NiSe Nanoparticles Embedded Bimetallic MoCo Nanoflakes as an Effective Bifunctional Electrocatalyst for Water Splitting

Non-noble metals have shown superior catalytic properties compared to noble metal catalysts in green energy generation due to their cost-effectiveness and abundant availability. In our study, we introduced a novel heterostructure comprising bimetallic MoCo nanoflakes as the substrate with anchored NiSe nanoparticles using a hydrothermal method. Various compositions of the MoCo–NiSe heterostructure were synthesized with different weight ratios of bimetallic MoCo and NiSe (2:1, 4:1, and 8:1) to determine the optimal configuration for maximum efficiency. These composite materials were evaluated as bifunctional electrocatalysts in an alkaline medium for the overall water splitting (HER/OER). Remarkably, the amalgamation of bimetallic MoCo with NiSe exhibited enhanced electrochemical water splitting due to increased surface area, porosity, and reduced charge-transfer resistance. The MoCo–NiSe (8:1) electrocatalyst demonstrated a significantly low overpotential of 277 mV (@ j = 10 mA cm^–2) and the lowest Tafel slope of 139 mV dec^–1 for OER. Similarly, MoCo–NiSe (2:1) showed comparable kinetics for HER with lower overpotential (245 mV @ 10 mA cm^–2) and Tafel values (50 mV dec^–1). Furthermore, the electrocatalysts showed excellent stability, as evidenced by chronoamperometry studies conducted for 24 h for both the OER and HER, with an efficiency exceeding 90%. Additionally, the overall water splitting (OWS) initiated at a lower onset potential of 1.66 V @ 10 mA cm^–2, indicating the efficiency and stability achieved during electrocatalysis. The observed properties of the materials can be attributed to the synergistic effects between MoCo nanoflakes and well-dispersed NiSe nanoparticles within the nanoflakes. This study presents a promising approach to creating novel nanomaterials for energy conversion applications.