Metallic Metastable Hybrid 1T′/1T Phase Triggered Co,P-SnS₂ Nanosheets for High Efficiency Trifunctional Electrocatalyst

The development of trifunctional electrocatalyst for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) with deeply understanding the mechanism to enhance the electrochemical performance is still a challenging task. In this work, the distorted metastable hybrid-phase induced 1T′/1T Co,P-SnS₂ nanosheets on carbon cloth (1T′/1T Co,P-SnS₂@CC) is prepared and examined. The density functional theoretical (DFT) calculation suggests that the distorted 1T′/1T Co,P-SnS₂ can provide excellent conductivity and strong hydrogen adsorption ability. The electronic structure tuning and enhancement mechanism of electrochemical performance are investigated and discussed. The optimal 1T′/1T Co,P-SnS₂@CC catalyst exhibits low overpotential of ≈94 and 219.7 mV at 10 mA cm⁻² for HER and OER, respectively. Remarkably, the catalyst exhibits exceptional ORR activity with small onset potential value (≈0.94 V) and half-wave potential (≈0.87 V). Most significantly, the 1T′/1T Co,P-SnS₂||Co,P-SnS₂ electrolyzer required small cell voltages of ≈1.53, 1.70, and 1.82 V at 10, 100, and 400 mA cm⁻², respectively, which are better than those of state-of-the-art Pt-C||RuO₂ (≈1.56 and 1.84 V at 10 and 100 mA cm⁻²). The present study suggests a new approach for the preparation of large-scalable, high performance hierarchical 3D next-generation trifunctional electrocatalysts.