<p>Titanium dioxide (TiO<sub>2</sub>) is extensively implemented in photocatalytic hydrogen (H<sub>2</sub>) production. However, the rapid recombination rate of photogenerated electron–hole pairs in TiO<sub>2</sub> limits the potential to catalyze H<sub>2</sub> photogeneration. In this study, we rationally designed nickel/nickel selenide@nitrogen-doped carbon/TiO<sub>2</sub> (Ni/NiSe<sub>x</sub>@NC/TiO<sub>2</sub>) heterostructures via impregnation assisted by ultrasonication to enhance the photocatalytic activity of TiO<sub>2</sub> in H<sub>2</sub> production. This strategy yields a high interfacial contact between TiO<sub>2</sub> and Ni/NiSe<sub>x</sub>@NC, which reduces the band gap energy and enhances the surface area. This combination yields a type-II heterojunction, as evidenced by X-ray photoelectron spectroscopy analysis of used Ni/NiSe<sub>x</sub>@NC/TiO<sub>2</sub> and OH radical trapping via fluorescence analysis, with high conductive features due to the presence of NC. The presence of Ni metal provides additional sites for H<sub>2</sub> photogeneration. Such features significantly enhance the transfer and separation of electrons, as evidenced by a series of electrochemical analyses. Consequently, the photocatalytic H<sub>2</sub> generation of Ni/NiSe<sub>x</sub>@NC/TiO<sub>2</sub> nanocomposites is enhanced compared with TiO<sub>2</sub>, NiSe/TiO<sub>2</sub>, and Ni/NiSe<sub>x</sub>@NC. Moreover, the highest H<sub>2</sub> production rate is achieved by incorporating 3 wt% Ni/NiSe<sub>x</sub>@NC on TiO<sub>2</sub> with the highest H<sub>2</sub> rate of 5985&#xa0;μmol·g<sup>−1</sup>. Different sacrificial agents show that glycerol exhibits the highest photocatalytic H<sub>2</sub> production rate compared to methanol and glucose. More importantly, Ni/NiSe<sub>x</sub>@NC/TiO<sub>2</sub> shows good stability test until four cycles of photocatalytic reaction. This finding provides an insight into the formation of type-II heterojunction with conductive layers via simple preparation to enhance the photocatalytic H<sub>2</sub> generation.</p> Graphical abstract <p></p>

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Ni/NiSex@N-doped carbon/TiO2 heterostructures for enhanced photocatalytic hydrogen evolution

  • Riki Subagyo,
  • Alice Lim,
  • David Hadid Sidiq,
  • Lei Zhang,
  • Xiongfang Liu,
  • Chi Sin Tang,
  • Xinmao Yin,
  • Caozheng Diao,
  • Hasliza Bahruji,
  • Zjahra Vianita Nugraheni,
  • Yatim Lailun Ni’mah,
  • Didik Prasetyoko,
  • Arramel,
  • Yuly Kusumawati

摘要

Titanium dioxide (TiO2) is extensively implemented in photocatalytic hydrogen (H2) production. However, the rapid recombination rate of photogenerated electron–hole pairs in TiO2 limits the potential to catalyze H2 photogeneration. In this study, we rationally designed nickel/nickel selenide@nitrogen-doped carbon/TiO2 (Ni/NiSex@NC/TiO2) heterostructures via impregnation assisted by ultrasonication to enhance the photocatalytic activity of TiO2 in H2 production. This strategy yields a high interfacial contact between TiO2 and Ni/NiSex@NC, which reduces the band gap energy and enhances the surface area. This combination yields a type-II heterojunction, as evidenced by X-ray photoelectron spectroscopy analysis of used Ni/NiSex@NC/TiO2 and OH radical trapping via fluorescence analysis, with high conductive features due to the presence of NC. The presence of Ni metal provides additional sites for H2 photogeneration. Such features significantly enhance the transfer and separation of electrons, as evidenced by a series of electrochemical analyses. Consequently, the photocatalytic H2 generation of Ni/NiSex@NC/TiO2 nanocomposites is enhanced compared with TiO2, NiSe/TiO2, and Ni/NiSex@NC. Moreover, the highest H2 production rate is achieved by incorporating 3 wt% Ni/NiSex@NC on TiO2 with the highest H2 rate of 5985 μmol·g−1. Different sacrificial agents show that glycerol exhibits the highest photocatalytic H2 production rate compared to methanol and glucose. More importantly, Ni/NiSex@NC/TiO2 shows good stability test until four cycles of photocatalytic reaction. This finding provides an insight into the formation of type-II heterojunction with conductive layers via simple preparation to enhance the photocatalytic H2 generation.

Graphical abstract