Enhanced Electrocatalytic Activity of Copper–Cobalt Nanostructures

Abstract

Novel core–shell nanostructures containing Cu and Co have been synthesized using the microemulsion method at 700 °C. The core consists of Cu–Co composite particles, whereas the shell is composed of Cu–Co alloy particles (shell thickness ∼12 nm). It is to be noted that in bulk Cu–Co binary system there is practically no miscibility. TEM studies show formation of spherical-shaped nanoparticles of core–shell structures. The composition of the core (Cu–Co composite) and shell (Cu–Co alloy) were confirmed by XPS studies. The formation of the Cu–Co alloy as the shell is mainly driven by surface energy considerations. We have also obtained Cu–Co nanocomposites (by controlling the concentration of reducing agent) with particle size in the range of 40–200 nm. These Cu–Co nanostructures show ferromagnetic behavior at 4 K. The saturation magnetization of the core–shell (Cu–Co composite @ Cu–Co alloy) nanostructure (125 emu/g) is found to be higher than that of pure Cu–Co nanocomposite or alloy, which may be useful for applications as a soft magnet. Electrochemical studies of these nanocrystalline Cu–Co particles show higher hydrogen evolution efficiencies (∼5 times) compared to bulk (micrometer-sized) Cu–Co alloy particles.

Bifunctional electro-catalytic performances of CoWO4 nanocubes for water redox reactions (OER/ORR)

“…oxides, [12][13][14] hydroxides, 15 phosphates, [16][17][18] suldes, 19,20 mixed metals 21,22 etc.) were considered as the effective water oxidation electrocatalysts.…”

Cobalt‐Copper Nanoparticles Catalyzed Selective Oxidation Reactions: Efficient Catalysis at Room Temperature

“…The synthesis of the CoCu bimetallic NPs was readily achieved by a facile surfactant free hydrothermal method involving the co‐reduction of Cu 2+ and Co 2+ solutions in strong alkaline medium using hydrazine hydrate, which leads to quantitative yield (Scheme ) . This transformation is typically accompanied by the formation of resulting NPs, the phase structure of which was characterized by powder X‐ray diffraction analyses (see Figure c).…”

Ternary alloy nanocatalysts for hydrogen evolution reaction

“…The current density for A1/GC, A2/GC and A3/GC electrodes was calculated by dividing observed current with geometric area of the electrode and found to be 228, 164 and 152 mA cm −2 with an onset potential range of -0.25 to -0.20 V (vs. RHE) and also followed the same order as [21] or Cu-Co (∼15 mA cm −2 ) in 0.5 M KOH [22] and Ni-Fe (∼120 mA cm −2 ) in 0.5 mol l −1 NaCl [23]. For the reaction…”