1. Department of Chemistry, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
2. Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute, University of Nottingham Ningbo China, Ningbo 315100, People’s Republic of China
3. Faculty of Science, Laboratory of Nanomaterial for Sensors and Energy, University of Yaounde I, Yaoundé B.P. 812, Cameroon
4. Department of Chemistry, Maseno University, P.O. Box, 333-40105, Maseno, Kenya
5. School of Pure and Applied Sciences, Bomet University College, P.O. Box 701-20400, Bomet, Kenya
6. School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK