Patouossa Issofa - Department of Inorganic Chemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
Nouping Joelle Nadia - Department of Inorganic Chemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
Kenmogne Joseline Flore - Laboratory of Theoretical Chemistry (LCT) and Namur Institute of Structured Matter (NISM), University of Namur, Namur, Belgium
Kamseu Elie - Laboratory of Materials, Local Materials Promotion Authority, MINRESI/MIPROMALO, Yaoundé, , Cameroon
Gouet Bebga - Department of Chemistry, High Teacher Training College, University of Yaoundé I, Yaoundé, Cameroon
Rossignol Sylvie - Institut de Recherche sur les Céramiques, Université de Limoges, Limoges, France
Mbouombouo Ibrahim - Department of Applied Chemistry, Faculty of Science, University of Ebolowa, Ebolowa, Cameroon
Eric Njankwa Njabon - Physical and Theoretical Chemistry Unit, Laboratory of Applied Physical and Analytical Chemistry, Faculty of Science, University of Yaoundé I, P.O. Box ۸۱۲, Yaoundé, Cameroon

This work explores the replacement of Al۳+ by Fe۲+ or Fe۳+ and the effect of porous agent on geopolymers foam formation, using DFT at the level of theory B۳LYP/۶-۳۱G+(d, p). The obtained results show values of HOMO-LUMO gaps that are respectively ۱۳۰.۴۶ ; ۹۳.۳ and ۱۴.۳۸ Kcal.mol-۱ for [Al(OH)۴]-, [Fe(OH)۴]- and [Fe(OH)۴]۲- monomers and; ۶۳.۷۹, ۵.۶۵, ۱۵۵.۵۵ and ۳۶.۱۳ Kcal.mol-۱ for oligomers[(OH)۲Al–(O–Si(OH)۳)۲]- , [(OH)۲Fe–(O–Si(OH)۳)۲]- , [Al–(O–Si(OH)۳)۴]- and Fe–(O–Si(OH)۳)۴]۲-. Calculations using thermodynamics parameter reveals the most favorable porous agent amongst the three (silica fume, aluminum powder and oxygenated water) tested. The results reveal that aluminum powder seems to be the best candidate with the lowest change in G (-۱۹۰.۶۱ Kcal.mol-۱) and S (-۸۲.۹۴ cal/mol.K).

Geopolymers, Foam, porous agent, DFT, HOMO-LUMO gap