CoTe2–NiTe2 heterojunction directly grown on CoNi alloy foam for efficient oxygen evolution reaction

Abstract

The development of high-efficiency and durable non-noble metal-based oxygen evolution reaction (OER) electrocatalysts is a particularly urgent need for electrochemical water splitting. An effective electrocatalyst can be prepared by tailoring the composition, morphology, and structure of the material. Herein, we report a CoTe₂–NiTe₂ heterojunction directly grown on CoNi alloy foam (CNF) via a simple hydrothermal route. The optimized electrode of 3CNT/CNF-240C was achieved through the adjustment of reductant addition of N₂H₄·H₂O and the reaction temperature in the hydrothermal reaction. The 3CNT/CNF-240C electrode only needs a low overpotential of 280 mV to attain an anodic current density of 10 mA cm⁻², and shows fast kinetics for the OER with a small Tafel slop of 19.4 mV dec⁻¹. The enhanced OER performance could be attributed to the interaction between CoTe₂ and NiTe₂ in the heterojunctions promoting the charge transfer process. Moreover, 3CNT/CNF-240C also shows excellent long-term stability, which can maintain 18 h of continuous electrolysis without obvious degradation. Our research provides a new strategy for the direct synthesis of integrated hybrid structured electrocatalysts to achieve highly active and durable water splitting.