Limits...
Anatase TiO2 Nanoparticles with Exposed {001} Facets for Efficient Dye-Sensitized Solar Cells.

Chu L, Qin Z, Yang J, Li X - Sci Rep (2015)

Bottom Line: At the first-step hydrothermal reaction, H-titanate nanowires were obtained in NaOH solution with Ti powder, and at second-step hydrothermal reaction, anatase TiO2 nanoparticles with exposed {001} facets were formed in NH4F solution.If the second-step hydrothermal reaction was carried out in pure water, the H-titanate nanowires were decomposed into random shape anatase-TiO2 nanostructures, as well as few impurity of H2Ti8O17 phase and rutile TiO2 phase.Then, the as-prepared TiO2 nanostructures synthesized in NH4F solution and pure water were applied to the photoanodes of dye-sensitized solar cells (DSSCs), which exhibited power conversion efficiency (PCE) of 7.06% (VOC of 0.756 V, JSC of 14.80 mA/cm(2), FF of 0.631) and 3.47% (VOC of 0.764 V, JSC of 6.86 mA/cm(2), FF of 0.662), respectively.

View Article: PubMed Central - PubMed

Affiliation: School of Science, Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210046, P. R. China.

ABSTRACT
Anatase TiO2 nanoparticles with exposed {001} facets were synthesized from Ti powder via a sequential hydrothermal reaction process. At the first-step hydrothermal reaction, H-titanate nanowires were obtained in NaOH solution with Ti powder, and at second-step hydrothermal reaction, anatase TiO2 nanoparticles with exposed {001} facets were formed in NH4F solution. If the second-step hydrothermal reaction was carried out in pure water, the H-titanate nanowires were decomposed into random shape anatase-TiO2 nanostructures, as well as few impurity of H2Ti8O17 phase and rutile TiO2 phase. Then, the as-prepared TiO2 nanostructures synthesized in NH4F solution and pure water were applied to the photoanodes of dye-sensitized solar cells (DSSCs), which exhibited power conversion efficiency (PCE) of 7.06% (VOC of 0.756 V, JSC of 14.80 mA/cm(2), FF of 0.631) and 3.47% (VOC of 0.764 V, JSC of 6.86 mA/cm(2), FF of 0.662), respectively. The outstanding performance of DSSCs based on anatase TiO2 nanoparticles with exposed {001} facets was attributed to the high activity and large special surface area for excellent capacity of dye adsorption.

No MeSH data available.


Schematic illustration of the synthetic route of TiO2.In pure water, random shape anatase TiO2 with few H2Ti8O17 and rutile TiO2 nanostrutures were formed. While in the present of NH4F, truncated octahedron TiO2 nanoparticles with exposed {001} facets were obtained.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4507182&req=5

f4: Schematic illustration of the synthetic route of TiO2.In pure water, random shape anatase TiO2 with few H2Ti8O17 and rutile TiO2 nanostrutures were formed. While in the present of NH4F, truncated octahedron TiO2 nanoparticles with exposed {001} facets were obtained.

Mentions: Figure 4 illustrates the schematic of the preparation process of random shape TiO2 nanostrctures and truncated octahedron TiO2 nanoparticles with exprosed {001} facets via a two-step hydrothermal reaction process. At the first-step hydrothermal reaction, Ti powder reacted with NaOH to synthesize Na-titanate nanowires. Followed by washing with diluted HCl solution, the Na-titanate nanowires were transformed into H-titanate nanowires via cation exchange reaction. At the second-step hydrothermal reaction, the H-titanate nanowires precursors was under gone completely change in aqueous solution with or without NH4F. In this process, the H-titanate precursors experienced a dissolution and nucleation process during the hydrothermal treatment28. In pure water, the dissolution occurred without any restraint, thus TiO2 nanostructures with random shape distribution were obtained. Moreover, the nucleation was not thorough, and there was few H2Ti8O17 phase and TiO2 rutile phase. When the H-titanate precursors were performed dissolution and nucleation in NH4F solution, single crystal anatase TiO2 nanoparticles with exposed {001} facets were obtained. At the dissolution process, the existing of F− ions could be bonded with Ti atom to reduce the surface energy of the {001} facets to lower than that of the {101} facets, resulting in exposing {001} facets during nucleation2930. Besides, F− ions acted as morphology controlling agent to control the shape of TiO2 nanostructures during nucleation, and the shape of TiO2 nanoparticles was truncated octahedron, as shown in Fig. 4.


