Now showing 1 - 9 of 9
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The study and preparation of polyaniline-graphene oxide as robust counter electrode for dye-sensitized solar cells

2022-05-18 , Mohd Fairul Sharin Abdul Razak , Shukor A.A. , Mohd Nazry Salleh , Nawawi W.I. , Norhayati Sabani , Badri A.

The study of alternative materials and platinum-free counter electrodes (CE) for the development of dye- sensitized solar cells (DSSC) has been highlighted nowadays. Polyaniline (PANI) is one of the most common conducting polymers applied in electrochemical energy storage and conversion technologies such as supercapacitors, rechargeable batteries and fuel cells. However, PANI counter electrodes lack long-term stability due to their low surface area and large volume changes during the release of ions. In that regard, this research work focused on the modification of protonated PANI with graphene oxide (GO) at various weight percentages (wt%) in order to obtain robust CE in DSSC. The structure and formation of PANI, GO and PANI/GO were characterized by Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) analyses. The absorption spectra showed all the characteristic bands of GO, PANI(ES) and PANI/GO. Meanwhile, the incorporation of GO into PANI has enhanced the crystallinity of the composite. As a result, power conversion efficiency (PCE%) of the device with PANI/GO 3 wt% as the counter electrode reaches 6.39%. The excellent photoelectric properties, simple preparation procedure and inexpensive cost allow the PANI/GO electrode to be a credible alternative for DSSCs.

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Synergistic effect of agarose biopolymer gel electrolyte with modified TiO2 for low-cost electrochemical device applications

2023-09-01 , Badri A. , Mohd Fairul Sharin Abdul Razak , Nawawi W.I. , Norhayati Sabani , Mohd Natashah Norizan , Abul Shukor A.

The effect of different concentrations of agarose gel electrolyte in a low-cost fabrication of DSSC system was investigated. The modified DSSC was fabricated by a sandwiched method using ITO glass plates as substrates. TiO2-Graphene-coated glass plate was used as the working electrode while PANI-GO-coated glass plate works as a counter electrode, respectively. Both electrodes were separated by agarose gel mixture with KI solution as gel biopolymer electrolyte. The FTIR result showed that peaks of agarose are well observed in the KI-agarose spectra. In the XRD analysis, the combination of KI-agarose has reduced the crystallinity of agarose which was good for ionic conductivity value. The addition of agarose in KI solution also produced a fine channel to facilitate the ionic transfer in electrolyte. The behaviour of electrochemical properties of the system was observed using AC impedance spectroscopy based on the Nyquist plot. From the plot, three semicircles were observed as the responses at different frequencies. It was observed that the 5 wt% agarose electrolyte in DSSC system was selected as the optimum loading exhibiting the lowest resistivity ensuring the faster electron transfer and giving the ionic conductivity of 9.04 × 10−1 S/cm. The ionic conductivity of the system was dropped at 2.21 × 10−1 S/cm as the percentage of agarose was increase to 6 wt%.

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Low temperature prepared N doped TiO2photodegradation of janus green B

2020-11-24 , Othman S.A. , Zainon S.N. , Abdullah M.F. , Nawawi W.I. , Ikhwan S. , Mohd Fairul Sharin Abdul Razak

N doped titanium dioxide (TiO2) was prepared under low temperature calcination of TiO2 Degussa P25 powder and urea at various mixing ratios. Muffle furnace was used as heating media with the temperature used in the range of 300 to 500 C. The prepared N doped TiO2 was characterized by using UV-Vis diffuse reflectance spectroscopy (DRS), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM). It was observed that N doped TiO2 prepared at 0.5 g urea under the 400 C calcination process (named as U2-400) is the optimum photocatalyst sample with the highest rate removal of Janus green B (JG) dye. The U2-400 had goes the photodegradation rate removal at 0.1071 min-1 where it is 3.5 times faster compared to unmodified TiO2 sample. The high photodegradation rate removal for U2-400 was due to the N incorporated with TiO2 in U2-400 photocatalyst which narrowed the bandgap energy from 3.2 to 3.0 eV as observed by UV-Vis DRS spectra. This shows the U2-400 sample has increased its photocatalytic activity since it has become more active under wider an optical response compared to the unmodified TiO2

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The role of Nitrogen-Doped TiO2 supported by platinum catalyst synthesized via various mode preparations for photocatalytic nnhancement

2022-11-01 , Natar N.S. , Ghani N.I.A. , Hamzah S.R. , Rosli M.A. , Muhamad N.A. , Azami M.S. , Ishak M.A.M. , Mohd Fairul Sharin Abdul Razak , Nawawi W.I.

