Bimetallic Ni-Co ditelluride/mesoporous graphene nanohybrids for improved electrocatalytic oxygen evolution reaction

Abstract

Developing highly efficient, sustainable, and economically viable oxygen evolution reaction (OER) catalysts is essential for the progress of electrocatalytic systems in energy conversion technologies. In this study, the Ni:Co ratio in Ni<inf>x</inf>Co<inf>1-x</inf>Te<inf>2</inf> nanostructures was initially optimized to enhance OER activity, with the 1:1 Ni:Co composition demonstrating superior performance due to favorable electronic interactions and increased exposure of active sites. To further improve catalytic efficiency, NiCoTe<inf>2</inf> was integrated into mesoporous graphene (MG) by a hydrothermal synthesis route, forming a novel hybrid nanocatalyst. The resulting NiCoTe<inf>2</inf>/MG nanohybrid with the large, exposed area and excellent conductivity of MG, leading to enhanced active site accessibility and improved electrocatalytic performance. Synthesized through a simplistic hydrothermal co-reduction method, the nanohybrid was prepared with NiCoTe<inf>2</inf> loadings of 5, 10, and 20 wt%, among which the 10 wt% loading exhibited the best OER activity. This optimal composition achieved a small overpotential of 270 mV at 10 mA cm−2 in 1.0 M KOH, a Tafel slope of 106 mV dec−1, and long-term durability for 30 h under alkaline conditions. These findings demonstrate the improved electrocatalytic performance and durability of the NiCoTe<inf>2</inf>/MG nanohybrid, positioning it as a potential candidate for sustainable energy applications. © 2025 Elsevier B.V., All rights reserved.