1. Departamento de Ingeniería Química, University of Alicante, Apartado 99, Alicante E-03080, Spain
2. Institute for the Development of Energy for African Sustainability (IDEAS), College of Science, Engineering and Technology, University of South Africa (UNISA), c/o Christiaan de Wet & Pioneer Avenue, Florida Campus, 1710 Johannesburg, South Africa
3. African Energy Leadership Centre, Wits Business School, & Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Private Bag 3, PO WITS, 2050 Johannesburg, South Africa