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WSe2 Nanostructures Decorated with P...

Ngcobo, Thokozani,

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WSe2 Nanostructures Decorated with Platinum Nanocrystals as Electrocatalysts for Hydrogen Evolution Reaction /

Record Type:	Electronic resources : Monograph/item
Title/Author:	WSe2 Nanostructures Decorated with Platinum Nanocrystals as Electrocatalysts for Hydrogen Evolution Reaction // Thokozani Ngcobo.
Author:	Ngcobo, Thokozani,
Description:	1 electronic resource (106 pages)
Notes:	Source: Masters Abstracts International, Volume: 86-07.
Contained By:	Masters Abstracts International86-07.
Subject:	Materials science. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=31787357
ISBN:	9798346898078

WSe2 Nanostructures Decorated with Platinum Nanocrystals as Electrocatalysts for Hydrogen Evolution Reaction /
Ngcobo, Thokozani,

WSe2 Nanostructures Decorated with Platinum Nanocrystals as Electrocatalysts for Hydrogen Evolution Reaction /Thokozani Ngcobo. - 1 electronic resource (106 pages)

Source: Masters Abstracts International, Volume: 86-07.

Research into tungsten diselenide (WSe2), a two-dimensional layered transition metal dichalcogenide (TMD) material, has increased due to its physical and chemical properties. These properties are considered unique and tunable for targeted applications such as electronic, optical, and catalytic use. WSe2 has comparable bandgap in relation to other selenides which makes it candidate to use as an electrocatalyst for hydrogen evolution reactions (HER). Colloidal synthesis is a cheap, flexible method that allows reaction parameters to be manipulated to influence the desired outcome. Therefore, the effects of concentration, temperature, time, capping agents and tungsten precursors was investigated to find the optimal conditions for the synthesis of WSe2nanoflowers. WSe2nanoflowers were favoured at 320 ⁰C for 120 min in oleyl alcohol when the concentration was 1:4 for W:Se. When the concentration, time and temperature decreased, WSe2favoured nanorod structures. However, when oleylamine was used as a capping agent, agglomeration of the nanoflowers was observed. The metal precursors all favoured oleyl alcohol as the capping agent resulting in defined nanoflowers being formed. The thickness of the nanoflowers varied depending on the precursor used. Tungsten chloride (WCl6) formed densely packed nanoflowers whereas tungsten hexacarbonyl (W(CO)6) and tungstic acid (H2WO4) had less layers forming nanoflower-like structure. H2WO4also produced mixture of WSe2and WO3due to the oxidation of the precursor. The semiconducting 2H phase was obtained from all three tungsten precursors which is required for electrocatalytic activity. To improve the electrocatalytic activity, platinum was decorated on the surface of WSe2. The electrochemical characteristics of Pt/WSe2 nanohybrids formed from various metal precursors were studied using techniques such as linear sweep voltammetry (LSV), cyclic voltammetry (CV), and electrical impedance spectroscopy (EIS). Analysis revealed that W(CO)6-Pt/WSe2 nanohybrids exhibited enhanced electrochemical performance in hydrogen evolution reaction, as evidenced by lower Tafel slope and overpotential at 10mA/cm2, in comparison to the other two precursors.

English

ISBN: 9798346898078Subjects--Topical Terms:

543314
Materials science.
Subjects--Index Terms:

Tungsten diselenide

WSe2 Nanostructures Decorated with Platinum Nanocrystals as Electrocatalysts for Hydrogen Evolution Reaction /
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245 1 0 $a WSe2 Nanostructures Decorated with Platinum Nanocrystals as Electrocatalysts for Hydrogen Evolution Reaction / $c Thokozani Ngcobo.
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300 $a 1 electronic resource (106 pages)
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520 $a Research into tungsten diselenide (WSe2), a two-dimensional layered transition metal dichalcogenide (TMD) material, has increased due to its physical and chemical properties. These properties are considered unique and tunable for targeted applications such as electronic, optical, and catalytic use. WSe2 has comparable bandgap in relation to other selenides which makes it candidate to use as an electrocatalyst for hydrogen evolution reactions (HER). Colloidal synthesis is a cheap, flexible method that allows reaction parameters to be manipulated to influence the desired outcome. Therefore, the effects of concentration, temperature, time, capping agents and tungsten precursors was investigated to find the optimal conditions for the synthesis of WSe2nanoflowers. WSe2nanoflowers were favoured at 320 ⁰C for 120 min in oleyl alcohol when the concentration was 1:4 for W:Se. When the concentration, time and temperature decreased, WSe2favoured nanorod structures. However, when oleylamine was used as a capping agent, agglomeration of the nanoflowers was observed. The metal precursors all favoured oleyl alcohol as the capping agent resulting in defined nanoflowers being formed. The thickness of the nanoflowers varied depending on the precursor used. Tungsten chloride (WCl6) formed densely packed nanoflowers whereas tungsten hexacarbonyl (W(CO)6) and tungstic acid (H2WO4) had less layers forming nanoflower-like structure. H2WO4also produced mixture of WSe2and WO3due to the oxidation of the precursor. The semiconducting 2H phase was obtained from all three tungsten precursors which is required for electrocatalytic activity. To improve the electrocatalytic activity, platinum was decorated on the surface of WSe2. The electrochemical characteristics of Pt/WSe2 nanohybrids formed from various metal precursors were studied using techniques such as linear sweep voltammetry (LSV), cyclic voltammetry (CV), and electrical impedance spectroscopy (EIS). Analysis revealed that W(CO)6-Pt/WSe2 nanohybrids exhibited enhanced electrochemical performance in hydrogen evolution reaction, as evidenced by lower Tafel slope and overpotential at 10mA/cm2, in comparison to the other two precursors.
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650 4 $a Physical chemistry. $3 1981412
653 $a Tungsten diselenide
653 $a Hydrogen evolution reactions
653 $a Cyclic voltammetry
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690 $a 0494
710 2 $a University of the Witwatersrand, Johannesburg (South Africa). $e degree granting institution. $3 3821317
720 1 $a Moloto, Nosipho $e degree supervisor.
720 1 $a Gqoba, Siziwe $e degree supervisor.
773 0 $t Masters Abstracts International $g 86-07.
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792 $a 2023
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