scholarly journals Role of the Sulphur Source in the Solvothermal Synthesis of Ag-CdS Photocatalysts: Effects on the Structure and Photoactivity for Hydrogen Production

Hydrogen ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 64-89
Author(s):  
Erika Soto Morillo ◽  
Noelia Mota Toledo ◽  
Jose Luisa García Fierro ◽  
Rufino M. Navarro Yerga
Keyword(s):  
Hydrogen Production ◽  
Solvothermal Synthesis ◽  
Nucleation And Growth ◽  
Elemental Sulphur ◽  
Confinement Effect ◽  
Generation Rate ◽  
Sulphur Source ◽  
Crystalline Domains ◽  
Strong Confinement

The aim of this work is to study the influence of the sulphur source (elemental sulphur, thiourea and L-cysteine) in the solvothermal synthesis of Ag-CdS over its growth, structuration and state of Ag and how these changes influence on its photoactivity. The differences in the generation rate of the S2− from the sulphur sources during the solvothermal synthesis determine the nucleation and growth pathways of CdS affecting to the silver state and its incorporation into the CdS lattice. The hydrogen production on Ag-CdS photocatalysts decreases according the sequence: thiourea > elemental sulphur >> L-cysteine. The changes in the photoactivity of Ag-CdS samples are analysed in terms of the differences in the insertion of Ag+ into the CdS lattice, the formation of composites between CdS and Ag2S and the formation of CdS crystalline domains with strong confinement effect derived from the different sulphur source used in the solvothermal synthesis.

scholarly journals CdS Photocatalysts Modified with Ag: Effect of the Solvothermal Temperature on the Structure and Photoactivity for Hydrogen Production

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 110 ◽  
Author(s):  
Erika Soto ◽  
Fernando Vaquero ◽  
Noelia Mota ◽  
Rufino Manuel Navarro ◽  
Jose Luis G. Fierro
Keyword(s):  
Low Temperature ◽  
Hydrogen Production ◽  
Solvothermal Synthesis ◽  
Chemical State ◽  
Confinement Effect ◽  
Cds Nanostructures ◽  
Strong Confinement ◽  
Metallic Species ◽  
Low Crystallinity

This work studies the effect of the temperature in the solvothermal synthesis of CdS modified with Ag (Ag-CdS) over both the structure of CdS and the chemical state of the Ag species. The increase in the solvothermal temperature produces the evolution of the CdS nanostructures from nanoparticles of low crystallinity in coexistence with small nanocrystals with strong confinement effect to the formation of highly crystalline nanorods. The Ag species also change with the solvothermal temperature from Ag2S species, formed at low temperature, to metallic species as the temperature increases. The photoactivity of the Ag-CdS samples is the result of the combination of three factors: crystallinity of the CdS structures, existence of small nanocrystals with strong confinement effect and the presence of segregated Ag2S species. The Ag-CdS sample prepared at 120 °C shows the better efficiency for hydrogen production because it achieves the better combination of the aforementioned factors

ROLE OF FLOW AND MASS TRANSFER IN PHOTOBIOREACTOR: FROM BACTERIA LOCOMOTION TO HYDROGEN PRODUCTION

2018 ◽  
Author(s):  
Xun Zhu ◽  
Qiang Liao ◽  
Rong Chen ◽  
Ao Xia ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Hydrogen Production

Sewage sludge as a precursor of adsorbents/catalysts for environmental applications

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
A. Ros ◽  
C. Canals-Batlle ◽  
M.A. Lillo-Ródenas ◽  
E. Fuente ◽  
M. A. Montes-Morán ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Room Temperature ◽  
Waste Water Treatment ◽  
Textural Properties ◽  
Active Species ◽  
Elemental Sulphur ◽  
Gaseous Emissions ◽  
Removal Experiments ◽  
Catalytically Active

This paper focuses on the valorisation of solid residues obtained from the thermal treatment of sewage sludge. In particular, sewage sludge samples were collected from two waste water treatment plants (WWTPs) with different sludge line basic operations. After drying, sludges were heated up to 700 °C in appropriate ovens under diluted air (gasification) and inert (pyrolysis) atmospheres. The solids obtained, as well as the dried (raw) sludges, were characterised to determine their textural properties and chemical composition, including the speciation of their inorganic fraction. All the materials under study were employed as adsorbents/catalysts in H2S removal experiments at room temperature. It was found that, depending on the particular sludge characteristics, outstanding results can be achieved both in terms of retention capacities and selectivity. Some of the solids outperform commercially available sorbents specially designed for gaseous emissions control. In these adsorbents/catalysts, H2S is selectively oxidised to elemental sulphur most likely due to the presence of inorganic, catalytically active species. The role of the carbon-enriched part on these solids is also remarked.

