Tungsten Carbide / Graphene Composite Catalyst
- Details
- Category: Tungsten Information
- Published on Tuesday, 24 October 2017 21:41
Direct methanol fuel cell is a proton exchange membrane fuel cell, which directly uses methanol water solution or steam methanol as fuel to supply power source.
Up to now, the biggest bottleneck of direct methanol fuel cell is its catalyst problem. At present, the methanol oxidation catalyst is still mainly based on platinum Pt, but Pt is expensive and easy to be poisoned by methanol oxidation intermediates, thus affecting the commercialization process of direct methanol fuel cell.
But many people in the study found that the catalytic performance of tungsten is good, but the poor conductivity, which means that WC is not a perfect substitute in platinum status in direct methanol fuel cell, therefore there is a need to find a kind of high conductivity material to solve the problem of conductive tungsten carbide. Only finding cheap catalyst substitutes can find a way out for the development of direct methanol fuel cells. In carbon, graphene (RGO) has good conductivity and unique lamellar structure, is the ideal carrier of the electrocatalysts with vector RGO WC inserted WC-RGO composite material layer prepared has good chemical stability, high conductivity and electrochemical active area of the big advantages.
However, graphene is a single layer of nano scale structure, and it is not so easy to insert tungsten carbide on graphene. Recently, some scholars have pointed out that thiourea can be used to insert highly dispersed WC nanoparticles in a few layers of RGO to form WC-RGO intercalation complex. Thiourea ((NH2) 2CS), as an anion acceptor, has strong ability to bind anions to form stable complexes.
The preparation methods are as follows: firstly, [H2W12O40]6-- (NH2) 2CS-GO precursor is formed by pulling the [H2W12O40]6- onto (NH2) 2CS modified GO; Then, the precursor is reduced to carbonization in a tube furnace, and the precursor reacts to form a single layer of two tungsten sulfide WS2; Because of the single layer structure of two tungsten sulfide, it is easy to react with single layer graphene, WS2-RGO intercalation compound can be obtained, and then WC-RGO intercalation compound is formed by in situ carbonization, tungsten carbide graphene supported platinum electrocatalyst (Pt/WC-RGO) was prepared by microwave assisted method.
The results showed that the average particle size of WC was 1.5 nm and the number of RGO layers was about 5 layers in WC-RGO intercalation complex. In the methanol electro oxidation reaction, compared to the commercial Pt/C catalyst, Pt/WC-RGO intercalation compound catalyst has a higher electrochemical active surface (ECSA) and peak current density and high resistance to CO poisoning and stability are better than Pt/C catalyst. Of course, the most important thing is that the price of composite materials is far lower than platinum, which greatly reduces the cost of electrocatalysts in fuel cells, and is very beneficial to the commercialization of direct methanol fuel cells.
- Tungsten Carbide Manufacturer & Supplier, Chinatungsten Online: tungsten-carbide.com.cn
- Tungsten News & Prices of China Tungsten Industry Association: www.ctia.com.cn
- Molybdenum News & Price: news.molybdenum.com.cn
- Tel.: 86 592 5129696; Fax: 86 592 5129797; Email: sales@chinatungsten.com