Observing the catalysts at real-time: the dynamics of ion and mass transfer in the electrocatalytic processes

Supervisor: Dr Zhaojun Han and Scientia Prof Rose Amal

Description:

Hydrogen is widely considered as the ultimate clean energy fuel for automotive as it generates zero greenhouse gas emission during consumption. To produce hydrogen in a sustainable way, water splitting has shown great promise in utilizing renewable electricity from, e.g., solar and wind power. A variety of catalysts (both noble and transition metals) have recently been developed to improve the efficiency of water splitting processes, i.e., the hydrogen evolution reactions (HER) at the cathode side and the oxygen evolution reactions (OER) at the anode side. However, these catalysts often show degradation at prolonged reaction time, increasing the cost and reducing commercial viability. To date, theoretical modelling has been our main tool to understand the electrocatalytic processes on catalysts. Using experimental techniques to observe the ion and mass transport at real-time will thus provide us an extra dimension of understanding with more direct and compelling evidences, thereby leading to the development of more efficient catalyst systems.

This project will use electrochemical quartz crystal microbalance (EQCM) as a powerful technique to investigate the dynamics of ion and mass transport in the electrocatalytic processes. EQCM measures the shift in resonant frequency of quartz crystals, which can then be correlated to the mass change on the surface. As such, the amount of ions inserted into or departed from the catalysts can be probed at a high sensitivity, down to ~1 ng. EQCM has been commonly applied in energy storage devices such as supercapacitors. The project will include

·       the preparation of a range of noble and transition metal catalysts

·       the integration of catalysts on conductive support materials

·       the evaluation of electrocatalytic HER and OER performances

·       the analyses of real-time electrocatalytic processes by EQCM

·       the understanding of electrocatalytic processes combined with theoretical simulations

Suitable for: Chemical Engineers

Level of difficulty: Challenging

Reference

[1] M. D. Levi, N. Levy, S. Sigalov, G. Salitra, D. Aurbach, J. Maier, Electrochemical Quartz Crystal Microbalance (EQCM) Studies of Ions and Solvents Insertion into Highly Porous Activated Carbons, J. Am. Chem. Soc. 2010132, 13220.

[2] W.-Y. Tsai, P.-L. Taberna, P. Simon, Electrochemical Quartz Crystal Microbalance (EQCM) Study of Ion Dynamics in Nanoporous Carbons, J. Am. Chem. Soc. 2014136, 8722.