Electrodeposition and Characterization of Nanocrystalline Ni‐Mo Catalysts for Hydrogen Production

Abstract

Ni-Mo nanocrystalline deposits (7–43 nm) with a nodular morphology were prepared by electrodeposition using direct current from citrate-ammonia solutions. They exhibited a single Ni-Mo solid solution phase. The size of the nodules increased as electroplating current density increased. The molybdenum content—estimated using EDX analysis—in the deposits decreased from about 31 to 11 wt% as the current density increased from 5 to 80 mA·cm−2. The highest microhardness value (285 Hv) corresponded to nanodeposits with 23% Mo. The highest corrosion resistance accompanied by relatively high hardness was detected for electrodeposits containing 15% Mo. Mo content values between 11 and 15% are recommended for obtaining better electrocatalytic activity for HER.

Electrodeposition and Properties of Nanocrystalline Ni-Based Alloys with Refractory Metal from Citrate Baths / Elektroosadzanie I Własciwosci Nanokrystalicznych Stopów Na Osnowie Niklu Z Trudnotopliwym Metalem Z Kapieli Cytrynianowych

“…6). These results are in close agreement with data reported in numerous papers [7][8]26]. Moreover, an increase in the rate of mass transport causes reduction of the current efficiency related to the higher content of (diffusion controlled) molybdenum in alloys [19].…”

“…These effects have resulted in a decrease of the relative content of molybdenum in the alloy with an increase of current density (or cathode potential decrease). Also, during co-deposition process a significant increase of the hydrogen evolution is observed due to the low hydrogen overvoltage on the molybdenum oxides or on molybdenum alloys [25][26]. Furthermore, on the basis of SEM, XRD and XPS analysis of resulting deposits, it was found that metallic, nanocrystalline and homogenous coatings are obtained when the potential is shifted to more negative values than -1.35V/SCE.…”

Surface morphology and electrochemical characterization of electrodeposited Ni–Mo nanocomposites as cathodes for hydrogen evolution

“…Electrodeposited Ni-Mo composites showed higher corrosion rates (0.035-1.795 mm/y) compared to the corrosion rates of Ni-Mo electrodeposited alloys (4.7-8.3 × 10 −3 mm/y) [16]. This result would be attributed to the non homogeneity and the rough surface of the Ni-Mo composites compared to the surface of Ni-Mo alloys.…”

“…surface. The morphology of the composite films shows rougher, more irregular and more developed morphology than that of the alloy films [16].…”

Morphology and Electrochemical Characterization of Electrodeposited Nanocrystalline Ni-Co Electrodes for Methanol Fuel Cells

“…Electrodeposition has a lot of advantages over other surface modification techniques such as low cost and capability of manufacturing multicomponent nanocrystalline materials for many energy applications [25][26][27][28].…”