Modeling Hydrogen Production via Aqueous Phase and Steam Reforming Catalysis

Hydrogen can play a role in the development of renewable energies, which will certainly play a crucial role in the energy transition of the future. Catalytic reforming processes are well-established techniques to obtain hydrogen with high efficiency of conversion. Indeed, steam reforming of biomass or biomass-derived alcohols such as methanol accounts for a great amount of hydrogen production (> 95 %) in refinery and chemical industries. However, a very high temperature under the harsh reaction condition of steam reforming causes catalytic deactivation by coking or catalytic sintering. So, having an optimum yield of hydrogen production at comparatively lower temperatures becomes critical. Experimental observations reveal that introducing an effective promotor into monometallic catalyst may represent one efficient way to stabilize and improve activities of steam reforming metal catalysts. An example of adding an effective promotor is indeed reported in our results described in chapter 3. Within a strict collaboration with experimental colleagues, it has been shown that Cu-In catalysts on silica supports shows an increase of H2 product selectivity when compared with Cu/SiO2 experimentally. The reason for the enhanced catalytic activities of Cu/SiO2 by adding indium were not clear. We applied a powerful technique as the Global Optimization search (GO) to propose finite cluster models of (partially oxidized) monometallic Cu and bimetallic Cu-In catalysts on a model silica support. The GO predictions invariably produced a “necklace†or “belt†of partially oxidized In atoms (InOx phase) at the interface with the silica support in all lowest-energy structures. In is found to act as an electron donor and transfers electrons to the Cu/SiO2 phase, thus modulating the electronic properties of Cu in Cu-In systems. The average CLS predictions are in line with the experimental CLS data, indicating the reliability of our Cu and Cu-In models. We propose that H2O dissociation is a key step to determine the catalytic ...