The limitations of TiO2 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 TiO2 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 TiO2 photocatalyst consisted of the initial preparation of the N-doped TiO2 (N-TiO2) under the calcination method, which was then further doped with platinum (Pt) through the photodeposition process labeled as NPseq-TiO2, while the vice-versa mode was labeled as PNrev-TiO2. About 1.58 wt.% of N element was found in the NPseq-TiO2 photocatalyst, while there was no presence of N element detected in PNrev-TiO2, 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 NPseq-TiO2 photocatalyst was 2 and 1.5 times faster compared to the unmodified TiO2 and PNrev-TiO2, where the photodegradation rates were, ca., 0.065 min−1 and 0.078 min−1, respectively. This was due to the N elements being incorporated with the TiO2 lattice, which was proven by UV-Vis/DRS where the bandgap energy of NPseq-TiO2 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 NPseq-TiO2 photocatalyst. The higher specific surface area as well as higher pore volume for the NPseq-TiO2 photocatalyst enhanced its photocatalytic activity. Moreover, the NPseq-TiO2 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 TiO2 to produce a good-quality photocatalyst for photocatalytic study under the photodegradation of MB dye.

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Preparation of water-base immobilized N doped TiO2 using DSAT technique for photocatalytic degradation of methylene blue dye

2022-01-01 , Natar N.S. , Ikhwan S. , Nazeri N.S. , Hamzah S.R. , Rosli M.A. , Ghani N.I. , Ishak M.A.M. , Mohd Fairul Sharin Abdul Razak , Azami M.S. , Nawawi W.I.

Photocatalytic degradation of TiO2 photocatalyst under suspension mode has widely been studied among researchers. However, the application is limited due to the complexity in separation and non-recyclability of photocatalyst. Immobilization is one of the promising methods to overcome this problem. Most of the prepared immobilization modes showed lower photocatalytic activity compared with the suspension due to the chemical reaction of solvent with modified TiO2. Therefore, a free solvent or water-base preparation of immobilized TiO2 is critical in retaining its photocatalytic activity. Immobilization via double-sided adhesive tape (DSAT) was introduced previously by our research team, it works the best of others in replacing polymer binder in immobilization system making it a free solvent preparation process. The aim of this research is to prepare immobilized unmodified TiO2 and N doped TiO2 by using water-base DSAT technique. The presence of N element was detected for all modified N doped TiO2 samples confirmed by FTIR and EDX analysis. The N incorporated in modified TiO2 has reduced the band gap energy from 3.0 to 2.8 eV as observed by UV–Vis/DRS analysis. This explained the photoactivity under MB dye degradation is 2.1 times faster under N doped TiO2 where the photodegradation rate for unmodified and optimum N doped TiO2 (TN1-45) were 0.065 and 0.138 min−1 respectively. Immobilized TiO2/DSAT and TN1-450/DSAT have shown a significant photocatalytic performance where it was only reduced to 15% from suspension to immobilized mode. It can be considered higher performance as compared to the normal immobilization under solvent. It also better than suspension mode by considering of its reusability that able to sustain the photoactivity of immobilized TN1-450/DSAT for at least for 12 cycles.

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Graphene-modified TiO2as photoanode using agarose gel electrolyte for dye-sensitized solar cell

2022-05-18 , Mohd Fairul Sharin Abdul Razak , Afzalina Badri , Nawawi W.I. , Norhayati Sabani , Mohammad Kahar Ab Wahab , Amira Abul Shukor