Hot injection induced synthesis of ZnCdS-rGO/MoS2 heterostructures for efficient hydrogen production and CO2 photoreduction

2021 ◽  
Author(s):  
Amit Gautam ◽  
Saddam Sk ◽  
Amritanjali Tiwari ◽  
Moses Abraham Bokinala ◽  
P. Vijayanand ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Generation Rate ◽  
Co2 Photoreduction ◽  
H2 Generation ◽  
Highly Efficient ◽  
Hot Injection ◽  
And Control

A highly efficient hybrid ZnCdS-rGO/MoS2 heterostructure is successfully synthesized through a hot injection approach and control loading of rGO/MoS2. The synergism provides an unprecedently high H2-generation rate 193.4 mmol H2...

scholarly journals Study of Nucleation and Growth in the Organometallic Synthesis of Magnetic Alloy Nanocrystals: The Role of Nucleation Rate in Size Control of CoPt3 Nanocrystals.

ChemInform ◽  
2003 ◽  
Vol 34 (42) ◽  
Author(s):  
Elena V. Shevchenko ◽  
Dmitri V. Talapin ◽  
Heimo Schnablegger ◽  
Andreas Kornowski ◽  
Oerjan Festin ◽  
...  
Keyword(s):  
Nucleation Rate ◽  
Size Control ◽  
Nucleation And Growth ◽  
Magnetic Alloy ◽  
Organometallic Synthesis ◽  
Alloy Nanocrystals

Preferred Orientations for Sol-Gel Derived Plzt Thin Layers

1993 ◽  
Vol 310 ◽  
Author(s):  
Toshihiko Tani ◽  
Zhengkui Xu ◽  
David A. Payne
Keyword(s):  
Heat Treatment ◽  
Surface Energy ◽  
Sol Gel ◽  
Nucleation And Growth ◽  
Thin Layers ◽  
Energy Conditions ◽  
Chemical Characteristics ◽  
Interfacial Chemistry ◽  
Si Substrates

AbstractPLZT thin layers were deposited onto various substrates by sol-gel methods, and crystallized under different conditions and substrate treatments. Relationships are given for the chemical characteristics of the substrate's surface and the preferred orientations which develop on heat treatment. A preferred (111) orientation always developed for perovskite crystallized on Pt layers which contained Ti on the surface. This was attributed to the formation of Pt3Ti and the role of heteroepitaxial nucleation and growth sites. In addition, a preferred (100) orientation was also obtained on unannealed Pt/Ti/SiO2/Si substrates which were free of Ti on the surface. This was attributed to self-textured growth with flat faces striving for minimum surface energy conditions. The results are discussed in terms of the importance of interfacial chemistry on the control of texture for crystallization of PLZT thin layers on coated substrates.

Role of Iron Concentration on Hydrogen Production Using Confectionery Wastewater

2016 ◽  
Vol 142 (9) ◽  
Author(s):  
M. K. Yogeswari ◽  
K. Dharmalingam ◽  
P. Ronald Ross ◽  
P. Mullai
Keyword(s):  
Hydrogen Production ◽  
Iron Concentration

scholarly journals The role of graphene/graphene oxide in cement hydration

2021 ◽  
Vol 10 (1) ◽  
pp. 768-778
Author(s):  
Shaoqiang Meng ◽  
Xiaowei Ouyang ◽  
Jiyang Fu ◽  
Yanfei Niu ◽  
Yuwei Ma
Keyword(s):  
Graphene Oxide ◽  
Cement Paste ◽  
Cement Hydration ◽  
Isothermal Calorimetry ◽  
High Mobility ◽  
Nucleation And Growth ◽  
Early Hydration ◽  
Mobility Of Ions ◽  
Cement Surface

Abstract Graphene (G) and graphene oxide (GO) have been shown to significantly improve the mechanical properties of cement-based materials. In this study, the effect of the G/GO on cement hydration was investigated. First, the zeta potential of G/GO in simulated solutions was tested, and the interaction between G/GO’s surface and Ca2+ was explored. Subsequently, scanning electron microscopy was used to observe the morphology of C–S–H nucleation and growth on the cement surface in the cement paste containing G/GO. Furthermore, XRD and TGA analyses were carried out on the hydration products of the sample. At last, isothermal calorimetry was applied to investigate the influence of G/GO on the early hydration of cement. The results showed that the addition of G/GO significantly accelerates C–S–H nucleation and growth on the cement surface. It is indicated that the high mobility ions derived by G/GO in the cement paste dominate the reason for the accelerated hydration of cement. The presence of G, especially GO, facilitates the mobility of ions, especially Ca2+, thus enhances the interaction between the cement surface and the ions. This strong interaction promotes the C–S–H nucleation and growth, and therefore, the hydration of the cement.

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