Nickel-Cobalt Alloys Electrodeposited at Controlled pH for Hydrogen Production in Al-kalineMedia

M. GÓMEZ; E. A. FRANCESCHINI; G. I. LACCONI

Buenos Aires

Workshop; HYCELTEC 2022; 2022

UBA

NiCo alloy electrodes were synthesized using Ni-Watts baths modified with different proportions of CoSO4·7H2O: 1.5, 3.5 and 15% in mol of Co2+. The synthesis was carried out on AISI 316L steel plates previously coated with Ni strike. The evaluation by electrochemical experiments indi-cates that NiCo electrodes are notably more active for HER than Ni-Watts in alkaline medium. Particularly NiCo 3.5% is the one with the highest current density. In CVs, this elec-trode generates 93.3% more current at -1.5 VSCE than Ni-Watts, and in chronoamperometry it is 889% higher. NiCo 3.5% is observed to have the highest (111)/(200) ratio while maintaining the fcc structure. These planes are associated with the presence of more active sites for hy-drogen detachment in Ni cathode. The presence of nickel and cobalt oxides, formed by exposure to air, was observed in all fresh electrodes. Once aged, the plates developed surface nickel and cobalt hy-droxides which are associated with the formation of pas-sivation layers.