We demonstrate that hydrogen treatment is a simple and effective strategy to fundamentally improve the performance of TiO2 nanowires for photoelectrochemical (PEC) water splitting. Hydrogen-treated rutile TiO2 (H:TiO2) show substantially enhanced photocurrent compared to pristine TiO2, and a exceptionally low photocurrent saturation potentials of 0.4 V vs. RHE. The optimized H:TiO2 nanowire sample yields a photocurrent density of 1.97 mA/cm2 at 0.4 V vs. RHE, in 1 M NaOH solution under the illumination of simulated solar light. IPCE analyses confirm the photocurrent enhancement is mainly due to the improved photoactivity of TiO2 in the UV region. The solar-to-hydrogen efficiency is calculated to be ~1.1%. Hydrogen treatment increases the donor density of TiO2 nanowires by 3 orders of magnitudes, via creating a high density of oxygen vacancies that serve as electron donors. The capability of making highly photoactive H:TiO2 nanowires opens up new opportunities in PEC water splitting and photocatalysis.

Hydrogen-treated TiO2 nanowire arrays for photoelectrochemical water splitting

243rd National Meeting (2012)

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