Improve hydrogen generation by "hybrid water electrolysis"

Abstract

Hydrogen generation by water electrolysis involves a pair of chemical reactions known as hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The nature of OER is usually more sluggish kinetically due to the involvement of 4 electrons whereas HER only requires 2 electrons, indicating higher over-potential requirement at the anode where OER occurs. Due to the difficulties of finding the optimal OER catalyst for oxidative environment, it has been decided to replace OER with UOR (Urea Oxidation Reaction) that consumes lesser energy. Urea oxidation reaction (UOR) is able to decrease the over-potential requirement at the anode in order to improve the efficiency of hydrogen generation at the cathode due to the presence of an organic compound such as urea being readily to be oxidized. The preparation of sulfurized nickel on nickel foam (NiSx/Ni/NF) will be carried out with different parameters to optimize the performances of the electro-catalysts. The optimized NiSx/Ni/NF electro-catalyst will have its data compared with the data recorded from the nickel phosphide on nickel foam (NiPx/Ni/NF) and electro-chemically oxidized nickel on nickel foam (NiOx/Ni/NF) electrocatalysts. The crucial step is to prove that the over-potential at the anode can be decreased by replacing OER with UOR for different nickel-based electro-catalysts. The next move is to discover the optimal nickel-based electro-catalysts to be implemented for highest hydrogen generation efficiency