada ◽  
Stéphanie Roualdes ◽  
Sergey I. Nikitenko

In this work, we provide new insights into the design of Ti@TiO2 photocatalyst with enhanced photothermal activity in the process of glycerol reforming. Ti@TiO2 nanoparticles have been obtained by sonohydrothermal treatment of titanium metal nanoparticles in pure water. Variation of sonohydrothermal temperature allows controlling nanocrystalline TiO2 shell on Ti0 surface. At 100 < T < 150°C formation of TiO2 NPs occurs mostly by crystallization of Ti(IV) amorphous species and oxidation of titanium suboxide Ti3O presented at the surface of Ti0 nanoparticles. At T > 150°C, TiO2 is also formed by oxidation of Ti0 with overheated water. Kinetic study highlights the importance of TiO2 nanocrystalline shell for H2 generation. Electrochemical impedance spectroscopy points out more efficient electron transfer for Ti@TiO2 nanoparticles in correlation with photocatalytic data. The apparent activation energy, Ea = (25–31) ± 5 kJ·mol−1, assumes that photothermal effect arises from diffusion of glycerol oxidation intermediates or from water dynamics at the surface of catalyst. Under the heating, photocatalytic H2 emission is observed even in pure water.

2018 ◽  
Vol 115 (17) ◽  
pp. 4345-4350 ◽  
Author(s):  
Bin Tian ◽  
Bining Tian ◽  
Bethany Smith ◽  
M. C. Scott ◽  
Qin Lei ◽  
...  

Few-layer black phosphorus (BP) nanosheets were first reported as a 2D material for the application of field-effect transistors in 2014 and have stimulated intense activity among physicists, chemists, and material and biomedical scientists, driving research into novel synthetic techniques to produce BP nanosheets. At present, exfoliation is the main route toward few-layer BP nanosheets via employing bulk BP as raw material. However, this is a complicated and time-consuming process, which is difficult for the large-scale synthesis of BP nanosheets. Moreover, BP degrades rapidly when exfoliated to nanoscale dimensions, resulting in the rapid loss of semiconducting properties. Here, we report the direct wet-chemical synthesis of few-layer BP nanosheets in gram-scale quantities in a bottom-up approach based on common laboratory reagents at low temperature, showing excellent stability due to partial oxidation of surface. Solvent and temperature are two critical factors, controlling not only the formation of BP nanosheets but also the thickness. The as-prepared BP nanosheets can extract hydrogen from pure water (pH = 6.8), exhibiting more than 24-fold higher activity than the well-known C3N4 nanosheets. Our results reporting the ability to prepare few-layer BP nanosheets with a facile, scalable, low-cost approach take us a step closer to real-world applications of phosphorene including next-generation metal-free photocatalysts for photosynthesis.


2015 ◽  
Vol 17 (23) ◽  
pp. 15428-15434 ◽  
Author(s):  
P. Ben Ishai ◽  
S. R. Tripathi ◽  
K. Kawase ◽  
A. Puzenko ◽  
Yu. Feldman

We present evidence that the microscopic origin of both the excess wing and the main relaxation process of pure water is the same.


2019 ◽  
Vol 9 (4) ◽  
pp. 966-973 ◽  
Author(s):  
Yuhei Yamamoto ◽  
Makoto Fukui ◽  
Atsuhiro Tanaka ◽  
Keiji Hashimoto ◽  
Hiroshi Kominami

A TiO2 modified with 2,3-dihydroxynaphthalene responds to visible light, and electrons are photogenerated to the CB of TiO2 under light irradiation in the presence of a suitable hole scavenger.


2019 ◽  
Vol 3 (12) ◽  
pp. 3375-3386 ◽  
Author(s):  
Andrea Baricci ◽  
Andrea Bisello ◽  
Alexey Serov ◽  
Madeleine Odgaard ◽  
Plamen Atanassov ◽  
...  

A simple approach based on electrochemical impedance spectroscopy measurement is adopted to elucidate the effect of mixed ion and electron transport limitations during materials aging in platinum group metal-free catalysts for PEMFC.


RSC Advances ◽  
2016 ◽  
Vol 6 (50) ◽  
pp. 43950-43953 ◽  
Author(s):  
Ben-Quan Hu ◽  
Jie Cui ◽  
Li-Xia Wang ◽  
Ya-Lin Tang ◽  
Luo Yang

Here we report that an excess amount of aldehyde, in particular, aliphatic aldehyde, without any additives, efficiently facilitates the oxidation of aminal intermediates to quinazolinones in pure water.


2008 ◽  
Vol 396-398 ◽  
pp. 381-384 ◽  
Author(s):  
Eduardo Mioduski Szesz ◽  
Cláudia E. B. Marino ◽  
Haroldo A. Ponte ◽  
Fabiana C. Nascimento ◽  
Carlos M. Lepienski ◽  
...  

