ELECTROCATALYSIS OF THE NEEDLE-LIKE NiMoO4 CRYSTAL TOWARD UREA OXIDATION COUPLED WITH H2 PRODUCTION

In the International Space Station, urine is considered something to be treated. However, urine is mainly composed of water and urea, while they have been demonstrated as an excellent hydrogen carrier for sustainable energy supply. Through the simple chemical coprecipitation and hydrothermal reaction, the needle-like NiMoO 4 crystals were synthesized with the average width around 500 $$ nm and length up to 4 $$ μ $\mu$ m. The resulted products were thoroughly characterized by scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, Fourier-transform infrared spectroscopy and ultraviolet–visible spectrum. The needle-like NiMoO 4 crystals exhibited excellent electrocatalytic oxidation toward urea at anode in alkali solution, leading to the increased performance of hydrogen evolution reaction at cathode with the lower electrochemical potential and energy consumption required to drive the reaction. The high electrocatalysis of the needle-like NiMoO 4 crystals toward urea oxidation reveals their great potential for future application to clean the urine/urea-rich wastewater and to produce hydrogen in space station and environmental wastewater.