The Role of Nitrogen-Doped TiO 2 Supported by Platinum Catalyst Synthesized via Various Mode Preparations for Photocatalytic Enhancement

• Published in: Nanomaterials (Basel, Switzerland) Switzerland), 2022-11, Vol.12 (22)
• Main Authors: Natar, Nadiah Sabihah, Ghani, Nureel Imanina Abdul, Hamzah, Siti Raihan, Rosli, Muhammad Afiq, Muhamad, Nur Aien, Azami, Mohammad Saifulddin, Ishak, Mohd Azlan Mohd, Razak, Sharin, Nawawi, Wan Izhan
• Format: Article
• Language: English
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano12223998

The limitations of TiO as a photocatalyst such as the larger bandgap energy, which only activates under the UV region, give a lower photocatalytic activity. This study reports the role of the N and Pt co-dopant on the modification of the TiO photocatalyst for photocatalytic degradation of methylene blue dye under different mode preparations, i.e., sequential and vice-versa modes. The sequential mode preparation of the N and Pt co-dopant TiO photocatalyst consisted of the initial preparation of the N-doped TiO (N-TiO ) under the calcination method, which was then further doped with platinum (Pt) through the photodeposition process labeled as NP -TiO , while the vice-versa mode was labeled as PN -TiO . About 1.58 wt.% of N element was found in the NP -TiO photocatalyst, while there was no presence of N element detected in PN -TiO , confirmed through an elemental analyzer (CHNS-O) and (EDX) analysis. The optimum weight percentage of Pt for both modes was detected at about ±2.0 wt.%, which was confirmed by inductively coupled plasma-emission spectroscopy (ICP-OES). The photoactivity under methylene blue (MB) dye degradation of the NP -TiO photocatalyst was 2 and 1.5 times faster compared to the unmodified TiO and PN -TiO , where the photodegradation rates were, ca., 0.065 min and 0.078 min , respectively. This was due to the N elements being incorporated with the TiO lattice, which was proven by UV-Vis/DRS where the bandgap energy of NP -TiO was reduced from 3.2 eV to 2.9 eV. In addition, the N generated a stronger PL signal due to the formation of oxygen vacancies defects on the surface of the NP -TiO photocatalyst. The higher specific surface area as well as higher pore volume for the NP -TiO photocatalyst enhanced its photocatalytic activity. Moreover, the NP -TiO showed the lowest COD value, and it was completely mineralized after 7 h of light irradiation. The preparation order did not affect the Pt dopant but did for the N element. Therefore, it is significant to investigate different mode preparations of the N and Pt co-dopant for the modification of TiO to produce a good-quality photocatalyst for photocatalytic study under the photodegradation of MB dye.