Smart materials for energy applications

In the last decades, electrochemistry has been regarded as a powerful tool to address some of the key challenges that in the framework of sustainability and green energy. In particular, the application of smart, hierarchical materials as electrocatalysts is generating new opportunities for interesting developments. Nanostructured carbon has been heavily employed as a fundamental component for the proposed catalytic materials due to its outstanding electronic and textural properties. This thesis focuses on the exploitation of strategically designed materials based on carbon as electrocatalysts to be used in devices such as new generation fuel cells, electrolyzers for the production of hydrogen peroxide and sensors for its electrochemical detection. Each of these devices is envisioned as a way of reducing the environmental impact, by either being a sustainable source of energy, or substituting energy consuming and non-environmentally friendly processes. In particular, a hybrid Pd/CeO2/C material, prepared through a strategic protocol that allows an intimate contact among the three phases, has been employed as anodic electrocatalyst in both Anion Exchange Membrane Fuel Cells (AEM-FC) and Direct Alcohol Fuel Cells (DAFCs) working in alkaline media and fed with biomass derived polyalcohols. Concerning H2O2 electrosynthesis, N-doped carbon embedding Co nanoparticles have been studied for the Oxygen Reduction Reaction (ORR) in acidic environment, and the material’s outstanding selectivity has been correlated to its N-type species distribution, as well as its porosity and the indirect electronic interaction between the doped carbon phase and the internal metal. Finally, a metal-free electrosensor for the detection of hydrogen peroxide has been produced exploiting the electronic properties of a -COOH decorated graphene, obtained through a controlled functionalization protocol. In all cases, the strategic synthetic procedure gives rise to materials with enhanced catalytic performances in terms of activity, selectivity and stability, and the work has been communicated through publication (already published or in the process of being published) in peer-reviewed journals.