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Enhancing the hydrogen generation of TiO2 nanoparticles by decorating its surface with BiI3 and PbI2 quantum dots.

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Title: Enhancing the hydrogen generation of TiO2 nanoparticles by decorating its surface with BiI3 and PbI2 quantum dots.
Authors: Oliva, J.1 (AUTHOR), Gomez-Solis, C.1,2 (AUTHOR) gomez.c@ugto.mx, Pinedo Escobar, J.A.3 (AUTHOR), Vallejo, M.A.2 (AUTHOR), Garcia de la Cruz, D.4 (AUTHOR), Garcia, C.R.5 (AUTHOR), Puentes-Prado, E.6 (AUTHOR)
Source: International Journal of Hydrogen Energy. Feb2021, Vol. 46 Issue 11, p7926-7938. 13p.
Subjects: Interstitial hydrogen generation, Quantum dots, Electron-hole recombination, Platinum nanoparticles, Conduction bands, Conduction electrons, Hydrogen storage, Photoluminescence measurement
Abstract: This work reports the performance of TiO 2 /BiI 3 and TiO 2 /PbI 2 nanocomposites for hydrogen generation. BiI 3 and PbI 2 quantum dots (QDs) were grown on TiO 2 (P25 Degussa) using a fast injection method. According to the analysis by X-ray diffraction, the nanocomposites have a mixture of anatase, rutile and cubic phases from TiO 2 , BiI 3 and PbI 2. The images obtained from transmission electron microscopy revealed that the TiO 2 support have sizes in the range of 70–220 nm while the QDs of BiI 3 and PbI 2 (co-catalysts) grown on TiO 2 have sizes in the range of 12–17 nm. The presence of these iodides on TiO 2 created oxygen vacancies defects (confirmed by photoluminescence measurements) that extended the light absorption of TiO 2 from the UV to the VIS range. According to the results from the photocatalytic experiments for hydrogen generation (achieved using pure water and UV-VIS light), the hydrogen generation rates produced by the TiO 2 /BiI 3 and TiO 2 /PbI 2 nanocomposites were 437–580 times, 81–108 times and 21–30 times, higher than these for pure TiO 2 , PbI 2 and BiI 3 , respectively. The maximum hydrogen generation rates of the TiO 2 /BiI 3 and TiO 2 /PbI 2 nanocomposites were 290.7 and 219.2 μmol h−1 g−1, respectively. In addition, the TiO 2 /BiI 3 and TiO 2 /PbI 2 nanocomposites contained defects that acted as electron trapping centers, which in turn, delayed the electron-hole recombination and this favored the photocatalytic generation of H 2. Moreover, the heterojunction formed between the TiO 2 and the iodides allowed the transfer of electrons from the conduction band of TiO 2 toward the conduction band of the iodides, creating a "sink" for the electrons which delayed the electron hole recombination. The results presented here demonstrated that the deposition of iodide co-catalyst on TiO 2 is a feasible option to enhance the hydrogen generation. Image 1 • TiO 2 /BiI 3 and TiO 2 /PbI 2 nanocomposites were synthesized by a fast injection method. • BiI 3 and PbI 2 QDs enhanced the hydrogen generation of TiO 2 by 437–580 times. • Defects on TiO 2 /BiI 3 and TiO 2 /PbI 2 nanocomposites improved the H 2 production. • The interface TiO 2 /iodides created a sink, delaying the e-h recombination. • The H 2 production was 290.7 and 219.2 μmol h−1 g−1 for TiO 2 /BiI 3 and TiO 2 /PbI 2. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:This work reports the performance of TiO 2 /BiI 3 and TiO 2 /PbI 2 nanocomposites for hydrogen generation. BiI 3 and PbI 2 quantum dots (QDs) were grown on TiO 2 (P25 Degussa) using a fast injection method. According to the analysis by X-ray diffraction, the nanocomposites have a mixture of anatase, rutile and cubic phases from TiO 2 , BiI 3 and PbI 2. The images obtained from transmission electron microscopy revealed that the TiO 2 support have sizes in the range of 70–220 nm while the QDs of BiI 3 and PbI 2 (co-catalysts) grown on TiO 2 have sizes in the range of 12–17 nm. The presence of these iodides on TiO 2 created oxygen vacancies defects (confirmed by photoluminescence measurements) that extended the light absorption of TiO 2 from the UV to the VIS range. According to the results from the photocatalytic experiments for hydrogen generation (achieved using pure water and UV-VIS light), the hydrogen generation rates produced by the TiO 2 /BiI 3 and TiO 2 /PbI 2 nanocomposites were 437–580 times, 81–108 times and 21–30 times, higher than these for pure TiO 2 , PbI 2 and BiI 3 , respectively. The maximum hydrogen generation rates of the TiO 2 /BiI 3 and TiO 2 /PbI 2 nanocomposites were 290.7 and 219.2 μmol h−1 g−1, respectively. In addition, the TiO 2 /BiI 3 and TiO 2 /PbI 2 nanocomposites contained defects that acted as electron trapping centers, which in turn, delayed the electron-hole recombination and this favored the photocatalytic generation of H 2. Moreover, the heterojunction formed between the TiO 2 and the iodides allowed the transfer of electrons from the conduction band of TiO 2 toward the conduction band of the iodides, creating a "sink" for the electrons which delayed the electron hole recombination. The results presented here demonstrated that the deposition of iodide co-catalyst on TiO 2 is a feasible option to enhance the hydrogen generation. Image 1 • TiO 2 /BiI 3 and TiO 2 /PbI 2 nanocomposites were synthesized by a fast injection method. • BiI 3 and PbI 2 QDs enhanced the hydrogen generation of TiO 2 by 437–580 times. • Defects on TiO 2 /BiI 3 and TiO 2 /PbI 2 nanocomposites improved the H 2 production. • The interface TiO 2 /iodides created a sink, delaying the e-h recombination. • The H 2 production was 290.7 and 219.2 μmol h−1 g−1 for TiO 2 /BiI 3 and TiO 2 /PbI 2. [ABSTRACT FROM AUTHOR]
ISSN:03603199
DOI:10.1016/j.ijhydene.2020.12.027