Mahmoud Adel Hamza, Gregory Metha, Cameron Shearer
Department of Chemistry, School of Physics, Chemistry & Earth Sciences, University of Adelaide, Adelaide, SA, 5005, Australia
Ra was the Ancient Egyptian god of the sun, and ancient Egyptians relied on solar energy in many aspects of daily life. Solar bread provides a simple example of how sunlight transforms basic ingredients into value-added products. Inspired by this concept, we aim to “hit two birds with one stone” by harnessing abundant solar energy through photocatalysis to simultaneously produce renewable fuels, valorise waste streams, and remediate environmental contaminants.(Qi et al., 2021; Hamza, Metha and Shearer, 2025) Visible-light-active metal indium sulfides (MIn2S4, M= Cd, Zn) were synthesised and investigated as multifunctional photocatalysts. In the first project, CdIn2S4-based photocatalysts were used for the simultaneous production of hydrogen and valorisation of biomass-derived furfuryl alcohol into furfural, a high-value platform chemical widely used in the fine chemical and pharmaceutical industries. Metal modification significantly enhanced charge separation, hydrogen evolution, substrate conversion, and product selectivity. (Hamza et al., 2024) In a second project, CdIn2S4-based materials were employed for the photocatalytic valorisation of benzylamine into value-added nitrogen-containing heterocyclic compounds while concurrently producing hydrogen fuel. The photocatalyst composition strongly influenced product distribution, demonstrating opportunities for selective solar-driven organic synthesis.(Hamza et al., 2026a) In a third project, CdIn2S4 and ZnIn2S4 were investigated for the photoreductive degradation of per- and polyfluoroalkyl substances (PFAS), a class of highly persistent contaminants commonly known as “forever chemicals”. (Hamza et al., 2025, 2026b) Both photocatalysts demonstrated efficient degradation of perfluorooctanesulfonic acid (PFOS), accompanied by extensive defluorination and fluoride ion formation, confirming cleavage of the highly stable C–F bonds. Mechanistic investigations identified photoexcited electrons as the primary
reactive species driving PFOS destruction. Importantly, CdIn2S4 and ZnIn2S4 exhibited visible-light activity and achieved high mineralisation of both pure PFOS solutions and complex field-derived PFAS samples. Collectively, these studies demonstrate the potential of Ra-inspired photocatalysis as a sustainable platform for integrating renewable fuel production, waste valorisation, and environmental remediation within a circular chemical economy.
References
Hamza, M. A. et al. (2024) ‘Ultrathin Ru-CdIn2S4 nanosheets for simultaneous photocatalytic green hydrogen production and selective oxidation of furfuryl alcohol to furfural’, Chemical Engineering Journal, 493, p. 152603. doi: 10.1016/j.cej.2024.152603.
Hamza, M. A. et al. (2025) ‘CdIn2S4 Micro‐Pyramids for Reductive Photocatalytic Degradation of Perfluorooctanesulfonic Acid’, Small, 21(36), p. e04601. doi: 10.1002/smll.202504601.
Hamza, M. A. et al. (2026a) ‘Post‐Addition of Metal Species over CdIn2S4 Micro‐Pyramids/Nanosheets for Photocatalytic Hydrogen Production and Benzylamine Valorization’, Solar RRL, 10(7), p. To be Submitted Manuscript. doi: 10.1002/solr.202500933.
Hamza, M. A. et al. (2026b) ‘Photocatalytic reductive degradation of perfluorooctanesulfonic acid using ZnIn2S4 with mechanistic insights’, submitted to Small (under 2nd review), p. 2026.
Hamza, M. A., Metha, G. F. and Shearer, C. J. (2025) ‘Recent advances and future directions of CdIn2S4-based photocatalysts: properties, synthesis, and modifications for energy and environmental applications’, Journal of Materials Chemistry A, 13(27), pp. 21292–21351. doi: 10.1039/D5TA02047F.
Qi, M. Y. et al. (2021) ‘Cooperative Coupling of Oxidative Organic Synthesis and Hydrogen Production over Semiconductor-Based Photocatalysts’, Chemical Reviews, 121(21), pp. 13051–13085. doi: 10.1021/acs.chemrev.1c00197.