Killing Two Birds With One Stone — Week 8 at Stanford Chemical Engineering

Apr 19, 2019

Hi everyone!

It’s Ethan, back again to tell you about my adventures at the Shriram Center for Chemical Engineering and Bioengineering at Stanford! This week, since Zeus had been down for a while, Angel and I decided to proceed with a completely new side project.

Based on my experimental results from previous weeks, I found out that when catalytic platinum nanoparticles are put into contact with tungsten oxide, the catalyst’s activity is improved tremendously. So far, all the catalysts I had been synthesizing had consisted of small platinum nanoparticles deposited onto much larger chunks of tungsten-oxide-containing support material. This worked great — however, recently, Angel discovered some literature that suggested that the activity might be increased even more by increasing the size of the platinum particles. The only problem with synthesizing large particles is that as the size of the particle increases, more and more of the platinum becomes contained on the inside of the particle, meaning it is not exposed to the surface and therefore does not contribute whatsoever to the catalytic activity. Platinum is expensive! So it would be a shame if all that platinum on the inside were put to waste! To remedy this issue, what some researchers have tried to do is to synthesize particles where all the non-surface platinum is replaced with a cheaper, inert material, hoping that the difference would not be noticed in the catalytic activity (since catalytic mechanisms can only happen at the surface!). This effectively creates a sort of “core-shell” structure, with some core material being encapsulated by a platinum shell. What Angel and I thought we could do was the following: since past experiments have shown that tungsten seems to benefit the platinum’s activity tremendously, we thought of synthesizing a core-shell structure consisting of a tungsten core surrounded by a platinum shell. This would give us the benefit of the tungsten-platinum synergy¬†as well as the benefits of larger platinum particles! Killing two birds with one stone!

Angel did some digging — nobody has done this specific synthesis before, but she did find a paper in which researchers synthesized a tungsten-carbide core encapsulated by gold nanoparticles. So, we decided that we would model our experiment after this paper.

I have begun the steps of this synthesis, and they shall be discussed in a future blog post.

~Ethan Y. Feng

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