Graphene dot-embedded porous WO₃ photoanode for highly efficient photoelectrochemical water splitting

The development of semiconductor photoanodes with improved photoelectrochemical (PEC) efficiency and stability for the purpose of realizing solar water splitting is a crucial challenge that carries substantial practical implications.

In this study, GQDs/WO₃ composite porous photoanodes were fabricated using a pulsed anodization method in an aqueous electrolyte containing hydroxyl GQDs. The morphology and crystal structure of the as-prepared GQDs/WO₃ porous films were characterized by SEM, TEM, XRD, XPS, Raman spectra, and FTIR. The successful embedding of GQDs into the WO₃ walls to form tightly bound heterojunctions was confirmed. It was investigated how the GQD content influenced the photoelectrochemical properties of the GQDs/WO₃ heterojunctions. The optimal photocurrent densities observed in the GQDs/WO₃ samples (10-WO₃) were found to be three times higher compared to those obtained from pure WO₃ porous films. This significant enhancement clearly indicates the positive impact of GQDs on the PEC performance. The boosted PEC activity of the GQDs/WO₃ heterojunction photoanode was attributed to the fact that the introduction of GQDs promotes more efficient light absorption, charge separation, and transport processes within the heterojunction structure. Moreover, the GQDs/WO₃ composites photoelectrodes exhibited excellent PEC stability, predicting its enormous potential for practical applications.