Integrated Quasiplane Heteronanostructures of MoSe 2 /Bi 2 Se 3 Hexagonal Nanosheets: Synergetic Electrocatalytic Water Splitting and Enhanced Supercapacitor Performance

MoSe 2 as a typical transition metal dichalcogenide holds great potential for energy storage and catalysis but its performance is largely limited by its poor conductivity. Bi 2 Se 3 nanosheets, a kind of topological insulators, possess gapless edges on boundary and show metallic character on surface. According to the principle of complementary, a novel integrated quasiplane structure of MoSe 2 /Bi 2 Se 3 hybrids is designed with artistic heteronanostructures via a hot injection in colloidal system. Interestingly, the heteronanostructures are typically constituted by single‐layer Bi 2 Se 3 hexagonal nanoplates evenly enclosed by small ultrathin hierarchical MoSe 2 nanosheets on the whole surfaces. X‐ray photoelectron spectroscopy investigations suggest obvious electron transfer from Bi 2 Se 3 to MoSe 2 , which can help to enhance the conductivity of the hybrid electrode. Especially, schematic energy band diagrams derived from ultraviolet photoelectron spectroscopy studies indicate that Bi 2 Se 3 has higher E F and smaller Φ than MoSe 2 , further confirming the electronic modulation between Bi 2 Se 3 and MoSe 2 , where Bi 2 Se 3 serves as an excellent substrate to provide electrons and acts as channels for high‐rate transition. The MoSe 2 /Bi 2 Se 3 hybrids demonstrating a low onset potential, small Tafel slope, high current density, and long‐term stability suggest excellent hydrogen evolution reaction activity, whereas a high specific capacitance, satisfactory rate capability, and rapid ions diffusion indicate enhanced supercapacitor performance.