Although titanium metal has been used intensively in the last years as biomaterial in the medical and dental areas its surface is not bioactive. In this work, titanium metal was submitted to an alkali treatment in order to make the metal surface bioactive. The samples were submitted to alkaline treatment (AT) using NaOH 5M aqueous solution at 60°C for 24 h and after that they were heated thermically to stabilize the layer obtained with AT. The bioactivity of the samples was evaluated soaking them into the simulated body fluid (SBF) at 36,5°C for 28 days. The morphological, structural changes and the electrochemical characterization were analyzed using scanning electron microscopy, x-ray diffraction and electrochemical impedance spectroscopy (EIS), respectively. It was verified that after AT plus heat treatment (HT) a sodium titanate layer was formed on the samples surface and after the bioactivity tests an apatite layer was formed. Impedance analysis show that the resistance of film on Ti is high and this value increases when the sample is soaked in SBF. It means that the apatite (HPA) film is occurring and the value of the capacitance with the presence of the HPA film (Cp) values indicate that the film maintain a compact and uniform characteristics.


Author(s):  
Igor Jerman ◽  
Vesna Periček Krapež

Introduction Homeopathy, at least in its UHD aspect, proves that the biological function of molecules (their “message”) can be transmitted from some original material substance through pure water to living systems (1). Even if in general this transmission is based on serial dilutions of mother tinctures, experiments demonstrate it can be realized also via modified environmental EM fields, i.e. through the air as is known from the experiments performed by Montagnier (2), Endler and our group (3). It is also known as electronic homeopathy and is capable of a very similar achievement to UHD homeopathy without any chemical continuity between mother tincture and the final informed water. Quantum field theory developed by Preparata and Del Giudice brings theoretical ground to understanding and explaining this, for contemporary physicists, seemingly impossible phenomenon (4). Namely, it is not only that molecular information can be transmitted and stored in pure (UHD) water, but also that it can provoke changes in organisms. Theoretical model According to quantum electrodynamics, the interactions between an original substance, water and an organism are enabled by coherent domains (CDs). Many experiments corroborate the capacity of CDs to get entangled (phase locking) with the complex field of mother tincture’s substance(s) and consequently to encode the message of the tincture. However this is not the end of the process; this code must later be decoded from the side of the organism (and it seems that it can be even decoded by chemical systems, according to Elia (5)) and make an appropriate reaction. We assume that in case of organisms the endogenous coherent EM field first proposed by Fröhlich is responsible for the decoding; however a homeostatic energy barrier must be broken. Many experiments confirm that even physiological states, not only chemical messages ((6, 7) can be transmitted through the same channel. The language of CDs and other EM coherent modes is not violent – the message of a molecule is presented in a way that provokes a reaction but cannot force the organism into a pathological or dead state. Therefore we can speak of a subtle (bio)chemistry and pharmacology, based on coherent modes and using a universal common language understandable to molecules and organisms. Conclusion  Chemicals, water coherent domains, endogenous coherent oscillations of organisms and physiological responses must share a common denominator;  quantum field oscillations and their wave structures could represent the denominator and therefore the active molecular information;  potentization somewhat sharpens these wave structures, gives them more penetrative power, which makes higher potencies (dilutions) generally more effective – as they must break the homeostatic barrier of organismic endogenous EM field.  understanding the language implied in the first point as well as deeper mechanisms of sharpening the molecular information will enable us to enter a new era of subtle (bio)chemistry and pharmacology, surpassing not only contemporary pharmaceutical practice, but also the homeopathic one. References [1] P. Bellavite, M. Marzotto, D. Olioso, E. Moratti, A. Conforti, High-dilution effects revisited. 1. Physicochemical aspects. Homeopathy. 103(1):4-21 (2014). [2] Monatagnier et al., DNA waves and water, arXiv:1012.5166v1 [q-bio.OT] (2010). [3] I. Jerman, R. Ružič, R. Krašovec, M. Škarja, L. Mogilnicki, Electrical transfer of molecule information into water, its storage and bioeffects on plants and bacteria. Electromagnetic Biology and Medicine. 24(3): 341-354 (2005). [4] E. Del Guidice, P. R. Spinetti, A. Tedeschi, Water Dynamics at the Root of Metamorphosis in Living Organisms. Water. 2010, 2, 566-568; doi:10.3390/w2030566. [5] Elia V. in Niccoli M. 1999. Thermodynamics of extremely diluted aqueous solutions. Annals of the New York Academy of Sciences, 879: 241-248. [6] C. W. Smith, Quanta and Coherence Effects in Water and Living Systems. The Journal of Alternative and Complementary Medicine. 10(1):69-78. (2004). [7] A. Foletti, J. Pokorny, Biophysical approach to low back pain: a pilot report. Electromagnetic Biology and Medicine. 34 (2): 156-159 (2015).


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