Associate Professor CHUAH Gaik Khuan




B.Sc.(Hons), National University of Singapore, 1982; Ph.D., Texas A&M University, 1987.

Contact Information 

Office: S5-04-03
Tel: (65)-6516-2839 | Fax: (65)-6779-1691
Email: chmcgk@nus.edu.sg


 

ORCID: 0000-0002-4739-9405

ResearcherID: H-8677-2013

 

Research Interests

Our main research area is on heterogeneous catalysis:

  •  Applications of zeolites in fine chemicals synthesis
  •  Green chemistry and catalysis
  •  Synthesis and applications of materials with tunable textural properties
  •  Photocatalysts in water remediation

 

Research Highlight

Zirconium phosphates are used as cation exchangers in the treatment of nuclear wastes and radioactive wastewater, acid catalysts and catalyst supports, intercalation host for drugs and other molecules, fast ion conductors and in chromatography. Zirconium phosphate exists in various crystal structures. In the a-form, planes of zirconium atoms are bridged by phosphate groups which are alternately located above and below the planes. Each zirconium atom is six-coordinated with oxygen atoms from six different phosphate groups. For each phosphate group, three of the oxygen atoms are bonded to three different zirconium atoms while the fourth oxygen atom is protonated. This proton, being exchangeable, gives the material its ion-exchange property with exchange capacity. However, synthesis methodologies to form crystalline a-zirconium phosphate (Zr(HPO4)2·H2O) typically involve the use of excess phosphoric acid, addition of HF or oxalic acid and long reflux times or hydrothermal conditions. We have developed a minimalistic sustainable route using only zirconium oxychloride and concentrated phosphoric acid to form highly crystalline α-zirconium phosphate within hours. The morphology can be changed from platelets to rod-shaped particles. Key features of this minimal solvent synthesis are the excellent yields obtained with high atom economy under mild conditions and ease of scalability.


Teaching Contributions

  • CM3253 Materials Chemistry 1

 

Representative Publications   

  • Cheng, Y.; Wang, X.; Jaenicke, S.; Chuah, G. K. Minimalistic Liquid-Assisted Route to Highly Crystalline a-Zirconium Phosphate. ChemSusChem. 2017, 10, 3235-3242.
  • Yanxiu Gao, Y. X.; Wang, J.; Han, A. J.; Jaenicke, S.; Chuah, G. K. Chemoselective Transfer Hydrogenation of α, β-Unsaturated Carbonyl Compounds Using Potassium Formate Over Amine-Grafted Ru/AlO(OH) Catalysts. Catal. Sci. Technol. 2016, 6, 3806 – 3813.
  • Wang, J.; Okumura, K.; Jaenicke, S.; Chuah, G. K. Post-Synthesized Zirconium-Containing Beta Zeolite in Meerwein-Ponndorf-Verley Reduction: Pros and Cons. Appl. Catal. A. 2015, 493, 112-120.
  • Han, A. J.; Sun, J. L.; Lin, X. H.; Yuan, C.-H.; Chuah, G. K.; Jaenicke, S. Influence of Facets and Heterojunctions in Photoactive Bismuth Oxyiodide. RSC  Adv. 2015, 5, 88298-88305.
  • Fan, A.; Jaenicke, S.; Chuah, G. K. A Heterogeneous Pd-Bi/C Catalyst in the Synthesis of L-Lyxose and L-Ribose from Naturally Occurring D-Sugars. Org. Biomol. Chem. 2011, 9, 7720-7726. [Hot paper].
  • Radhakrishnan, R.; Wu, J. A.; Jaenicke, S.; Chuah, G. K. Effects of Acidity and Pore Size Constraints on Supported Niobium Oxide Catalysts for the Selective Formation of Glycerol Monolaurate. ChemCatChem  2011, 3, 761-770.
  • Radhakrishan, R.; Do, D. M.; Jaenicke, S.; Sasson, Y.; Chuah, G. K. Potassium Phosphate as a Solid Base Catalyst for the Catalytic Transfer Hydrogenation of Aldehydes and Ketones. ACS Catal. 2011, 1, 1631-1636.