A newly developed biopolymer agarose gel electrolyte along with titanium dioxide-graphene (TiO2-G) as a photoanode in Dye-Sensitized Solar Cell (DSSC) was prepared and investigated towards green approaches and electrolyte stability. To develop a biopolymer electrolyte, potassium iodide was added to the agarose biopolymer matrix to produce a gel electrolyte system. As for the photoanode, TiO2 with different graphene concentrations was prepared. It was recorded that the bandgap was reduced from 3.0 eV to 2.50 eV with the increasing graphene concentration. The formation of agarose gel electrolyte and TiO2-Graphene photoanode were determined by the FTIR analysis. Meanwhile, XRD analysis was conducted to identify the crystallinity of agarose gel electrolyte and TiO2-G affecting the performance of the cell. The XRD spectra measured in a range of 2θ from 5° to 80° showed a diffraction peak at 2θ = 22°, 25.5° and 36° for agarose gel electrolyte and 2θ = 24.88° for TiO2-Graphene. The results illustrated that the TiO2-G combination improves the crystallinity and thus exhibits higher surface area and mesoporous structure for better electrical conductivity and simultaneously strikes the performance stability of DSSC.

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Preparation of a Visible light Active N-doped TiO2Photocatalyst using Microwave Irradiation Technique

2020-11-24 , Nawawi W.I. , Mohd Fairul Sharin Abdul Razak , Fazeri

The dye wastewater which directly discharges without treatment process will affect the environment. The semiconductor like titanium dioxide (TiO2) has gained attention as most potential material for photocatalysis process to treat the dye wastewater with act as photocatalyst. However, this semiconductor has their limitation toward the photodegradation under visible light irradiation. In this study, TiO2 has been modified by doping with nitrogen (N) to improve the effectiveness under visible light irradiation. This simple prepared N-doped TiO2 was prepared by mixing of TiO2 powder with urea as N precursor under microwave irradiation instead of using muffle furnace as heating media. The nitogen was chemically bonded with TiO2 as proven by XPS analysis. N-doped TiO2 sample show active under visible light irradiation due to lower band gaps energy of sample observed by UV/Vis-DRS. An active photo response under visible light was observed from N-doped TiO2 with 80 minutes time irradiation to complete the reactive red 4 (RR4) color removal, while no photocatalytic degradation was observed from unmodified TiO2 under the same irradiation.

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The study and preparation of polyaniline-graphene oxide as robust counter electrode for dye-sensitized solar cells

2022-05-18 , Mohd Fairul Sharin Abdul Razak , Amira Abul Shukor , Mohd Nazry Salleh , Nawawi W.I. , Norhayati Sabani , Afzalina Badri

The study of alternative materials and platinum-free counter electrodes (CE) for the development of dye- sensitized solar cells (DSSC) has been highlighted nowadays. Polyaniline (PANI) is one of the most common conducting polymers applied in electrochemical energy storage and conversion technologies such as supercapacitors, rechargeable batteries and fuel cells. However, PANI counter electrodes lack long-term stability due to their low surface area and large volume changes during the release of ions. In that regard, this research work focused on the modification of protonated PANI with graphene oxide (GO) at various weight percentages (wt%) in order to obtain robust CE in DSSC. The structure and formation of PANI, GO and PANI/GO were characterized by Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) analyses. The absorption spectra showed all the characteristic bands of GO, PANI(ES) and PANI/GO. Meanwhile, the incorporation of GO into PANI has enhanced the crystallinity of the composite. As a result, power conversion efficiency (PCE%) of the device with PANI/GO 3 wt% as the counter electrode reaches 6.39%. The excellent photoelectric properties, simple preparation procedure and inexpensive cost allow the PANI/GO electrode to be a credible alternative for DSSCs.

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Effect of Photoetching Process onto Immobilized PANI/TiO2Films towards Photocatalytic Degradation of RR2 dye

2020-11-24 , Mohd Fairul Sharin Abdul Razak , Mohd Nazry Salleh , Nawawi W.I. , Natar N.

Polyaniline (PANI) and P-25 Titanium dioxide (TiO2) was fabricated as immobilized P-25TiO2/PANI/ENR/PVC film and reported on the photocatalytic study. PANI and TiO2 was immersed into the organic solvent and being coated onto glass plates under influenced of ENR/PVC polymeric binder by using a dip-coating method. It was found that, the removal of RR2 dye nearly good as suspension system after the pre-irradiation process. Based on COD and BET results, it showed that the optimum time of etching process was 7 hours irradiation time. This pre-irradiation process enhanced the removal of dye due to leached out of excessive binder and also exhibit visible light active after insertion of PANI into the immobilized system.