S,N-GQD sensitization effect on the improvement of ZnO nanopencil photoelectrochemical properties

Allyn Pramudya Sulaeman*, Rifky Adhia Pratama, Uji Pratomo, None Irkham, Avtar S. Matharu, Indah Primadona*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


ZnO photoanodes in photoelectrochemical (PEC) water splitting for green-hydrogen production are limited due to the large bandgap that is only confined to UV light. One of the strategies for broadening the photo absorption range and improving light harvesting is to modify a one-dimensional (1D) nanostructure to a three-dimensional (3D) ZnO superstructure coupling with a narrow-bandgap material, in this case, a graphene quantum dot photosensitizer. Herein, we studied the effect of sulfur and nitrogen co-doped graphene quantum dot (S,N-GQD) sensitization on the surface of ZnO nanopencil (ZnO NPc) to give a photoanode in the visible light spectrum. In addition, the photo energy harvesting between the 3D-ZnO and 1D-ZnO, as represented by neat ZnO NPc and ZnO nanorods (ZnO NRs), was also compared. Several instruments, including SEM-EDS, FTIR, and XRD revealed the successful loading of S,N-GQDs on the ZnO NPc surfaces through the layer-by-layer assembly technique. The advantages are S,N-GQDs's band gap energy (2.92 eV) decreasing ZnO NPc's band gap value from 3.169 eV to 3.155 eV after being composited with S,N-GQDs and facilitating the generation of electron-hole pairs for PEC activity under visible light irradiation. Furthermore, the electronic properties of ZnO NPc/S,N-GQDs were improved significantly over those of bare ZnO NPc and ZnO NR. The PEC measurements revealed that the ZnO NPc/S,N-GQDs stood out with a maximum current density of 1.82 mA cm−2 at +1.2 V (vs. Ag/AgCl), representing a 153% and 357% improvement over the bare ZnO NPc (1.19 mA cm−2) and the ZnO NR (0.51 mA cm−2), respectively. These results suggest that ZnO NPc/S,N-GQDs could have potential for water splitting applications.

Original languageEnglish
Pages (from-to)18396-18403
Number of pages8
JournalRSC Advances
Issue number27
Publication statusPublished - 19 Jun 2023

Bibliographical note

Funding Information:
This work was supported by the grant from Internal Research Grant through Riset Percepatan Lektor Kepala Universitas Padjadjaran under contract number 2203/UN6.3.1/PT.00/2022. The authors acknowledge the facilities, scientific and technical support from Advanced Characterization Laboratories Bandung, National Research and Innovation Agency E-Layanan Sains.

Publisher Copyright:
© 2023 The Royal Society of Chemistry.

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