Near-Infrared (NIR) Silver Sulfide (Ag2S) Semiconductor Photocatalyst Film for Degradation of Methylene Blue Solution

Zahrah Ramadlan Mubarokah; Norsuria Mahmed; Mohd Natashah Norizan; Ili Salwani Mohamad; Mohd Mustafa Al Bakri Abdullah; Katarzyna Błoch; Marcin Nabiałek; Madalina Simona Baltatu; Andrei Victor Sandu; Petrica Vizureanu

doi:10.3390/ma16010437

Near-Infrared (NIR) Silver Sulfide (Ag₂S) Semiconductor Photocatalyst Film for Degradation of Methylene Blue Solution

Materials (Basel). 2023 Jan 3;16(1):437. doi: 10.3390/ma16010437.

Authors

Zahrah Ramadlan Mubarokah¹, Norsuria Mahmed^{1

2}, Mohd Natashah Norizan^{2

3}, Ili Salwani Mohamad^{2

3}, Mohd Mustafa Al Bakri Abdullah^{1

2}, Katarzyna Błoch⁴, Marcin Nabiałek⁴, Madalina Simona Baltatu⁵, Andrei Victor Sandu^{5

6

7}, Petrica Vizureanu^{5

8}

Affiliations

¹ Faculty of Chemical Engineering & Technology, Universiti Malaysia Perlis (UniMAP), Arau 01000, Malaysia.
² Centre of Excellence Geopolymer and Green Technology (CEGeoGTech), Universiti Malaysia Perlis (UniMAP), Arau 01000, Malaysia.
³ Faculty of Electronic Engineering & Technology, Universiti Malaysia Perlis (UniMAP), Arau 02600, Malaysia.
⁴ Faculty of Mechanical Engineering and Computer Science, Częstochowa University of Technology, 42-201 Częstochowa, Poland.
⁵ Department of Technologies and Equipments for Materials Processing, Faculty of Materials Science and Engineering, Gheorghe Asachi Technical University of Iaşi, Blvd. Mangeron, No. 51, 700050 Iasi, Romania.
⁶ National Institute for Research and Development in Environmental Protection INCDPM, Splaiul Independentei 294, 060031 Bucharest, Romania.
⁷ Romanian Inventors Forum, Str. Sf. P. Movila 3, 700089 Iasi, Romania.
⁸ Technical Sciences Academy of Romania, Dacia Blvd 26, 030167 Bucharest, Romania.

Abstract

A silver sulfide (Ag₂S) semiconductor photocatalyst film has been successfully synthesized using a solution casting method. To produce the photocatalyst films, two types of Ag₂S powder were used: a commercialized and synthesized powder. For the commercialized powder (CF/comAg₂S), the Ag₂S underwent a rarefaction process to reduce its crystallite size from 52 nm to 10 nm, followed by incorporation into microcrystalline cellulose using a solution casting method under the presence of an alkaline/urea solution. A similar process was applied to the synthesized Ag₂S powder (CF/syntAg₂S), resulting from the co-precipitation process of silver nitrate (AgNO₃) and thiourea. The prepared photocatalyst films and their photocatalytic efficiency were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and UV-visible spectroscopy (UV-Vis). The results showed that the incorporation of the Ag₂S powder into the cellulose films could reduce the peak intensity of the oxygen-containing functional group, which indicated the formation of a composite film. The study of the crystal structure confirmed that all of the as-prepared samples featured a monoclinic acanthite Ag₂S structure with space group P₂₁/C. It was found that the degradation rate of the methylene blue dye reached 100% within 2 h under sunlight exposure when using CF/comAg₂S and 98.6% for the CF/syntAg₂S photocatalyst film, and only 48.1% for the bare Ag₂S powder. For the non-exposure sunlight samples, the degradation rate of only 33-35% indicated the importance of the semiconductor near-infrared (NIR) Ag₂S photocatalyst used.

Keywords: cellulose film; methylene blue; near-infrared irradiation; photocatalysis; silver sulfide.

Grants and funding

This work was financially supported by the Fundamental Research Grant Scheme FRGS/1/2021/TK0/UNIMAP/02/33 from the Ministry of Education Malaysia (MOE) and by Gheorghe Asachi Technical University of Iasi—TUIASI Romania, Scientific Research Funds, FCSU-2022.