| Abstract [eng] |
The extensive research on the intrinsic (composition, structure) and extrinsic (electrochemical properties) interdependencies of alloys of the iron group metals (Me = Co, Ni, Fe) with the high content W/Mo have been carried out in order to elucidate the opportunities for the design/application of these alloys as multifuncional electro-catalysts for energy conversion. The well-thought conditions of electrodeposition of alloys allowed to obtain homogeneous, compact, well adhered to the substrate coatings having up to ~ 30 at.% of W and ~ 50 at.% of Mo, that are characterized by ultra-nanocrystalline structure (the crystallite size < 5 nm), having two phases: W/Mo solid solution in Me and corresponding intermetallic compound. The catalytic activity for the alkaline hydrogen evolution reaction reduces in the following order (in at.%): Co–52Mo > Ni–54Mo > Fe–54Mo > Ni-29W > Co-33W > Fe-30W. Another way to increase the activity was shown through the template deposition of Co-W nanowires (NWs): apparent exchange current density increased by 200 times for Co-W alloy NWs compared to their coatings. The formation of the Co3W intermetallic phase provides superior corrosion resistance to Co-W coatings, that was successfully used for catalytic anodic oxidation of methanol in H2SO4. The anodic peak current density of methanol oxidation was 12.3 mA·cm−2 which is higher than on Pt (2.4 mA cm-2). The modification of the binary alloys by introducing the third element (P, Cu, Au) allowed to improve their applicability. Another opportunity was gathered by fabrication of a novel nano-composite NWs arrays, where Co-W matrix was modified with Au nanoparticles in order to design new material for sensing application. |
