abstract
For the first time, highly porous ZnO-based biomorphic materials were synthesised using cork as a natural sustainable template. In the first step, waste cork powder was pyrolysed and converted into inorganic carbon. This template was then infiltrated using a novel approach employing an aerosol of zinc-containing solutions. The infiltrated powders were calcined to convert the precursors into zinc oxide. Depending on temperature, these could form either a ZnO-graphite composite material, or pure ZnO. Their morphology, porosity, microstructure and composition were characterised; their optical band gap energies, ability to adsorb and photodegrade organic pollutants and UV absorption were also assessed. When heated to 350 degrees C they maintained the 3D porous cork structure, producing a graphite-containing composite material, with both physical adsorption and photocatalytic activity (E-g = 3.19 eV), suitable for environmental remediation. When heated to 700 degrees C, the powders were pure ZnO (no graphite), and they absorbed in the UV region, hence suitable for use as sunscreen. Doped ZnO ecoceramics were also produced, using silver and aluminium. An addition of 1 mol% Ag improved photocatalysis under solar light. Conversely, adding 2 mol% Al and calcining at 700 degrees C deactivated photocatalysis, but maintained strong UV absorption, producing a safer sunscreen material (no generation of free radicals). This is the first time that photocatalytic or UV absorption properties of any wood-derived biomorphic material or ecoceramic have been reported.
keywords
PHOTOCATALYTIC ACTIVITY; OPTICAL-PROPERTIES; ZINC-OXIDE; ANTIBACTERIAL; PERFORMANCE; REMOVAL; WASTE; ION; NANOSTRUCTURES; NANOPARTICLES
subject category
Engineering
authors
Quarta, A; Novais, RM; Bettini, S; Iafisco, M; Pullar, RC; Piccirillo, C
our authors
Rob Pullar
Collaborator
Rui Miguel Novais
Assistant ProfessorProjects
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2019)
Solar thermochemical production of hydrogen based on cork Ecoceramics (H2CORK)
acknowledgements
This work was financially supported by the projects HApECOrk, funded by Fondazione Con il Sud (project 2015-0243), and FutureInResearch APQ Ricerca Regione Puglia. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, FCT (Fundacao para a Ciencia e a Tecnologia, Portugal) Ref. UID/CTM/50011/2019, financed by national funds through the FCT/MCTES. The authors wish to thank Ms. Stefania D'Amone for the help with SEM microscopy. R.C. Pullar thanks FCT grant IF/00681/2015 for supporting this work, and R.M. Novais wishes to thank FCT project H2CORK (PTDC/CTM-ENE/6762/2014). The authors also acknowledge Amorim Cork Composites for providing the cork samples.