Controlled synthesis of Pt-loaded yolk–shell TiO₂@SiO₂ nanoreactors as effective photocatalysts for hydrogen generation

Abstract

Yolk–shell and hollow structures are powerful platforms for controlled release, confined nanocatalysis, and optical and electronic applications. This contribution describes a fabrication strategy for a yolk–shell nanoreactor (NR) using a post decoration approach. The widely studied yolk–shell structure of silica-coated TiO₂ (TiO₂@SiO₂) was used as a model. At first, anatase TiO₂ spheres were prepared, and subsequently were given a continuous coating of carbonaceous and silica layers. Finally, the carbonaceous layer was removed to produce a yolk–shell structure TiO₂@SiO₂. By using an in-situ photodeposition method, Pt-encased spheres (Pt-TiO₂@SiO₂) were synthesized with Pt nanoparticles grown on the surface of the TiO₂ core, which contained void spaces suitable for use as NRs. The NR showed enhanced hydrogen production with a rate of 24.56 mmol·g⁻¹·h⁻¹ in the presence of a sacrificial agent under simulated sunlight. This strategy holds the potential to be extended for the synthesis of other yolk–shell photocatalytic NRs with different metal oxides.

Graphical abstract

Keywords

nanoreactor / TiO₂ / SiO₂ / photocatalyst / hydrogen generation

References

[1] Teng Z, Li W, Tang Y, . Mesoporous organosilica hollow nanoparticles: synthesis and applications. Advanced Materials, 2019, 31(38): 1707612

[2] Zhu W, Chen Z, Pan Y, . Functionalization of hollow nanomaterials for catalytic applications: nanoreactor construction. Advanced Materials, 2019, 31(38): 1800426

[3] Ji L, Zheng H, Wei Y, . Temperature-controlled fabrication of Co–Fe-based nanoframes for efficient oxygen evolution. Science China Materials, 2022, 65(2): 431–441

[4] Lee J, Kim S M, Lee I S. Functionalization of hollow nanoparticles for nanoreactor applications. Nano Today, 2014, 9(5): 631–667

[5] Zuo B, Li W, Wu X, . Recent advances in the synthesis, surface modifications and applications of core–shell magnetic mesoporous silica nanospheres. Chemistry: An Asian Journal, 2020, 15(8): 1248–1265

[6] Gao C, Lyu F, Yin Y. Encapsulated metal nanoparticles for catalysis. Chemical Reviews, 2021, 121(2): 834–881

[7] Xiong S, Tang R, Gong D, . Yolk–shell catalyst: from past to future. Applied Materials Today, 2020, 21: 100798

[8] Vaz B, Salgueirino V, Perez-Lorenzo M, . Enhancing the exploitation of functional nanomaterials through spatial confinement: the case of inorganic submicrometer capsules. Langmuir, 2015, 31(32): 8745–8755

[9] Sanles-Sobrido M, Perez-Lorenzo M, Rodriguez-Gonzalez B, . Highly active nanoreactors: nanomaterial encapsulation based on confined catalysis. Angewandte Chemie International Edition, 2012, 51(16): 3877–3882

[10] Yeo K M, Choi S, Anisur R M, . Surfactant-free platinum-on-gold nanodendrites with enhanced catalytic performance for oxygen reduction. Angewandte Chemie International Edition, 2011, 50(3): 745–748

[11] Xiao M, Zhao C, Chen H, . “Ship-in-a-bottle” growth of noble metal nanostructures. Advanced Functional Materials, 2012, 22(21): 4526–4532

[12] Chen J, Bai Y, Feng J, . Anisotropic seeded growth of Ag nanoplates confined in shape-deformable spaces. Angewandte Chemie International Edition, 2021, 60(8): 4117–4124

[13] Kwon T, Kumari N, Kumar A, . Au/Pt-egg-in-nest nanomotor for glucose-powered catalytic motion and enhanced molecular transport to living cells. Angewandte Chemie International Edition, 2021, 60(32): 17579–17586

[14] Tanaka S, Nogami D, Tsuda N, . Synthesis of highly-monodisperse spherical titania particles with diameters in the submicron range. Journal of Colloid and Interface Science, 2009, 334(2): 188–194

[15] Wang S, Wang T, Chen W, . Phase-selectivity photocatalysis: a new approach in organic pollutants’ photodecomposition by nanovoid core (TiO₂)/shell (SiO₂) nanoparticles. Chemical Communications, 2008, (32): 3756–3758

[16] Wang T, Wang S, Chen W, . Chemical morphology freezing: chemical protection of the physical morphology of high photoactivity anatase TiO₂ nanotubes. Journal of Materials Chemistry, 2009, 19(27): 4692–4694

[17] Wang S, Wang T, Gao Y, . Wet photochemical filling: a new low-diameter tube-filling method based on differentiated nanotube surfaces. Journal of Materials Chemistry, 2011, 21(48): 19337–19343

[18] Mulvaney P. Surface plasmon spectroscopy of nanosized metal particles. Langmuir, 1996, 12(3): 788–800

[19] Wood A, Giersig M, Mulvaney P. Fermi level equilibration in quantum dot-metal nanojunctions. The Journal of Physical Chemistry B, 2001, 105(37): 8810–8815

[20] López R, Gómez R. Band-gap energy estimation from diffuse reflectance measurements on sol–gel and commercial TiO₂: a comparative study. Journal of Sol-Gel Science and Technology, 2012, 61(1): 1–7

[21] Munir S, Shah S M, Hussain H, . Effect of carrier concentration on the optical band gap of TiO₂ nanoparticles. Materials & Design, 2016, 92: 64–72

[22] Can E, Uralcan B, Yildirim R. Enhancing charge transfer in photocatalytic hydrogen production over dye-sensitized Pt/TiO₂ by ionic liquid coating. ACS Applied Energy Materials, 2021, 4(10): 10931–10939

[23] Wang F, Jin Z, Jiang Y, . Probing the charge separation process on In₂S₃/Pt-TiO₂ nanocomposites for boosted visible-light photocatalytic hydrogen production. Applied Catalysis B: Environmental, 2016, 198: 25–31

[24] Cao B, Li G, Li H. Hollow spherical RuO₂@TiO₂@Pt bifunctional photocatalyst for coupled H₂ production and pollutant degradation. Applied Catalysis B: Environmental, 2016, 194: 42–49

[25] Zhang J, Yu Z, Gao Z, . Porous TiO₂ nanotubes with spatially separated platinum and CoO_x cocatalysts produced by atomic layer deposition for photocatalytic hydrogen production. Angewandte Chemie International Edition, 2017, 56(3): 816–820

Disclosure of potential conflicts of interest

The authors declare that they have no conflict of interest.

Acknowledgements

We thank the Natural Science Foundation of Zhejiang Province (Grant No. LZ22C100002) and the 521 Talent Project of Zhejiang Sci-Tech University for providing financial support.

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