Adsorption and catalysis in hydrogen evolution reaction environments

Abstract

Renewable energy generation methods, such as solar or wind power, are cost-effective and environmentally friendly energy sources, but their intermittent nature creates considerable challenges in their incorporation into the current energy infrastructure. As it stands, some of the production capacity has to be disconnected when supply exceeds demand, thus lowering the proftability of investments into renewable energy.

One potential solution is using the excess energy to produce hydrogen. Water molecules are dissociated into hydrogen and oxygen gases in electrolyzers and catalysts are used to improve the effciency of these gas evolution reactions. However, the best catalyst materials are composed of valuable metals, such as platinum or palladium, resulting in increased investment costs of hydrogen production.

In order to reduce the quantity of the required noble metals, the frst article of this doctoral dissertation examined the production of silver and palladium nanoparticles by electrodeposition in electrolytes based on different aqueous isotopes. The nucleation mechanism of the electrodeposition process was determined to be progressive in nature and that the growth of the nanoparticles could be suppressed with the use of D2O-based solvents. The origin of damage observed in CR-39 polymer pieces in hydrogen evolution reaction environments was the focal point of the second research article of the thesis. Cavitation collapse of nanobubbles formed during gas evolution reactions was judged to be the most probable explanation for the origin of the damage. The third research article surveyed the adsorption sites of hydrogen atoms on the Pt(111) catalyst surface using electron paramagnetic resonance spectroscopy. It was reasoned that hydrogen adsorbs primarily onto on-top and fcc hollow sites.

Results from this research offer potential tools for the development of more specialized and cost-effective catalyst materials, and aid in characterizing material deterioration in hydrogen evolution reaction environments.