Anatase TiO2 Nanoparticles with Exposed {001} Facets for Efficient Dye-Sensitized Solar Cells.

Chu L, Qin Z, Yang J, Li X - Sci Rep (2015)

Schematic illustration of the synthetic route of TiO2.In pure water, random shape anatase TiO2 with few H2Ti8O17 and rutile TiO2 nanostrutures were formed. While in the present of NH4F, truncated octahedron TiO2 nanoparticles with exposed {001} facets were obtained.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507182&req=5

f4: Schematic illustration of the synthetic route of TiO2.In pure water, random shape anatase TiO2 with few H2Ti8O17 and rutile TiO2 nanostrutures were formed. While in the present of NH4F, truncated octahedron TiO2 nanoparticles with exposed {001} facets were obtained.
Mentions: Figure 4 illustrates the schematic of the preparation process of random shape TiO2 nanostrctures and truncated octahedron TiO2 nanoparticles with exprosed {001} facets via a two-step hydrothermal reaction process. At the first-step hydrothermal reaction, Ti powder reacted with NaOH to synthesize Na-titanate nanowires. Followed by washing with diluted HCl solution, the Na-titanate nanowires were transformed into H-titanate nanowires via cation exchange reaction. At the second-step hydrothermal reaction, the H-titanate nanowires precursors was under gone completely change in aqueous solution with or without NH4F. In this process, the H-titanate precursors experienced a dissolution and nucleation process during the hydrothermal treatment28. In pure water, the dissolution occurred without any restraint, thus TiO2 nanostructures with random shape distribution were obtained. Moreover, the nucleation was not thorough, and there was few H2Ti8O17 phase and TiO2 rutile phase. When the H-titanate precursors were performed dissolution and nucleation in NH4F solution, single crystal anatase TiO2 nanoparticles with exposed {001} facets were obtained. At the dissolution process, the existing of F− ions could be bonded with Ti atom to reduce the surface energy of the {001} facets to lower than that of the {101} facets, resulting in exposing {001} facets during nucleation2930. Besides, F− ions acted as morphology controlling agent to control the shape of TiO2 nanostructures during nucleation, and the shape of TiO2 nanoparticles was truncated octahedron, as shown in Fig. 4.

Bottom Line: At the first-step hydrothermal reaction, H-titanate nanowires were obtained in NaOH solution with Ti powder, and at second-step hydrothermal reaction, anatase TiO2 nanoparticles with exposed {001} facets were formed in NH4F solution.If the second-step hydrothermal reaction was carried out in pure water, the H-titanate nanowires were decomposed into random shape anatase-TiO2 nanostructures, as well as few impurity of H2Ti8O17 phase and rutile TiO2 phase.Then, the as-prepared TiO2 nanostructures synthesized in NH4F solution and pure water were applied to the photoanodes of dye-sensitized solar cells (DSSCs), which exhibited power conversion efficiency (PCE) of 7.06% (VOC of 0.756 V, JSC of 14.80 mA/cm(2), FF of 0.631) and 3.47% (VOC of 0.764 V, JSC of 6.86 mA/cm(2), FF of 0.662), respectively.

View Article: PubMed Central - PubMed

Affiliation: School of Science, Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210046, P. R. China.

ABSTRACT
Anatase TiO2 nanoparticles with exposed {001} facets were synthesized from Ti powder via a sequential hydrothermal reaction process. At the first-step hydrothermal reaction, H-titanate nanowires were obtained in NaOH solution with Ti powder, and at second-step hydrothermal reaction, anatase TiO2 nanoparticles with exposed {001} facets were formed in NH4F solution. If the second-step hydrothermal reaction was carried out in pure water, the H-titanate nanowires were decomposed into random shape anatase-TiO2 nanostructures, as well as few impurity of H2Ti8O17 phase and rutile TiO2 phase. Then, the as-prepared TiO2 nanostructures synthesized in NH4F solution and pure water were applied to the photoanodes of dye-sensitized solar cells (DSSCs), which exhibited power conversion efficiency (PCE) of 7.06% (VOC of 0.756 V, JSC of 14.80 mA/cm(2), FF of 0.631) and 3.47% (VOC of 0.764 V, JSC of 6.86 mA/cm(2), FF of 0.662), respectively. The outstanding performance of DSSCs based on anatase TiO2 nanoparticles with exposed {001} facets was attributed to the high activity and large special surface area for excellent capacity of dye adsorption.

No MeSH data available.