Research projects in the Cheah group
Biomimetic self-assembly of artificial water oxidation catalysts
The focus of this project is the design and synthesis of peptide ligands on electrode surface that promote self-assembly of water oxidation catalysts. The approach is inspired by the oxygen evolving complex in photosystem II, where the Mn4CaO5 cluster self-assemble under operating conditions in the apo-form of photosystem II.
Improving substrate specificity of CO2 reduction catalysts
To achieve electrolytic CO2 reduction by direct air capture, a key unresolved problem is the specificity of catalysts towards CO2 or O2 reduction. Reduction of O2 is thermodynamically favorable and the abundance of CO2 (0.04%) is significantly lower compared to O2 (21%) in the atmosphere. As such, current generation of CO2 electrolyser operates under strict exclusion of O2, thus increasing cost. We are conducting research towards understanding how to control CO2 specificity of molecular catalysts to operate in presence of O2.
Redox chemistry of metal carbonyl and cyanometallate complexes
Metal carbony and cyanometallate complexes have rich redox chemistry and exhibit catalytic H+, CO2 or O2 reduction activity. We study the redox chemistry of metal carbonyl and cyanometallate complexes by combination of DFT, FTIR and XAS spectroelectrochemistry.
Photosystem II research
We study the mechanism of water oxidation by photosystem II, with specific emphasis on the identifying the substrate identity and binding sites at all semi-stable intermediate states of the Kok cycle. We are developing techniques to measure 18O/16O ratio of the substrates using membrane inlet mass spectrometry. Together with our international collaborators, we conduct time resolved XFEL crystallography studies on PSII to understand the mechanism of water oxidation and conduct kinetic studies on photoactivation of PSII using membrane inlet mass spectrometry.