Exploration of carbon additives to the synthesis of Cu2Mo6S8 structures and their electrocatalytic activity in oxygen reduction reaction

Catalytic processes are contemplated as break point in generating alternative and sustainable energy platforms. The cathodic oxygen reduction reaction (ORR) is an important catalytic system, mainly finding practice in fuel cell and metal-air battery technologies. This work presents the synthesis, structural characterization and electrocatalytic properties of three different Cu₂Mo₆S₈ structures as alternative ORR electrocatalysts. The effect of different carbon additives during synthesis was studied and no positive influence of the carbon addition was indicated. Our findings show that only the bare Cu₂Mo₆S₈ enhances the ORR electro-performance to class with the state-of-the-art ORR catalysts. Excellent stability of 10,000 consecutive ORR cycles, a superior onset potential of 0.894 V and half-wave (E_1/2) potential of 0.641 V vs. reversible hydrogen electrode (RHE) increase the noteworthiness of the Cu₂Mo₆S₈ electrodes. Aside from experimental investigations, density functional theory calculations deliver profound knowledge on the structural and electronic properties (electronic band structure, partial density of states and electron density) of Cu₂Mo₆S₈.