Enhanced Photoelectrochemical Water Splitting Using Bismuth/Bismuth Selenide Nanocomposites

Solar-driven photoelectrochemical water splitting is a promising method for generating renewable and sustainable energy, as it effectively harnesses sunlight to convert it into chemical bonds. Among the many materials explored for photoelectrochemical water oxidation, metal selenides stand out because of their narrow band gaps. In this study, we successfully developed a high-performance heterojunction nanostructure comprising a p-type Bi/Bi₂Se₃ photocathode using a facile solvothermal method for efficient water splitting. Various characterization techniques confirmed the structural and optical properties of the fabricated Bi/Bi₂Se₃ nanocomposite. X-ray diffraction (XRD) patterns along with Transmission Electron Microscopy (TEM) images, indicated a single-phase rhombohedral Bi₂Se₃ crystal structure, along with Bi nanoparticles, confirmed the formation of a Bi/Bi₂Se₃ nanocomposite, while X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray (EDX) demonstrated the successful formation of heterojunctions. The as-prepared photocatalyst exhibited an impressive photocurrent density of 395 μAcm⁻² at 0 V versus RHE, which is approximately eight times superior to Bi₂Se₃. Detailed electrochemical characterization revealed that the high photocurrent density of Bi/Bi₂Se₃ is due to improved light harvesting capability, enhanced charge separation, and a suppressed water oxidation back reaction. This innovative approach represents a significant advancement in solar-driven photoelectrochemical water splitting for sustainable energy production.