M/g-C3N4 (M=Ag, Au, and Pd) composite: synthesis via sunlight photodeposition and application towards the degradation of bisphenol A

• Published in: Environmental science and pollution research international Vol. 25; no. 25; pp. 25401 - 25412
• Main Authors: Hak, Chen Hong, Sim, Lan Ching, Leong, Kah Hon, Lim, Ping Feng, Chin, Yik Heng, Saravanan, Pichiah
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-09-2018; Springer Nature B.V
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Bisphenol A; Carbon nitride; Charge efficiency; Degradation; Deposition; Earth and Environmental Science; Ecotoxicology; Electron transfer; Environment; Environmental Chemistry; Environmental Health; Environmental science; Gold; Heavy metals; Irradiation; Nanoparticles; Noble metals; Palladium; Particle size; Photocatalysis; Radiation; Research Article; Silver; Sunlight; Superoxide; Waste Water Technology; Water Management; Water Pollution Control; X ray photoelectron spectroscopy; Bisphenol A; Noble metal; Natural sunlight; g-C; Photocatalysis; N
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-018-2632-8

In this work, natural sunlight successfully induced the deposition of gold (Au), silver (Ag), and palladium (Pd) nanoparticles (NPs) with 17.10, 9.07, and 12.70 wt% onto the surface of graphitic carbon nitride (g-C
3
N
4
). The photocatalytic evaluation was carried out by adopting Bisphenol A (BPA) as a pollutant under natural sunlight irradiation. The presence of noble metals was confirmed by EDX, HRTEM, and XPS analysis. The deposition of Ag NPs (7.9 nm) resulted in the degradation rate which was 2.15-fold higher than pure g-C
3
N
4
due to its relatively small particle size, contributing to superior charge separation efficiency. Au/g-C
3
N
4
unveiled inferior photoactivity because the LSPR phenomenon provided two pathways for electron transfer between Au NPs and g-C
3
N
4
further diminished the performance. The improved degradation lies crucially on the particle size and Schottky barrier formation at the interface of M/g-C
3
N
4
(M=Au, Ag, and Pd) but not the visible light harvesting properties. The mechanism insight revealed the holes (h
+
) and superoxide radical (
•
O
2
−
) radical actively involved in photocatalytic reaction for all composites.