In a recent Nature Chemistry paper, the researchers reveal the mechanism that makes this catalyst more active than regular platinum. By studying how x-ray beams are scattered by the new catalyst, they discovered that the distance between the platinum atoms that are left on the surface of the nanoparticles is less than the distance in pure platinum nanoparticles.
A good catalyst should be able to split up oxygen molecules into atoms but should not bind too strongly with the free atoms; the shorter distance between platinum atoms in the new material makes it a more effective catalyst because it binds even more weakly with the oxygen atoms. There are alternatives to using platinum as a catalyst. Dodelet and his group have worked with General Motors to develop a promising iron-based catalyst that they are now working to commercialize.
Meanwhile, low-cost carbon nanotube catalysts and nickel catalysts are in the works for alkaline fuel-cell chemistries. Platinum-free catalysts have advantages other than their low cost, says Liming Dai , a materials engineering professor at the University of Dayton, in Ohio, who is working on carbon nanotube catalysts.
Platinum nanoparticles tend to lose their catalytic efficiency by aggregating into larger particles over time or when carbon monoxide sticks to their surface. Carbon nanotubes are more robust in the long-term, Dai says.
Strasser agrees that the new catalyst will need further testing. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. SpaceX launches 53 Starlink satellites into orbit 21 hours ago. Nov 12, Methacrylic acid monomers - at what angle they connect with each other in polymer? Nov 09, Is the molecular formula for sugar correct? Nov 03, Is someone out here able to help me name these compounds?
Oct 31, Radioluminescence and differing zinc sulfide preparations? Oct 26, Related Stories. Rough surfaces provide additional sites for energy-generating reactions in fuel cells Jun 08, Sep 16, Jul 18, Lonely atoms, happily reunited Jul 26, Jun 28, Apr 28, Recommended for you.
Polymer discovery gives 3D-printed sand super strength Nov 12, Show: 15 25 50 75 Platinum Catalyst. The ability to prepare well dispersed, high surface area electrocatalysts containing platinum has.. Platinum Black - High Surface Area.
When other molecules stick, the overall electron cloud is changed in shape allowing the stuck molecules to rearrange into new compounds. The catalyst does not change. The rearranged molecules eventually are pushed out by new input ones temperature caused motion and the cycle continues. She says it's a quantum effect. A good catalyst facilitates a reaction at a lower temperature and pressure while not participating in the reaction itself.
Platinum has 4 unpaired electrons in its outermost shell as are the other elements in this group, but this shell is a d orbital which is furthest from the nucleus and very weakly forms molecular bonds. In fact Platinum is at the bottom of the metal reactivity series.
Since its reactivity is so low while its outermost shell is accommodating for weak bonds, it lends itself well as a reaction platform for more strongly bonding reactions. The reactants do temporarily weakly bond to the platinum atom until the other reactant finds the reactant through normal thermal motion and grabs the matching reactant away in a stronger bond leaving the platinum un-bonded.
Think of the lone platinum atom as a match-maker weakly holding reactants until the suitor reactant finds its partner and takes away from platinum matchmaker. Palladium is similar in this regard.
Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Platinum group metals: Why are platinum and palladium great catalysts and not the others? Ask Question.
0コメント