Enhanced photoelectrochemical water splitting activity of carbon nanotubes@TiO2 nanoribbons in different electrolytes

Ashour M Ahmed; Fatma Mohamed; Abdallah M Ashraf; Mohamed Shaban; Aftab Aslam Parwaz Khan; Abdullah M Asiri

doi:10.1016/j.chemosphere.2019.124554

Enhanced photoelectrochemical water splitting activity of carbon nanotubes@TiO₂ nanoribbons in different electrolytes

Chemosphere. 2020 Jan:238:124554. doi: 10.1016/j.chemosphere.2019.124554. Epub 2019 Aug 12.

Authors

Ashour M Ahmed¹, Fatma Mohamed², Abdallah M Ashraf², Mohamed Shaban³, Aftab Aslam Parwaz Khan⁴, Abdullah M Asiri⁵

Affiliations

¹ Nanophotonics and Applications (NPA) Lab, Physics Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62514, Egypt.
² Nanophotonics and Applications (NPA) Lab, Physics Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62514, Egypt; Polymer Research Laboratory, Chemistry Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62514, Egypt.
³ Nanophotonics and Applications (NPA) Lab, Physics Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62514, Egypt. Electronic address: mssfadel@yahoo.com.
⁴ Center of Excellence for Advanced Materials Research and Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, 21589, P.O. Box 80203, Saudi Arabia. Electronic address: draapk@gmail.com.
⁵ Center of Excellence for Advanced Materials Research and Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, 21589, P.O. Box 80203, Saudi Arabia.

PMID: 31421463
DOI: 10.1016/j.chemosphere.2019.124554

Abstract

Hydrogen production from water splitting by a photocatalytic process is one way that can be used to solve global problems related to energy depletion and environmental pollution. This work aims to design and characterize a novel photocatalyst nanohybrid carbon nanotubes@TiO₂ nanoribbons (CNTs@TNRs) for enhanced photoelectrochemical (PEC) water splitting in different electrolytes under visible light irradiance. Here, hydrothermal and chemical vapor deposition (HT-CVD) were combined to grow CNTs @ the nanopits of TNRs producing network of nanohybrid CNTs@TNRs. The structural, morphological, optical, and photocatylatic properties of the TNRs and CNTs@TNRs nanohybrid were characterized by different techniques. The crystallite size is increased from 14.86 nm for TNRs to 21.61 nm for CNTs@TNRs nanohybrid. The CNTs@TNRs nanohybrid has well-resolved nanopits on the surface of the TNRs with an average diameter of 10 nm. The absorption edge of CNTs@TNRs relative to TNRs was strongly shifted to the visible light region. The band gap values are 3.78 and 2.07 eV for TNRs and CNTs@TNRs, respectively. The TNRs and CNTs@TNRs were used for the photocatalytic water splitting under visible light irradiance in Na₂S₂O₃, HCl and KOH electrolytes of different concentrations. The calculated incident photon-to-current conversion efficiency (IPCE) was 97% at 510 nm. These values are higher than those previously reported for different photoelectrodes. The number of hydrogen moles was calculated to be 300 μmol h^-1 cm^-2. Therefore, our work demonstrates a feasible route for efficient PEC water splitting under sunlight irradiation utilizing the novel CNTs@TNRs photocatalyst.

Keywords: Carbon nanotubes; Photoelectrochemical water splitting; TiO(2) nanoribbons.

MeSH terms

Electrochemistry / methods*
Electrolytes / chemistry*
Hydrogen / metabolism*
Light
Nanotubes, Carbon / chemistry*
Photochemical Processes / radiation effects*
Titanium / chemistry*
Water / metabolism*

Substances

Electrolytes
Nanotubes, Carbon
Water
titanium dioxide
Hydrogen
Titanium