1. Department of Chemical Sciences University of Johannesburg Doornfontein 2028 South Africa
2. Centre for Nanostructures and Advanced Materials DSI‐CSIR Nanotechnology Innovation Centre Council for Scientific and Industrial Research Pretoria 0001 South Africa
3. Department of Chemistry College of Natural Science Yeungnam University 280 Daehak‐Ro, Gyeongsan Gyeongbuk 38541 Republic of Korea
4. Particulate Matter Research Center Research Institute of Industrial Science & Technology (RIST) 187‐12, Geumho‐ro, Gwangyang‐si Jeollanam‐do 57801 Republic of Korea