Preparation of GQDs/TiO2 nanotube heterojunction photoanode and its photoelectrochemical performance for water splitting

摘要

Photoelectrochemical (PEC) water splitting is a promising technology for converting solar energy into hydrogen energy. This paper fabricated a GQDs/TiO2 nanotube heterojunctions photoanode by graphene quantum dots (GQDs) assisted anodization method. SEM, TEM, XRD, XPS, FIRT, Raman spectroscopy characterized its morphology and structure. Results demonstrated that graphene quantum dots were incorporated into the TiO2 film layer to form GQDs/TiO2 nanotube array heterojunctions. The introduction of GQDs enhanced the absorption of visible light and significantly improved the charge carrier density from 9.073x10(19) cm(-3) to 1.265x10(21) cm(-3), compared with the TiO2 nanotube array. As a result, the PEC behavior of GQDs/TiO2 nanotube arrays is greatly improved. Under a bias voltage of 0.8 V, the photocurrent density of the GQDs/TiO2 heterojunction photoanode is 5 times higher than that of the pure TiO2 nanotube array. This work provides an important reference for developing high-efficiency PEC water splitting photoanode.

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