A step towards efficient water splitting: a high-performance CuCo(OH)2/CNT/MoS2 electrocatalyst

Abstract

A high-performance CuCo(OH)₂/CNT/MoS₂ composite electrocatalyst was synthesized by rapid co-precipitation. This bifunctional material exhibits exceptional electrochemical properties, achieving low overpotentials of 65 mV (OER) and 211 mV (HER) at η₁₀, with Tafel slopes of 96 mV dec⁻¹ and 110 mV dec⁻¹. Notably, CuCo(OH)₂/CNT/MoS₂ demonstrates remarkable durability, sustaining its activity for more than 40 hours in alkaline and 25 hours in acidic media, accompanied by minimal charge transfer resistance. Overall water splitting (OWS) needs a mere 170 mV (1.40 V) of extra energy over the thermodynamic potential, whereas after the stability test (15 hours), the excess potential drops down to 70 mV (1.30 V). The catalytic activity was quantified through turnover frequency (TOF) values of 1.9 × 10⁻³ s⁻¹ (OER) and 3.8 × 10⁻³ s⁻¹ (HER), and mass activities of 20.29 A g⁻¹ (OER) and 21.06 A g⁻¹ (HER). Moreover, CuCo(OH)₂/CNT/MoS₂ achieves a faradaic efficiency of above 80% in the OER process. The synergistic combination of CuCo(OH)₂ (OER active sites) with MoS₂ (edge S as HER active) and CNT enhances electrical conductivity and the surface area, boosting electrochemical performance.