Some Distinct Attributes of ZnO Nanorods Arrays: Effects of Varying Hydrothermal Growth Time

Mohammed Rashid Almamari; Naser M Ahmed; Araa Mebdir Holi; F K Yam; Htet Htet Kyaw; M A Almessiere; Mohammed Z Al-Abri

doi:10.3390/ma15175827

Some Distinct Attributes of ZnO Nanorods Arrays: Effects of Varying Hydrothermal Growth Time

Materials (Basel). 2022 Aug 24;15(17):5827. doi: 10.3390/ma15175827.

Authors

Mohammed Rashid Almamari^{1

2}, Naser M Ahmed^{2

3}, Araa Mebdir Holi⁴, F K Yam², Htet Htet Kyaw¹, M A Almessiere^{5

6}, Mohammed Z Al-Abri^{1

7}

Affiliations

¹ Nanotechnology Research Center, Sultan Qaboos University, P.O. Box 17, Al Khoud, Muscat 123, Oman.
² School of Physics, Universiti Sains Malaysia, Penang 11800, Malaysia.
³ Research Center, The University of Mashreq, Baghdad 10021, Iraq.
⁴ Department of Physics, College of Education, University of Al-Qadisiyah, Al-Diwaniyah 58002, Al-Qadisiyah, Iraq.
⁵ Department of Physics, College of Science, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia.
⁶ Department of Biophysics, Institute for Research & Medical Consultatuins (IRMC), Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia.
⁷ Department of Petroleum and Chemical Engineering, College of Engineering, Sultan Qaboos University, P.O. Box 33, Al Khould, Muscat 123, Oman.

Abstract

This study investigates the growth time effect on the structural, morphological, optical, and photoelectrochemical characteristics of highly oriented ZnO nanorod arrays (ZNRAs). The nanorod arrays were grown on ITO substrates using the unified sol-gel spin coating and hydrothermal techniques. ZnO nanoparticles (ZNPs) were synthesized using the sol-gel spin coating method. In contrast, the hydrothermal method was used to grow the ZnO nanorods. The hydrothermal growth time investigated was between 4 and 12 h. The synthesized ZNRAs were used as the photoanode electrodes to investigate their photoelectrochemical (PEC) electrode potency. The as-prepared ZNRAs were characterized using various analytical tools to determine their structures, morphologies, optical, and photoelectrochemical traits. EDX spectra showed the presence of uncontaminated ZnO chemical composition, and FTIR spectra displayed the various functional groups in the samples. A rod-shaped ZnO nanocrystallite with mean lengths and diameters of 300-500 nm and 40-90 nm, respectively, is depicted. HRTEM images indicated the nucleation and growth of ZNRAs with a lattice fringe spacing of 0.26 nm and a growth lattice planer orientation of [002]. The optimum ZNRAs (grown at 8 h) as photoelectrode achieved a photoconversion efficiency of 0.46% and photocurrent density of 0.63 mA/cm², that was 17 times higher than the one shown by ZNPs with Ag/AgCl as the reference electrode. Both values were higher than those reported in the literature, indicating the prospect of these ZNRAs for photoelectrode applications.

Keywords: PEC; ZNRAs; hydrothermal growth time; photoconversion efficiency; photoelectrode.

Grants and funding

This research was funded by [Universiti Sains Malaysia] grant number [304/PFIZIK/6315514]. And The APC was funded by [Nanotechnology Research Center, Sultan Qaboos University, Oman].