Electron trap engineering in g-C₃N₄ with molecular Mo₃S₄ clusters for visible-light-driven photocatalysis

Author(s)

Rodrigues, Mayra Luiza Goncalves ; Mateu-Campos, Juanjo ; Silva, Anelisse Brunca ; Gutierrez-Blanco, Maria ; Gabriel Filho, Jose Balena ; Ribeiro, Caue ; Llusar, Rosa ; Andres, Juan ; Longo, Elson ; Assis, Marcelo

• Document type: Journal article
• Source: JOURNAL OF MATERIALS CHEMISTRY A; v. N/A, p. 16-pg., 2025-11-12.

Abstract

In this study, a hybrid photocatalyst based on carbon nitride (g-C3N4) modified with the molecular cluster [Mo3S4Cl3(en)3]Cl was developed and evaluated for the visible-light-driven degradation of ciprofloxacin (CIP). The incorporation of the cluster introduced structural and electronic modifications in g-C3N4, as demonstrated by spectroscopic, microscopic, and electrochemical analyses. Transient photocurrent responses and Mott-Schottky plots revealed enhanced charge separation and a positive shift in flat-band potential, consistent with increased electron mobility. Impedance spectroscopy indicated reduced charge-transfer resistance, supporting more efficient carrier transport. The optimized sample containing 2.5 wt% cluster achieved complete degradation of CIP in 150 minutes and 65% mineralization under visible light. Kinetic modeling showed pseudo-first-order behavior with a 12-fold increase in the rate constant compared to pristine g-C3N4. The material maintained high performance under different pH conditions, catalyst dosages, and real water samples, including tap and river water. Interference studies with common ions revealed moderate inhibition, highlighting the importance of matrix composition. Fluorescence and absorbance-based tests identified hydroxyl radicals and singlet oxygen as the main reactive oxygen species (ROS). A mechanism is proposed in which the Mo3S4 cluster acts as an electron trap within the g-C3N4 matrix, facilitating charge separation and boosting ROS generation under visible light. The hybrid catalyst also exhibited good recyclability, maintaining over 50% of its mineralization capacity after five cycles. These results demonstrate the relevance of electron trap engineering in molecular-semiconductor hybrids for the efficient and robust photodegradation of emerging contaminants under environmentally realistic conditions. (AU)

• FAPESP's process: 23/08525-7 - Development of 3D marine collagen-based wound dressings enriched with functional nanoparticles for the regeneration of cutaneous wounds.
• Grantee: Marcelo de Assis
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 23/10329-1 - Production of value-added organic compounds (C2+) through the dry electrochemical reform of CH4 in supercritical CO2.
• Grantee: José Balena Gabriel Filho
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 24/23525-6 - DECOUPLED ELECTROCHEMICAL SYSTEMS FOR SUSTAINABLE AMMONIA ELECTROSYNTHESIS IN APROTIC MEDIA
• Grantee: Anelisse Brunca da Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 22/09717-4 - Photocatalysis of organic pollutants using g-C3N4/CoMoO4 composites
• Grantee: Mayra Luiza Gonçalves Rodrigues
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 23/02367-0 - Modification of g-C3N4 with a femtosecond laser to develop new catalysts
• Grantee: Mayra Luiza Gonçalves Rodrigues
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC