skip to content

Yusuf Hamied Department of Chemistry

 
Leah Webster operates an NMR machine.

Leah Webster C@C taken by Michael Webb ©University of Cambridge

Dr Leah Webster is developing catalysts for a more sustainable future.

Leah is a postdoc in the Webster group researching the second most-abundant metal on earth – titanium – and searching for new ways to use it as a catalyst. Titanium is already used as a catalyst in processes like making plastics because of its amazing properties such as its stability and low cost, and Leah wants to push this catalyst’s limits.

Titanium and phosphorus

Titanium catalysts are complemented with phosphine gas which tunes the catalyst’s properties and adds structural support, but these phosphine compounds can be difficult to make. Leah is researching faster, cheaper ways to make phosphine compounds in the laboratory.

Leah explains: “Currently, the main methods for making phosphine compounds generate a lot of waste. They typically start with large, bulky molecules, using the relevant parts and discarding the rest. I want to start
with phosphorous in its simplest form and build the exact molecule we need for cheaper production and to reduce waste.”

Leah is one of the first members to join Dr Ruth Webster’s group since it moved to Cambridge last year (see Issue 67). Ruth adds: “We need new, cost-effective catalysts that replace the rare ones we currently use. My group’s part in a greener future is making catalysts more accessible, especially in industries such as sustainable energy.”

Sustainable catalysts

Catalysts are essential in many chemical reactions but are frequently made of rare metals, such as platinum in car catalytic converters. Acquiring these metals can have significant environmental impacts from mining and may also pose toxicity risks, making them hazardous to handle.

Sustainable catalysts, like the ones Leah is designing, can minimise these problems and be safer and cheaper to use.

“What’s so great about titanium is that it is low cost, really abundant and non-toxic,” says Leah. “Hip replacements are made from titanium, for example, so using titanium is a safe catalyst for many industries, especially for pharmaceutical research.”

Leah recently won a poster prize for this research at the Royal Society of Chemistry Coordination and Organometallic Chemistry Discussion Group conference in 2024.

Pincers

Leah Webster outside the Department of Chemistry.

Leah is continuing her PhD research from Imperial College London where she developed a library of different titanium pincers. A molecular pincer is a claw-shaped molecule that binds tightly to another molecule, usually in two or three places. The tight grip, like a crab claw, makes these molecules useful for making new compounds.

The library was developed as a resource for researchers to discover new transition metal complexes that use titanium as a base.

Leah says: “I met Ruth  when she came to give a talk at Imperial where she explained her work on transition metals and really homed in on earth-abundant metals, mostly iron.

“I had gained extensive experience with titanium during my PhD research and I realised that I could apply the same approach she was using with iron to titanium.”

Leah now uses facilities all over the department from NMR spectroscopy to X-ray diffraction to characterise and uncover the full potential of titanium complexes.

From a small town

Leah grew up in a small town in the English midlands where everyone knew her, so moving to the University of Manchester for her bachelor’s degree was a big change.

“I have an older sister who loves languages and, because she was my role model, I always thought that I would study languages too. Now I speak a little bit of German, but not a lot. Alas!

“It was my physics teacher, Mr Richardson, who suggested I take physics because I love tables and trends and I think the periodic table is a work of art. Later I moved to chemistry because my interests leaned towards chemicals and characterising them.

“My biggest cheerleader is my dad. He has no chemistry experience at all but he still read my entire PhD thesis. He said ‘I don’t understand any of it but it looks really impressive!’”

 

This article was originally published in Chem@Cam magazine Issue 69.