Capacitive performance of vertically aligned reduced titania nanotubes coated with Mn2O3 by reverse pulse electrodeposition

Nurul Asma Samsudin; Zulkarnain Zainal; Hong Ngee Lim; Yusran Sulaiman; Sook-Keng Chang; Ying-Chin Lim; Asmaa Kadim Ayal; Wardatun Nadrah Mohd Amin

doi:10.1039/c8ra03513j

Capacitive performance of vertically aligned reduced titania nanotubes coated with Mn₂O₃ by reverse pulse electrodeposition

RSC Adv. 2018 Jun 25;8(41):23040-23047. doi: 10.1039/c8ra03513j. eCollection 2018 Jun 21.

Authors

Nurul Asma Samsudin¹, Zulkarnain Zainal^{1

2}, Hong Ngee Lim^{1

2}, Yusran Sulaiman^{1

3}, Sook-Keng Chang^{1

2}, Ying-Chin Lim⁴, Asmaa Kadim Ayal^{1

5}, Wardatun Nadrah Mohd Amin¹

Affiliations

¹ Department of Chemistry, Faculty of Science, Universiti Putra Malaysia 43400 UPM Serdang Selangor Malaysia zulkar@upm.edu.my +60389466775.
² Materials Synthesis and Characterization Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia 43400 UPM Serdang Selangor Malaysia.
³ Functional Devices Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia 43400 UPM Serdang Selangor Malaysia.
⁴ School of Chemistry and Environmental, Faculty of Applied Sciences, Universiti Teknologi MARA 40450 Shah Alam Selangor Malaysia.
⁵ Department of Chemistry, College of Science for Women, University of Baghdad Baghdad Iraq.

Abstract

In this study, a composite material, manganese oxide/reduced titania nanotubes (Mn₂O₃/R-TNTs), was synthesized through incorporation of Mn₂O₃ onto R-TNTs via the reverse pulse electrodeposition technique. The influence of pulse reverse duty cycles on the morphological, structural and electrochemical performance of the surface was studied by varying the applied duty cycle from 10% to 90% for 5 min total on-time at an alternate potential of -0.90 V (E _on) and 0.00 V (E _off). FESEM analysis revealed the uniform deposition of Mn₂O₃ on the circumference of the nanotubes. The amount of Mn₂O₃ loaded onto the R-TNTs increased as a higher duty cycle was applied. Cyclic voltammetry and galvanostatic charge-discharge tests were employed to elucidate the electrochemical properties of all the synthesized samples in 1 M KCl. The specific capacitance per unit area was greatly enhanced upon the incorporation of Mn₂O₃ onto R-TNTs, but showed a decrease as a high duty cycle was applied. This proved that low amounts of Mn₂O₃ loading enhanced the facilitation of the active ions for charge storage purposes. The optimized sample, Mn₂O₃/R-TNTs synthesized at 10% duty cycle, exhibited high specific capacitance of 18.32 mF cm^-2 at a current density of 0.1 mA cm^-2 obtained from constant current charge-discharge measurements. This revealed that the specific capacitance possessed by Mn₂O₃/R-TNTs synthesized at 10% duty cycle was 6 times higher than bare R-TNTs.