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Synthesis of oxynitride materials for solar water splitting : = investigations with ambient pressure and high pressure synthesis techniques.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Synthesis of oxynitride materials for solar water splitting :/
Reminder of title:	investigations with ambient pressure and high pressure synthesis techniques.
Author:	Dharmagunawardhane, Hingure Arachchilage Naveen.
Description:	1 online resource (107 pages)
Notes:	Source: Dissertation Abstracts International, Volume: 78-08(E), Section: B.
Subject:	Materials science. -
Online resource:	click for full text (PQDT)
ISBN:	9781369614442

Synthesis of oxynitride materials for solar water splitting : = investigations with ambient pressure and high pressure synthesis techniques.
Dharmagunawardhane, Hingure Arachchilage Naveen.

Synthesis of oxynitride materials for solar water splitting :investigations with ambient pressure and high pressure synthesis techniques. - 1 online resource (107 pages)

Source: Dissertation Abstracts International, Volume: 78-08(E), Section: B.

Thesis (Ph.D.)--State University of New York at Stony Brook, 2017.

Includes bibliographical references

Solar water splitting, a photocatalytic process where water is directly split into hydrogen and oxygen using sunlight absorbing semiconductor materials, is one of the most sought after methods to make hydrogen economy a reality. Oxynitrides containing d0 and d10 cations tend to have the appropriate band structure required for solar water splitting. So far, reported efficiencies are not high enough for practical use and synthesizing an oxynitride showing high enough efficiency remains necessary. In this dissertation, we discuss the synthesis of oxynitrides and studying their optical and photocatalytic properties with a particular emphasis on utilizing exploratory high pressure synthesis.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9781369614442Subjects--Topical Terms:

557839
Materials science.
Index Terms--Genre/Form:

554714
Electronic books.

Synthesis of oxynitride materials for solar water splitting : = investigations with ambient pressure and high pressure synthesis techniques.
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100 1 $a Dharmagunawardhane, Hingure Arachchilage Naveen. $3 1187160
245 1 0 $a Synthesis of oxynitride materials for solar water splitting : $b investigations with ambient pressure and high pressure synthesis techniques.
264 0 $c 2017
300 $a 1 online resource (107 pages)
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500 $a Source: Dissertation Abstracts International, Volume: 78-08(E), Section: B.
500 $a Adviser: John B. Parise.
502 $a Thesis (Ph.D.)--State University of New York at Stony Brook, 2017.
504 $a Includes bibliographical references
520 $a Solar water splitting, a photocatalytic process where water is directly split into hydrogen and oxygen using sunlight absorbing semiconductor materials, is one of the most sought after methods to make hydrogen economy a reality. Oxynitrides containing d0 and d10 cations tend to have the appropriate band structure required for solar water splitting. So far, reported efficiencies are not high enough for practical use and synthesizing an oxynitride showing high enough efficiency remains necessary. In this dissertation, we discuss the synthesis of oxynitrides and studying their optical and photocatalytic properties with a particular emphasis on utilizing exploratory high pressure synthesis.
520 $a High pressure synthesis is an interesting route to synthesize oxynitrides as this can stabilize reactants that tend to decompose at ambient pressure, helping to achieve the intended stoichiometry. For synthesis, we selected candidate compositions from published theoretical studies. Reactions were carried out at pressures around 1-3 GPa and at temperatures up to 1300°C in a multi-anvil large volume press. Phase changes were observed with in situ X-ray scattering. In these experiments, we found that most d0 and d10 cations tend to reduce in the high pressure reaction environment as temperature increases, but Zr4+, Hf4+ , and Ta5+ tend to retain their oxidation state. This information will be helpful in future theoretical studies to accurately predict stable oxynitrides synthesizable at high pressure.
520 $a We synthesized (GaN)1--x(ZnO)x solid solution in the entire composition range at 1 GPa, 1150°C. The material showed photocatalytic H2 evolution activity even without surface modification with co catalysts, first such observed for this system. The minimum band gap of 2.65 eV and the highest H2 evolution activity of 2.31 mumol/h were observed at x = 0.51.
520 $a On our initial investigation on the synthesis of gallium oxynitride spinel (Ga3O3N3) at high pressure, we found that the material could be formed by direct ammonolysis of gallium nitrate hydrate at ambient pressure. The formed product was nanocrystalline and exhibited an indirect band gap of 2.5 eV. The material photocatalytically evolved H 2 at an initial rate 8 ?mol/ h, but the activity diminished after five hours due to degradation forming gallium oxide hydroxide.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Materials science. $3 557839
650 4 $a Chemistry. $3 593913
650 4 $a Inorganic chemistry. $3 1182077
655 7 $a Electronic books. $2 local $3 554714
690 $a 0794
690 $a 0485
690 $a 0488
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a State University of New York at Stony Brook. $b Materials Science and Engineering. $3 1187161
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10255628 $z click for full text (PQDT)