The pfoto is sourced from rscf.ru
Water electrolysis required electrocatalysts to facilitate the H2O decomposition into hydrogen and oxygen when exposed to electric current. The metals from the ferrum sub-group (nickel, ferrum, cobalt) serve as the basis for such electrocatalysts, as well as their composite materials with noble metals – copper or silver. Nickel-copper is one of the most common composite materials, however, due to oversized metal particles their use is not very efficient.
Scientists from the Institute of Physics and Engineering named after A.F. Ioffe with the Russian Academy of Sciences (Saint-Petersburg) attempted to resolve this problem by developing new electrocatalysts and covering the carbon microtubes with composite materials based on Nickel (Ni) and copper (Cu). For this purpose, the scientists used complex ammonia-sulfosalicylic electrolytes (substances conducting electric current due to dissociation into ions) with more complex structure compared to standard electrolytes.
This method allowed for creating super-thin coating with metals nanoparticles: the depth of the tubes with nickel coating is 1.2 nanometres, with nickel-copper coating – only 0.5 nanometres. The received samples were studied using the scanning electron microscopy, as well as X-ray and electrochemical methods. The experiments showed that the authors succeeded in increasing the electrochemically active surface of materials: for nickel-based catalyst it grew from 265 up to 1,400 cm2, and for nickel-copper-based – from 265 up to 780. This improved the efficiency of Hydrogen recovery during the water electrolysis.
“We achieved the improvement of electrocatalytic properties both by decreasing the size of the crystal grains, and by adding copper. Copper improves the electric conductivity and decreases the total energy of the metal-hydrogen connection weakening the diffusion limitations of the reaction. The synthesised material may be used for efficient synthesis of hydrogen and oxygen in various spheres: from making green fuel or recovering pure metals from ore to receiving pure oxygen in medical and engineering spheres”, the Russian Scientific Fund cites the words of Dmitry Dmitriyev, the researcher in the Institute of Physics and Engineering named after A.F. Ioffe with the Russian Academy of Sciences.