Plasmonic Ag@ZIF-8 Monolith for Enhanced Visible-Light Photocatalytic Degradation of Methylene Blue
- 1Midlands State University , , Private Bag 9055, Senga Road , ,
- 2University of Pretoria , , Private Bag X20 , ,
Abstract
Water contamination by organic dyes remains a major environmental challenge due to their toxicity, persistence, and resistance to conventional treatment methods. In this study, a plasmonic silver-modified metal–organic framework monolith was successfully synthesized via a sol–gel approach. Incorporation of Ag species during gel formation ensured homogeneous distribution within the ZIF-8 framework, which was followed by in situ chemical reduction to produce a reduced material denoted Ag0@ZIF-8. Comprehensive characterization confirmed the structural integrity of the ZIF-8 framework, with TEM revealing electron-dense silver domains and UV–vis DRS showing enhanced visible-light absorption associated with localized surface plasmon resonance (LSPR). The photocatalytic performance of Ag0@ZIF-8 was evaluated through the degradation of methylene blue under visible light. The catalyst exhibited significantly enhanced activity compared to pristine ZIF-8 and the Ag+@ZIF-8 monolith, achieving a maximum degradation efficiency of 90.4 ± 1.0% under optimized conditions (pH 8, 60 mg of catalyst, 60 min irradiation). Kinetic studies confirmed pseudo-first-order behavior with a rate constant of 0.0358 min–1 (R2 = 0.9923). Scavenger experiments revealed that superoxide radicals (•O2–) played the dominant role in methylene blue degradation, with hydroxyl radicals (•OH) and photogenerated holes (h+) making secondary contributions. The Ag0@ZIF-8 monolith also demonstrated good reusability, retaining over 75% of its initial activity after five cycles. Overall, this work highlights the synergistic interaction between plasmonic silver species and the ZIF-8 monolith, resulting in enhanced visible-light-driven photocatalytic degradation of organic pollutants, offering a promising strategy for wastewater treatment applications.
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BibTeX
@article{tshuma2026plasmonic,
title = {{Plasmonic Ag@ZIF-8 Monolith for Enhanced Visible-Light Photocatalytic Degradation of Methylene Blue}},
author = {Piwai Tshuma and Mercy Chaparadza and Thapelo Seimela and Mmantsae Diale and Nicola Vimbainashe Poshayi and Linia Gedi Marazani and Gift Mehlana},
journal = {ACS Omega},
year = {2026},
month = oct,
doi = {10.1021/acsomega.6c05428},
url = {https://pubs.acs.org/acsodf/article/11/41/63033/5448425/Plasmonic-Ag-ZIF-8-Monolith-for-Enhanced-Visible},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Plasmonic Ag@ZIF-8 Monolith for Enhanced Visible-Light Photocatalytic Degradation of Methylene Blue
AU - Piwai Tshuma
AU - Mercy Chaparadza
AU - Thapelo Seimela
AU - Mmantsae Diale
AU - Nicola Vimbainashe Poshayi
AU - Linia Gedi Marazani
AU - Gift Mehlana
PY - 2026
DA - 2026/10/09
JO - ACS Omega
DO - 10.1021/acsomega.6c05428
UR - https://pubs.acs.org/acsodf/article/11/41/63033/5448425/Plasmonic-Ag-ZIF-8-Monolith-for-Enhanced-Visible
AB - Water contamination by organic dyes remains a major environmental challenge due to their toxicity, persistence, and resistance to conventional treatment methods. In this study, a plasmonic silver-modified metal–organic framework monolith was successfully synthesized via a sol–gel approach. Incorporation of Ag species during gel formation ensured homogeneous distribution within the ZIF-8 framework, which was followed by in situ chemical reduction to produce a reduced material denoted Ag0@ZIF-8. Comprehensive characterization confirmed the structural integrity of the ZIF-8 framework, with TEM revealing electron-dense silver domains and UV–vis DRS showing enhanced visible-light absorption associated with localized surface plasmon resonance (LSPR). The photocatalytic performance of Ag0@ZIF-8 was evaluated through the degradation of methylene blue under visible light. The catalyst exhibited significantly enhanced activity compared to pristine ZIF-8 and the Ag+@ZIF-8 monolith, achieving a maximum degradation efficiency of 90.4 ± 1.0% under optimized conditions (pH 8, 60 mg of catalyst, 60 min irradiation). Kinetic studies confirmed pseudo-first-order behavior with a rate constant of 0.0358 min–1 (R2 = 0.9923). Scavenger experiments revealed that superoxide radicals (•O2–) played the dominant role in methylene blue degradation, with hydroxyl radicals (•OH) and photogenerated holes (h+) making secondary contributions. The Ag0@ZIF-8 monolith also demonstrated good reusability, retaining over 75% of its initial activity after five cycles. Overall, this work highlights the synergistic interaction between plasmonic silver species and the ZIF-8 monolith, resulting in enhanced visible-light-driven photocatalytic degradation of organic pollutants, offering a promising strategy for wastewater treatment applications.
SN - 2470-1343
ER -