Immagine
 Trilingual World Observatory: italiano, english, română. GLOBAL NEWS & more... di Redazione
   
 
\\ Home Page : Articolo
A new catalyst for the so-called hydrogen evolution reaction has been developed by researchers at Stanford University in California.
By Admin (from 21/09/2011 @ 14:00:27, in en - Science and Society, read 1370 times)

The catalyst, which is made of molybdenum disulphide nanoparticles grown on graphene, might be a real alternative to expensive platinum in future large-scale industrial and domestic applications.

Hydrogen could be an environmentally friendly alternative to conventional fossil fuels, particularly if it is electrochemically produced from ordinary seawater – a huge and abundantly available resource. However, before this can happen, scientists need to make advanced catalysts that increase the efficiency of the electrochemical hydrogen reaction (HER). Today, the most efficient HER catalysts are those made from platinum-group metals, but these are expensive.

Now, Hongjie Dai and colleagues have shown that flexible graphene oxide sheets could provide an ideal substrate for MoS2 nanoparticles. The resulting MoS2/reduced graphene oxide hybrid has a very high electrocatalytic activity for the HER that is superior to MoS2 catalysts synthesized without graphene.

 (A) Schematic solvothermal synthesis with GO sheets to afford the MoS2/RGO hybrid. (B) SEM and (inset) TEM images of the MoS2/RGO hybrid. (C) Schematic solvothermal synthesis without any GO sheets, resulting in large, free MoS2 particles. (D) SEM and (inset) TEM images of the free particles. Courtesy: JACS

(A) Schematic solvothermal synthesis with GO sheets to afford the MoS2/RGO hybrid. (B) SEM and (inset) TEM images of the MoS2/RGO hybrid. (C) Schematic solvothermal synthesis without any GO sheets, resulting in large, free MoS2 particles. (D) SEM and (inset) TEM images of the free particles. Courtesy: JACS

Catalytic edge sites

Indeed, the researches have measured a HER "Tafel slope" (which indicates the rate of a electrochemical reaction) of 41 mV/decade – a value that far exceeds the activity of previous MoS2 catalysts. This value results from the large number of catalytic edge sites on the tiny MoS2 nanoparticles and the fact that the material couples well to the underlying graphene network.

And that's not all: the hybrid catalyst also has a small overpotential, a large current density and it remains active even after 1000 cycles. "Traditional catalysts such as platinum and palladium, although very efficient, are pricey," Dai told nanotechweb.org. "Given the performance and low cost of the MoS2/RGO hybrid catalyst reported in our paper, we could foresee a possible replacement of these precious metals in future large-scale industrial and domestic applications."

The Stanford researchers made their hybrid catalysts in a solvothermal reaction of ammonium tetrathiomolybdate – (NH4)MoS4 – and hydrazine in a dimethylformaide solution of graphene oxide at 200 °C overnight. During this process, graphene oxide was reduced to RGO, and (NH4)MoS4 was reduced to MoS2on RGO by hydrazine.

"We are now working on improving our catalyst and possibly integrating it into photoelectrochemical reactions," revealed Dai.

The work was published in the Journal of the American Chemical Society.

Source: NanoTechWeb

Articolo Articolo  Storico Storico Stampa Stampa  Share
Cannabis seeds, Autoflowering seeds, Greenhouse, Sweet Seeds, Dutch Passion
comments powered by Disqus
 
Nessun commento trovato. No comments found. Nici un comentariu găsit.

Anti-Spam: dial the numbers CAPTCHA
Text (max 5000 characters)
Nome - Name - Nume
Link ( OPTIONAL - visible on the site - NOT a must )


Disclaimer
Tuo commento sarŕ visibile dopo la moderazione. - Your comment will be visible after the moderation. - Comentariul tău va fi vizibil după moderare.
Ci sono 1548 persone collegate

< luglio 2019 >
L
M
M
G
V
S
D
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
       
             

Titolo
en - Global Observatory (605)
en - Science and Society (594)
en - Video Alert (346)
it - Osservatorio Globale (503)
it - Scienze e Societa (555)
it - Video Alerta (132)
ro - Observator Global (399)
ro - Stiinta si Societate (467)
ro - TV Network (149)
z - Games Giochi Jocuri (68)

Catalogati per mese - Filed by month - Arhivate pe luni:

Gli interventi piů cliccati

Ultimi commenti - Last comments - Ultimele comentarii:
Hi, it's Nathan!Pretty much everyone is using voice search with their Siri/Google/Alexa to ask for services and products now, and next year, it'll be EVERYONE of your customers. Imagine what you are ...
15/01/2019 @ 17:58:25
By Nathan
Now Colorado is one love, I'm already packing suitcases;)
14/01/2018 @ 16:07:36
By Napasechnik
Nice read, I just passed this onto a friend who was doing some research on that. And he just bought me lunch since I found it for him smile So let me rephrase that Thank you for lunch! Whenever you ha...
21/11/2016 @ 09:41:39
By Anonimo


Titolo

Latest NEWS @
www.TurismoAssociati.it

Non-Hodgkin lymphoma cured by CANNABIS. The video of Stan and Barb Rutner.

Dr. Joycelyn Elders, U.S. surgeon general: Myths About Medical Marijuana in The Providence Journal, 2004.

Marihuana vindeca CANCERUL: marturii despre uleiul de cocos si canabis.

Yahoo Incorporated Mail. My account recovery information is incorrect. The Password Helper says my password can't be reset online. "First time signing in here?" message.

All information in a video about Donatio Mortis Causa and The Venus Project

What is TOR browser?

Wells Fargo posts higher profit on cost controls, rise in loans

Goldman Sachs profit beats estimates, boosted by strong equities trading

No federal charges for New York police officer in Eric Garner death: source

Iran to give no quarter in stand-off with U.S.: supreme leader

Amazon offers $10 to Prime Day shoppers who hand over their data

U.S. retailers gain online shoppers on Amazon's Prime Day: Adobe

Ultimele articole - Antena3.roLe-a spus medicilor ca ceva nu în regula cu corpul ei ?i ca se simte bolnava, dar ei i-au transmis doar ca e stresata. Dupa doar doua luni ?i-a parasit familia pentru totdeauna din cauza cancerului

Soferul masinii în care se afla Razvan Cuc a ramas fara permis în urma accidentului din Capitala

El este preotul ortodox acuzat de pornografie infantila. Ce a putut sa trimita pe Facebook parintele

eMAG reduceri la cuptoare si plite incorporabile, de Stock Busters

O vedeta pe Instagram, ucisa de iubitul ei. Barbatul a fost gasit înjunghiat în gât, dupa cumplitul incident

Cine face recuperare de creante si cum iti poate ajuta compania?





16/07/2019 @ 16:43:11
script eseguito in 812 ms