Development of transition metal-based catalytic systems for water-splitting reactions

Thesis

Hydrogen is a promising energy carrier as its combustion produces only water and no greenhouse gases. While hydrogen is the most abundant chemical element in the universe, on Earth it is very scarce as a gas. Industrial production of hydrogen still relies on non-renewable fossil fuels. Water-splitting using renewable energy is the most sustainable alternative. However, the process involves the use of precious metal catalysts - platinum for the hydrogen evolution reaction (HER) and iridium or ruthenium for the oxygen evolution reaction (OER).

The work presented in this Thesis focuses on improving water-splitting reactions with the use of non-noble transition metal-based catalysts via three different methods. First, the fundamental chemistries involved with the use of an external magnetic field in electrocatalysis are explored. External stimuli, such as heat and pressure, are commonly used to enhance catalytic reactions. This Thesis employs an active catalyst (Co3O4) and a highly magnetic co-catalyst (BaFe12O19) and investigates the use of a magnetic field for enhancement of the electrocatalytic oxygen evolution reaction. Second, the use of rare-earth elements - commonly referred to as the lanthanide series - as modifiers for Ni2P nanocatalysts is explored. Despite their misleading name, which refers more to the challenges associated with their extraction and separation, rare-earth elements are very abundant. Therefore, their use in electrocatalysts present an exciting avenue of research for the replacement of precious metals. Finally, these pristine and lanthanide-modified Ni2P-based catalysts are explored as photocatalysts in dye-sensitised hydrogen production.

The research presented here is an important step forward in furthering our understanding of magneto-electrocatalysis and designing transition metal-based catalytic systems for the clean production of hydrogen fuel.

Authors: Szalay, D

• DOI: 10.5287/ora-2aejpdn9b
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: electrocatalysis; nanoparticles; oxygen evolution reaction; heterogeneous catalyst; magnetism
• Subjects: Chemistry, Inorganic; Materials science