Year of the Periodic Table - Yali Zhou

  • Year: 1st year PhD
  • Supervisor: Dr Jennifer Garden

Yali ZhouTell us about your PhD project

My project combines different fields of chemistry including organometallic synthesis, catalyst development and sustainable polymer materials. My current work focuses on the design and synthesis of new heterometallic (mixed-metal) catalysts for the polymerization of renewable feedstock such as carbon dioxide (CO2). Plastic production is of high energy and environmental concern around the world due to increasingly insecure fossil fuel resources and slow degradation. CO2 is recognized as an ideal alternative carbon source for polymer synthesis because it is inexpensive, renewable, abundant and of low toxicity. The synthesis of polymer materials derived from COhas the potential to achieve the conversion of waste CO2 into value-added products. However, this polymer manufacture is still hampered by the availability of efficient catalysts.

The connectivity between two different metal centres can alter the chemical reactivity of the metal, resulting in new properties such as enhanced catalyst activities compared to their homometallic analogues. However, the significant challenges in the current study are the synthetic issues including the synthesis, purification and characterization of heterometallic catalysts. I feel fortunate to be involved in such a great group that has experience in developing synthetically challenging heterometallic catalysts. I have successfully synthesized and fully characterized the heterometallic complexes, I will test the catalytic reactivity and selectivity under different reaction conditions.

Zinc catalyst in a test tubeWhich element is key to your research area and why?

Zinc. There have been several exciting zinc catalysts designed with high activity and selectivity for the ring-opening copolymerisation of CO2 and epoxides (ROCOP). Considering the environmental issues and cost, zinc is less toxic and cheaper than other metals used in this reaction such as Cr, Co, Al and Mn. Both heterogeneous and homogeneous zinc complexes have been applied to this polymerization reaction. Heterometallic alkaline earth metals such as Mg/Zn systems have recently been reported as catalysts for CO2/epoxide ROCOP and showed excellent catalytic activities that were significantly better than the Zn/Zn analogues. However, very few heterometallic zinc complexes containing alkali metals such as Li, Na, and K have been described so far. Therefore, we decided to focus on these heterometallic catalyst systems.

MacaroonsDescribe your average day of PhD work here in the School of Chemistry

My daily work is spent shuttling between lab and office, doing a lot of synthesis and sorting and analyzing results with various techniques. I also attend some interesting seminars and workshops, meet with my supervisor and participate in the research group meetings as well as interacting with the public engagement team. All these events can inspire me, especially in my research.  One of the most important things in my daily work is expecting and enjoying regular dessert time in our office!

What’s your favourite chemical element?

H (hydrogen). It is the smallest and simplest in the periodic table, but it can release tremendous amounts of energy if the conditions permit.

What's your favourite chemical reaction?

Electrolysis of water: 2 H2O(l) → 2 H2(g) + O2(g)

Water electrolysis can split water into hydrogen and oxygen gases due to the passage of an electric current. Oxygen gas is produced at the anode (oxidation) while hydrogen gas is produced at the cathode (reduction). Electrons flow from the anode to the cathode. This well-established technology has been used for nearly a century for miscellaneous industrial applications (producing chemical feedstocks, cooling power plant generators, fabricating semiconductors, etc.). Recently, it has been considered as a key process that can be used for the production of hydrogen from water and renewable energy sources.