Exploiting synergistic effects of CoTe nanostructures and mesoporous graphene for enhanced OER electrocatalysis

The development of efficient, sustainable, and cost-effective electrocatalysts for the oxygen evolution reaction (OER) is critical to advancing renewable energy technologies such as water splitting and metal–air batteries. In this study, we present a nanohybrid catalyst composed of cobalt monotelluride (CoTe) uniformly distributed within the surface and mesoporous framework of graphene (MG). The synergistic integration of CoTe and MG enhances electrical conductivity, increases surface area, and promotes the exposure of active catalytic sites, thereby improving OER kinetics. The CoTe/MG hybrid was synthesized via a facile hydrothermal co-reduction method, enabling precise control over CoTe loading (5–30 wt%). Among the compositions studied, the catalyst holding 20 wt% CoTe shows outstanding OER activity, achieving a low overpotential of 230 mV at 10 mA cm⁻² in 1.0 M KOH, a small Tafel slope of 48 mV dec⁻¹, and excellent stability in alkaline conditions. Comprehensive analysis reveals that the self-reconstructed surface favors the OER, resulting in an improved performance. These results highlight the potential of CoTe/MG nanohybrids as robust and high-performance electrocatalysts for sustainable energy conversion applications.