Two-Dimensional Materials for Environmental Remediation and Energy Storage

Nanostructured materials play an important role in applications in environmental remediation and energy storage. This PhD project initially focused on the elimination of chloridazon, a herbicide extensively used in sugar beet cultivation, from water. The potential of pillared smectite clay and of graphene oxide as adsorption material for this pollutant and its metabolites was demonstrated. Three-dimensional heterostructures, built by stacking nanometer thick layers of these materials with well-chosen pillars in between them, allow not only to create pores with a specific size and chemical affinity for trapping a specific molecule, but can also serve as scaffold for growing nanoparticles of a certain size. This was exploited in producing a new hydrogen storage material that could serve to replace fossil fuels by hydrogen in cars. By synthesizing nanometer-sized magnesium hydride nanoparticles in a lightweight scaffold of pillared reduced graphene oxide, two important shortcomings of Mg as hydrogen storage medium for automotive applications were overcome: its sluggish kinetics for hydrogen absorption/desorption and its high hydrogen desorption temperature. Another project, also in the field of energy storage, aimed at developing more effective and stable lithium-sulfur batteries for potable electronic devices. A novel cathode material based on MXene, consisting of a-few-atoms-thick layers of transition metal carbonitride, was synthesized and coated with polyacrylamide formed in the presence of Li2S8. This new cathode was shown to speed up the redox kinetics and prevent diffusion of lithium polysulfides, which deteriorate battery performance, into the electrolyte, thereby overcoming two major problems with this type of batteries