Development of binary metal catalysts for production of hydrogen by dehydrogenation of formic acid

The main goal of this thesis is to develop highly efficient heterogeneous catalysts to be used in the dehydrogenation reaction of formic acid. Therefore, four distinct metal oxide supports, including CeO2, Mn5O8, TiO2, and (Polymerization-Induced Colloid Aggregation) PICA-SiO2 were synthesized by utilizing several techniques, including so-gel and multi-stage micro-suspension polymerization methods. The main objective of the synthesis was to improve the properties of these supports and examine their applicability for use in the formic acid dehydrogenation reaction for hydrogen production. In the characterization studies, the properties of the as-synthesized microspheres, such as morphology, particle size, surface area, and crystallinity, were investigated. Furthermore, the catalytic activity of these microspheres was tested by employing them as catalysts in a formic acid dehydrogenation reaction. These microspheres were created by using seed latex made of poly(glycidyl methacrylate) particles. The poly(MAA-co-EDMA) (4-5 μm) was synthesized using the dispersion polymerization technique by first producing a monodisperse poly(GMA) seed latex with a particle size of 2.5 μm, which was then used as a template by providing a surface that contained the special groups to be used during the reaction. Monodisperse-porous poly(MAA-co-EDMA) microspheres were used as a template in a sol-gel templating procedure to create monodisperse-porous CeO2, TiO2, and Mn5O8 microspheres. The synthesis of PICA-SiO2 was carried out using the Polymerization-Induced Colloid Aggregation (PICA) method. Then, in order to produce highly pure and crystalline metal oxide particles, all synthesized microspheres were put through a calcination procedure under particular circumstances to get rid of any organic or inorganic impurities that may have been present during the synthesis process. Following calcination, the metal oxide supports' surfaces underwent surface modification by being exposed to the ligand 3-aminopropyltriethoxysilane (APTES). APTES was used to improve the dispersibility, stability, and biocompatibility of monodisperse-porous metal oxide microspheres, as well as derivatize them. In addition to that, APTES can be used to introduce amine functional groups onto the surface of these metal oxides, in which they can be used to immobilize nanoparticles onto their surface. After that, the noble metal PdAu nanoparticles were immobilized onto their surfaces using a multi-step in-situ precipitation process, producing a catalyst with a uniform distribution of palladium and gold nanoparticles on a support material. The synthesized catalysts were then employed to carry out the dehydrogenation of formic acid to produce hydrogen. Additionally, the four different types of microspheres were compared with one another. Among these catalysts, the PICA-SiO2 support catalyst has shown exceptional results in formic acid decomposition, with 100 % conversion after 6 minutes of reaction, making it an attractive support material. As a result, PdAu@PICA-SiO2 was extensively studied in order to optimize formic acid dehydrogenation to produce hydrogen.