Solar driven organic transformations to enhance hydrogen production

Abstract

Our proposal is to find the most efficient and stable photocatalysts and co-catalysts for selective glycerol oxidation to DHA using a photoelectrochemical cell (PCE) system. Understanding of the oxidation reaction, its mechanism and kinetics are also the focus of this proposal using techniques, which are complementary from both Institutions. Glycerol is a sub-production from the biodiesel industry and Brazil is the second-largest producer and consumer of biodiesel, behind only the United States (USA). Brazilian biodiesel production is estimated to rise from 5.4 to over 10 billion liters annually, between 2018 and 2023. Thus, a green, sustainable and efficient way to convert the sub-product glycerol in a more added-value product is desired and needed. Using a PEC system, the electrons generated in the light-driven oxidation of glycerol can also be used to generate hydrogen. For this project we propose a detailed investigation of the following photocatalysts SrTiO3, ±-Fe2O3 and BiVO4 modified with 2D materials (graphene and MoS2) and NiOx and NiFeOOH as co-catalysts. The goals are focused on employing photocatalysts that can be prepared by simple routes and that are cheap and abundant. Both groups have expertise in the synthesis of the materials and their composites proposed herein. Besides, the project also wants to avoid the use of expensive metallic catalysts and alloys, envisaging the possibility to produce large-area PEC systems. For their characterization, complementary and powerful characterization techniques available at both Institutions will be employed: in-situ infrared and mass spectroscopy coupled to a (photo)electrochemical cell; in-situ XAS absorption spectroscopy and high-resolution X-ray diffraction at CNPEM-Sirius; transient absorption spectroscopy (TAS); Raman-AFM spectroscopy; in-situ transient (time-correlated single-photon counting); and for in-situ energetics (air photoelectron spectroscopy & surface photovoltage spectroscopy); operands light-induced spectroelectrochemistry; nuclear magnetic resonance (H-NMR and C-NMR) and HPLC for products analysis. (AU)