Construction of heterostructure based on hierarchical Bi₂MoO₆ and g-C₃N₄ with ease for impressive performance in photoelectrocatalytic water splitting and supercapacitor

Herein, we report the synthesis of a nanohybrid material with hierarchical Bi₂MoO₆ and g-C₃N₄ by a solvothermal method. It shows impressive performance towards photoelectrocatalytic water splitting and supercapacitor applications due to the formation of type-II heterostructures, a higher surface area of 60.7 m²g^-1 (Bi₂MoO₆-44.0 m² g^-1) and higher wettability. The formation of type-II heterostructures reduces the electron-hole recombination and boosts up the interfacial charge transfer in g-C₃N₄/Bi₂MoO₆, and the nanohybrid material (10 wt% g-C₃N₄) shows about 7- and 20-fold higher PEC efficiency than that of Bi₂MoO₆ and g-C₃N₄ under illumination (100 mW cm^-2 (AM 1.5G)). Besides, due to the combination of non-faradaic and faradaic processes, g-C₃N₄/Bi₂MoO₆ (5 wt% g-C₃N₄) exhibits a high specific capacity of 1628 C g^-1 at a current density of 2 A g^-1 in a three-electrode configuration. The symmetric supercapacitor delivers a maximum cell voltage of 1.8 V with a high energy density and a power density of 47 W h kg^-1 and 4500 W kg^-1, respectively, and also shows excellent electrochemical stability with 90% capacitance retention even after 10 000 cycles at a current density of 5 A g^-1.