A research team led by Professor Kangwoo Cho (DESE) and Jiseon Kim (DESE Ph. D. Candidate) has developed a new catalyst to increase the efficiency of hydrogen production reactions using contaminated domestic sewage. This research was recently published in the international academic journal Advanced Functional Materials.
As environmental pollution problems caused by fossil fuels become serious, interest in hydrogen is increasing. Water electrolysis technology, which produces hydrogen by electrolyzing water, is a sustainable process using Earth’s abundant water. However, the rate of oxygen evolution reaction occurring simultaneously with hydrogen production is notably slow, so the energy conversion efficiency is very low.
Researchers have recently solved the problem by combining the urea oxidation reaction with the hydrogen production reaction. Urea, a contaminant contained in urine, releases a significant amount of energy during its oxidation reaction. Thus, it can be utilized to increase the efficiency of hydrogen production and purify toilet wastewater. Ultimately, the catalyst to effectively catalyze the urea oxidation reaction is necessary to increase the efficiency of hydrogen production reaction and wastewater disposal.
To improve the efficiency of the urea oxidation reaction, the research team synthesized a nickel-iron-oxalate (O-NFF) catalyst combining nickel (Ni) metal with iron (Fe) and oxalic acid. The catalyst has a very large surface area combining the nanometer-scale particles in the form of fragments. This property enables it to adsorb more reactants and thus accelerate the urea oxidation reaction.
As a result of the experiment, the research team’s O-NFF catalyst lowered the voltage required for hydrogen evolution to 1.47V RHE (0.5A/cm²) and exhibited a high reaction rate even in a mixed solution of potassium hydroxide (1M) and urea (0.33M). (TeFal = 12.1mV/dec) The research team verified that the catalyst promotes the oxidation reaction of urea through photoelectron/X-ray absorption spectroscopy using a radiation photo accelerator.
“We have developed a catalyst that can improve the efficiency of hydrogen production, an environment-friendly energy source, while purifying domestic wastewater,” said Prof. Cho, who led the research. He added, “We hope that the efficiency of industrial electrolysis hydrogen production would be enhanced with the O-NFF catalyst made of metals and organic matter.”
This research was supported by the Mid-Career Researcher Program and the Future Hydrogen Source Technology Development Program of the National Research Foundation of Korea (NRF), and the National Supercomputing Center.
