PdO/TiO2 nanobelt heterostructures with high photocatalytic activities based on an exposed highly active facet on ultrathin TiO2 nanobelts

Abstract

Combining the high photocatalytic activity of P25 (anatase/rutile bi-phase nanoparticle) and the good recycling property of TiO2 nanobelts is a promising approach for the preparation of high performance photocatalysts. In this work, through controlling the volume ratio of the component of organic solvent, bi-phase ultrathin TiO2 nanobelts consisting of both anatase and rutile phases have been successfully synthesized via a one-step solvothermal process by using tetrabutyl titanate as the Ti source and acetic acid/N,N-dimethylformamide (DMF) as the blended organic solvent. Compared with single phase TiO2, the bi-phase TiO2 nanobelts display a superior photocatalytic activity under ultraviolet light irradiation. Based on the refinement result of the X-ray diffraction (XRD) patterns of TiO2 nanobelts, the ratio of anatase and rutile phases in the as-synthesized TiO2 nanobelts were calculated to be 90.8wt% and 9.2wt%, respectively. Scanning electron microscope and high resolution transmission electron microscope images demonstrated that the thickness of the nanobelts is only 3–5nm, and the main exposed facet is (010), a photocatalytically active facet of anatase. The bi-phase and active facet exposure characteristics endow the ultrathin TiO2 nanobelt with high photocatalytic activity, which is superior to P25. The PdO/TiO2 ultrathin nanobelt heterostructures were synthesized at ambient temperature by using ultrathin nanobelts as substrates, which exhibited outstanding photodegradation activity with methyl orange, excellent hydrogen generation, and observably enhanced photoelectrochemical activity under simulated solar irradiation. The efficient suppression of the recombination of photo-induced carriers was caused by the bi-phase characteristics of the ultrathin TiO2 nanobelts. These nanobelts will have great potential in applications for photocatalytic water treatment and hydrogen generation because of the facile synthesis process and superior photocatalytic activity.