eng Oriental Scientific Publishing Company Material Science Research India 0973-3469 2026-06-20 23 1 08 19 24127 article Chandrama Sarkar 2 Simanta Doley 3 Swapan Kumar Dolui 1 Department of Chemical Sciences, Tezpur University, Napaam, Assam, India Department of Chemistry, Pandit Deendayal Upadhyaya Adarsha Mahavidyalaya, Goalpara, Assam, India Department of Chemistry, Jengraimukh College, Majuli, Assam, India Using a hydrothermal process, we synthesized copper oxide supported on reduced graphene oxide (CuO-rGO) nanocomposites, which we then used as an electro-catalyst for the electro-oxidation of methanol. The CuO-rGO_calcined nanocomposite shown good catalytic activity towards methanol electro-oxidation following calcination at 400 °C. Additionally, FTIR, XRD, Raman spectroscopy, SEM, EDX, and the dynamic light scattering (DLS) method were used to analyse the calcined composites. Cyclic voltammetry (CV) was used to assess the substances electrochemical analyses. The CuO-rGO_calcined nanocomposite experiences irreversible methanol oxidation in an alkaline media. The nanocomposite has a lower positive characteristic peak (0.72 V) in the forward scan compared to CuO (0.75 V). Furthermore, the onset potential of the nanocomposites is lower than that of CuO, suggesting a reduction in the overpotential for methanol oxidation at the nanocomposites. The onset potential for the oxidation of methanol at the CuO-rGO_calcined is around 0.44 V which is lower than that of several reported electrocatalysts such as CuO (ca. 0.46 V), Cu NW@rGO-GCE (ca. 0. 48 V), Cu NW-GCE (ca. 0. 6 V) poly-crystalline Cu-GCE (ca. 0.5 V), and Ni–Cu-GCE (ca. 0.5 V). Additionally, the peak current density at the CuO-rGO_calcined nanocomposite is 2.4 times higher than that of CuO, suggesting the superior electro-catalytic activity of the nanocomposite. Chronoamperometry study reveals the exceptional durability and good tolerance against the oxidizing intermediate of the nanocomposites. The stability of the nanocomposite was further investigated for 100 continuous cycles. CuO-rGO_calcined nanocomposite featuring high durability, low-cost and low onset potential reveals a superior catalytic activity for methanol electro-oxidation. https://www.materialsciencejournal.org/vol23no1/investigating-the-electrochemical-performance-of-cuo-rgo-for-methanol-oxidation-in-alkaline-medium/ Copper oxide Electrocatalyst Nanocomposites Methanol electro-oxidation Reduced graphene oxide