Highly efficient visible light active Cu-ZnO/S-g-C3N4 nanocomposites for efficient photocatalytic degradation of organic pollutants

Mohsin Javed; Muhammad Azam Qamar; Sammia Shahid; Hashem O Alsaab; Salma Asif

doi:10.1039/d1ra07203j

Highly efficient visible light active Cu-ZnO/S-g-C₃N₄ nanocomposites for efficient photocatalytic degradation of organic pollutants

RSC Adv. 2021 Nov 19;11(59):37254-37267. doi: 10.1039/d1ra07203j. eCollection 2021 Nov 17.

Authors

Mohsin Javed¹, Muhammad Azam Qamar¹, Sammia Shahid¹, Hashem O Alsaab², Salma Asif¹

Affiliations

¹ Department of Chemistry, School of Science, University of Management and Technology Lahore 54770 Pakistan mohsin.javed@umt.edu.pk qamariub@gmail.com.
² Department of Pharmaceutics and Pharmaceutical Technology, Taif University P. O. Box 11099 Taif 21944 Saudi Arabia.

Abstract

The photocatalytic activity of photocatalysts is severely hampered by limited visible light harvesting and unwanted fast recombination of photogenerated e^- and h⁺. In the current study, the photocatalytic efficiency of Cu-ZnO/S-g-C₃N₄ (CZS) nanocomposites was investigated against MB dye. The composite materials were designed via chemical co-precipitation method and characterised by important analytical techniques. Distinctive heterojunctions developed between S-g-C₃N₄ and Cu-ZnO in the CZS composite were revealed by TEM. The synthesized composites exhibit a huge number of active sites, a large surface area, a smaller size and better visible light absorption. The considerable enhancement in the photocatalytic activity of CZS nanocomposites might be accredited to the decay in the e-h pair recombination rate and a red shift in the visible region, as observed by PL and optical analysis, respectively. Furthermore, the metal (Cu) doping into the S-g-C₃N₄/ZnO matrix created exemplary interfaces between ZnO and S-g-C₃N₄, and maximized the photocatalytic activity of CZS nanocomposites. In particular, CZS nanocomposites synthesized by integrating 25% S-g-C₃N₄ with 4% Cu-ZnO (CZS-25 NCs) exhibited the 100% photocatalytic degradation of MB in 60 minutes under sunlight irradiation. After six cycles, the photocatalytic stability of CZS-25 NCs was excellent. Likewise, a plausible MB degradation mechanism is proposed over CZS-25 NCs based on photoluminescence and reactive species scavenger test observation. The current research supports the design of novel composites for the photocatalytic disintegration of organic contaminants.