microwave assisted synthesis of a nickel-copper composite; promotive effect of melamine on the electrocatalytic activity towards methanol oxidation

Abstract: direct methanol fuel cells (dmfcs) are promising power sources for various applications due to their low operating temperatures, relatively quick start-up, and high power density. methanol oxidation reactions (mor) are the key anodic reactions in dmfcs [1]. they receive significant attention due to various benefits, including their superior specific energy, economical price, and liquid physical state that unambiguously determine the system’s operational safety [2]. platinum-based nanomaterials have been used primarily as anodic electrocatalysts for methanol oxidation. however, the high cost, slow kinetics, and low stability of platinum-based electrocatalysts severely hinder the further commercialization of fuel cells [3]. melamine is a nitrogen source for n doping in the graphene oxide (go) structure. as an electrocatalyst, the ni-cu/n-go hybrid displays excellent catalytic activities for the mor with good stability. the synergic effects of metallic ni and cu, nickel and copper oxides and ni-cu/n-doped go may enhance the performance of the multi-functional hybrid catalyst. in this work, we developed a new pot synthesis strategy for preparing ni-cu / n-go nanocomposites by microwave-assisted process and studied their electrochemical performance. the synthesis method is efficient and fast because microwave heating provides enough heat needed for the reaction in a short time [4]. literature reports show that nickel-based catalysts are good choices for this reaction due to their high conductivity and excellent electrocatalytic activity, and copper due to their high electrochemical stability and high resistance to poisoning [3, 5]. microwave irradiation heating became more attractive for forming catalysts for fuel cells. there are many advantages of using microwave heating instead of traditional heating, such as shorter reaction time, high efficiency, product purity, low cost, reduced hazardous substances, nanostructures with smaller sizes and narrower size distributions which is very important nowadays [2]. the effect of melamine on the electrocatalytic activity of a bimetallic catalyst supported on a graphene oxide is synthesized using a rapid microwave-polyol combined with a thermal treatment as a convenient and controllable technique. the synthesized catalyst is studied by cyclic voltammetry (cv), chronoamperometric (ca), and electrochemical impedance spectroscopy (eis) methods. the promotive effect of melamine is proved by a 203 μa increase in the current and a 0.03 v decrease in onset potential during mor. electrochemical studies for fuel cell applications show that the prepared electrode materials show a good performance, which can be attributed to the excellent dispersion of metal nanoparticles or metal oxides on go and their synergistic interaction with go support.