The rational design of gCN/a-WOx/Pt heterostructured nanophotocatalysts for boosting the hydrogen generation from the hydrolysis of ammonia borane under visible light

Aksoy M., Eken Korkut S., Metin Ö.

International Journal of Hydrogen Energy, vol.48, no.60, pp.22921-22933, 2023 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 48 Issue: 60
  • Publication Date: 2023
  • Doi Number: 10.1016/j.ijhydene.2022.06.186
  • Journal Name: International Journal of Hydrogen Energy
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED)
  • Page Numbers: pp.22921-22933
  • Keywords: Ammonia borane, Amorphous tungsten oxide, Graphitic carbon nitride, Heterojunction, Hydrogen production, Photocatalysts, Platinum nanoparticles
  • Yıldız Technical University Affiliated: Yes


© 2022 Hydrogen Energy Publications LLCIn-situ generation of platinum nanoparticles (Pt NPs) supported on graphitic carbon nitride/amorphous tungsten oxide (gCN/a-WOx) binary heterojunctions under white-light irradiation was performed during the hydrolysis of ammonia borane (HAB). The gCN/a-WOx/Pt(IV) nanocomposites including different amount of W were prepared to study their comparative photocatalysis for the photocatalytic HAB. The yielded gCN/a-WOx/Pt nanocatalysts provided a maximum turnover frequency (TOF) value of 419.2 mol H2 mol Pt−1 min−1, which is higher than that of gCN/Pt nanocatalysts (287.7 mol H2 mol Pt−1 min−1). Many advanced analytical techniques comprising ICP-MS, TEM, HAADF-STEM, XRD, XPS, EDX, and BET were used to determine the elemental composition, morphology, elemental distribution, crystal structure, chemical/oxidation state of the surface elements and the textural properties of the nanocatalysts. The characterization results support the formation of wrinkled paper-like amorphous phase WOx (a-WOx) materials in multiple oxidation states over the gCN nanosheets. The photophysical properties of gCN/a-WOx nanocomposites were also analyzed by using UV–Vis DRS, PL, and TRES techniques to clarify the contribution of the heterojunction formation between gCN and a-WOx semiconductors to the photocatalytic activity. Owing to the enhanced visible light absorption, suppressed charge recombination, and promoted charge carrier transfer, gCN/a-WOx/Pt nanocatalysts boosted the hydrogen production from the HAB under white-light irradiation by providing 419.2 mol H2 mol Pt−1 min−1 TOF, which is 4.8 times higher compared to the one obtained in dark. A plausible photocatalytic mechanism for the photocatalytic HAB reaction in the presence of gCN/a-WOx/Pt nanocatalysts was suggested based on the results of performed scavenger experiments. The rate law and the activation parameters for the of gCN/a-WOx/Pt catalyzed HAB were also reported along with kinetic studies. Additionally, a reusability test was performed to understand the stability of gCN/a-WOx/Pt nanocatalysts in the HAB such that the significance of a-WOx species in the enhancement of photocatalytic activity became more pronounced. This study reports for the first time that gCN/a-WOx heterojunctions are favorable support materials for the in-situ generation of Pt NPs and promoting the photocatalytic activity of Pt NPs in the hydrogen generation from the HAB under white-light illumination.