Conversion of Sewage Water into H2 Gas Fuel Using Hexagonal Nanosheets of the Polyaniline-Assisted Deposition of PbI2 as a Nanocomposite Photocathode with the Theoretical Qualitative Ab-Initio Calculation of the H2O Splitting

N M A Hadia; Mohammed A H Khalafalla; Fatma M Abdel Salam; Ashour M Ahmed; Mohamed Shaban; Aljawhara H Almuqrin; Ali Hajjiah; H A Hanafi; Mansoor Alruqi; Abdel-Hamid I Mourad; Mohamed Rabia

doi:10.3390/polym14112148

Conversion of Sewage Water into H₂ Gas Fuel Using Hexagonal Nanosheets of the Polyaniline-Assisted Deposition of PbI₂ as a Nanocomposite Photocathode with the Theoretical Qualitative Ab-Initio Calculation of the H₂O Splitting

Polymers (Basel). 2022 May 25;14(11):2148. doi: 10.3390/polym14112148.

Authors

N M A Hadia^{1

2}, Mohammed A H Khalafalla³, Fatma M Abdel Salam^{4

5}, Ashour M Ahmed⁴, Mohamed Shaban^{4

6}, Aljawhara H Almuqrin⁷, Ali Hajjiah⁸, H A Hanafi^{9

10}, Mansoor Alruqi¹¹, Abdel-Hamid I Mourad^{12

13}, Mohamed Rabia^{4

5}

Affiliations

¹ Physics Department, College of Science, Jouf University, Sakaka P.O. Box 2014, Al-Jouf, Saudi Arabia.
² Basic Sciences Research Unit, Jouf University, Sakaka P.O. Box 2014, Al-Jouf, Saudi Arabia.
³ Department of Physics, Faculty of Science, Taibah University, Yanbu P.O. Box 41315, Saudi Arabia.
⁴ Nanophotonics and Applications Lab, Physics Department, Faculty of Science, Beni-Suef University, Beni-Suef 62514, Egypt.
⁵ Nanomaterials Science Research Laboratory, Chemistry Department, Faculty of Science, Beni-Suef University, Beni-Suef 62514, Egypt.
⁶ Physics Department, Faculty of Science, Islamic University of Madinah, Madinah 42351, Saudi Arabia.
⁷ Department of Physics, College of Science, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia.
⁸ Electrical Engineering Department, College of Engineering and Petroleum, Kuwait University, Safat 13113, Kuwait.
⁹ Chemistry Department, College of Science and Humanities Al-Quwayiyah, Shaqra University, Al-Quwayiyah 19257, Saudi Arabia.
¹⁰ Cylotron Project, Nuclear Research Center, Egyptian Atomic Energy Authority, Cairo P.O. Box 13759, Egypt.
¹¹ Department of Mechanical Engineering, College of Engineering, Shaqra University, Riyadh 11911, Saudi Arabia.
¹² Mechanical and Aerospace Engineering Department, College of Engineering, United Arab Emirate University, Al Ain 15551, United Arab Emirates.
¹³ Mechanical Design Department, Faculty of Engineering, Helwan University, Cairo 11795, Egypt.

Abstract

This study is very promising for providing a renewable enrgy (H₂ gas fuel) under the elctrochemical splitting of the wastwater (sewage water). This study has double benefits: hydrogen generation and contaminations removel. This study is carried out on sewage water, third stage treated, from Beni-Suef city, Egypt. Antimony tin oxide (ATO)/polyaniline (PANI)/PbI₂ photoelectrode is prepared through the in situ oxidative polymerization of PANI on ATO, then PANI is used as an assistant for PbI₂ deposition using the ionic adsorption deposition method. The chemical structural, morphological, electrical, and optical properties of the composite are confirmed using different analytical tools such as X-ray diffreaction (XRD), scanning electron microscope (SEM), transmision electron microscope (TEM), Fourier-transform infrared spectroscopy (FTIR), and UV-Vis spectroscopy. The prepared PbI₂ inside the composite has a crystal size of 33 nm (according to the peak at 12.8°) through the XRD analyses device. SEM and TEM confirm the hexagonal PbI₂ sheets embedded on the PANI nanopores surface. Moreover, the bandgap values are enhanced very much after the composite formation, in which the bandgap values for PANI and PANI/PbI₂ are 3 and 2.51 eV, respectively. The application of ATO/PANI/PbI₂ nanocomposite electrode for sewage splitting and H₂ generation is carried out through a three-electrode cell. The measurements carreid out using the electrocehical worksattion under th Xenon lamp (100 mW.cm^-2). The produced current density (J_ph) is 0.095 mA.cm^-2 at 100 mW.cm^-2 light illumination. The photoelectrode has high reproducibility and stability, in which and the number of H₂ moles is 6 µmole.h^-1.cm^-1. The photoelectrode response to different monochromatic light, in which the produced J_ph decreases from 0.077 to 0.072 mA.cm^-2 with decreasing of the wavelengths from 390 to 636 nm, respectively. These values confirms the high response of the ATO/PANI/PbI₂ nanocomposite electrode for the light illuminaton and hydrogen genration under broad light region. The thermodynamic parameters: activation energy (Ea), enthalpy (ΔH*), and entropy (ΔS*) values are 7.33 kJ/mol, -4.7 kJ/mol, and 203.3 J/mol.K, respectively. The small values of ΔS* relted to the high sesnivity of the prepared elctrode for the water splitting and then the hydrogen gneration. Finally, a theoretical study was mentioned for calculation geometry, electrochemical, and thermochemistry properties of the polyaniline/PbI₂ nanocomposite as compared with that for the polyaniline.

Keywords: PbI2; hydrogen generation; nanocomposite; polyaniline; sewage water; water splitting.

Grants and funding

DSR-2021-03-0315/Al Jouf University