Facile Preparation of a Bispherical Silver-Carbon Photocatalyst and Its Enhanced Degradation Efficiency of Methylene Blue, Rhodamine B, and Methyl Orange under UV Light

Md Akherul Islam; Jeasmin Akter; Insup Lee; Santu Shrestha; Anil Pandey; Narayan Gyawali; Md Monir Hossain; Md Abu Hanif; Se Gyu Jang; Jae Ryang Hahn

doi:10.3390/nano12223959

Facile Preparation of a Bispherical Silver-Carbon Photocatalyst and Its Enhanced Degradation Efficiency of Methylene Blue, Rhodamine B, and Methyl Orange under UV Light

Nanomaterials (Basel). 2022 Nov 10;12(22):3959. doi: 10.3390/nano12223959.

Authors

Md Akherul Islam¹, Jeasmin Akter², Insup Lee², Santu Shrestha², Anil Pandey², Narayan Gyawali², Md Monir Hossain^{1

3}, Md Abu Hanif¹, Se Gyu Jang³, Jae Ryang Hahn^{2

4}

Affiliations

¹ Department of Bioactive Material Sciences, Jeonbuk National University, Jeonju 54896, Korea.
² Department of Chemistry, Research Institute of Physics and Chemistry, Jeonbuk National University, Jeonju 54896, Korea.
³ Functional Composite Materials Research Center, Institute of Advanced Composites Materials, Korea Institute of Science and Technology, Wanju, Jeonbuk 55324, Korea.
⁴ Textile Engineering, Chemistry and Science, North Carolina State University 2401 Research Dr., Raleigh, NC 27695-8301, USA.

Abstract

The combination of organic and inorganic materials is attracting attention as a photocatalyst that promotes the decomposition of organic dyes. A facile thermal procedure has been proposed to produce spherical silver nanoparticles (AgNPs), carbon nanospheres (CNSs), and a bispherical AgNP-CNS nanocomposite. The AgNPs and CNSs were each synthesized from silver acetate and glucose via single- and two-step annealing processes under sealed conditions, respectively. The AgNP-CNS nanocomposite was synthesized by the thermolysis of a mixture of silver acetate and a mesophase, where the mesophase was formed by annealing glucose in a sealed vessel at 190 °C. The physicochemical features of the as-prepared nanoparticles and composite were evaluated using several analytical techniques, revealing (i) increased light absorption, (ii) a reduced bandgap, (iii) the presence of chemical interfacial heterojunctions, (iv) an increased specific surface area, and (v) favorable band-edge positions of the AgNP-CNS nanocomposite compared with those of the individual AgNP and CNS components. These characteristics led to the excellent photocatalytic efficacy of the AgNP-CNS nanocomposite for the decomposition of three pollutant dyes under ultraviolet (UV) radiation. In the AgNP-CNS nanocomposite, the light absorption and UV utilization capacity increased at more active sites. In addition, effective electron-hole separation at the heterojunction between the AgNPs and CNSs was possible under favorable band-edge conditions, resulting in the creation of reactive oxygen species. The decomposition rates of methylene blue were 95.2, 80.2, and 73.2% after 60 min in the presence of the AgNP-CNS nanocomposite, AgNPs, and CNSs, respectively. We also evaluated the photocatalytic degradation efficiency at various pH values and loadings (catalysts and dyes) with the AgNP-CNS nanocomposite. The AgNP-CNS nanocomposite was structurally rigid, resulting in 93.2% degradation of MB after five cycles of photocatalytic degradation.

Keywords: Z-scheme process; bispherical nanocomposite; carbon nanospheres; photocatalysts; reduced bandgap; spherical silver nanoparticles.

Abstract

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