In-situ electrogeneration of H₂O₂ and hydroxyl radical applied for venlafaxine degradation: A novel strategy using FeSe2-modified carbon gas diffusion electrode

Author(s):Show less -

Bimbi Junior, Fausto E. ; Junior, Oswaldo C. ; Souto, Robson S. ; Encide, Joao Pedro P. ; Baruch, Micael M. ; Felipe, Maria C. V. ; Fernandes, Larissa ; Araujo, Isabela F. ; Fernandes, Carlos H. M. ; Oliveira, Igor G. S. ; Honorio, Kathia M. ; Colombo, Renata ; Mastelaro, Valmor R. ; Barros, Willyam R. P. ; Lanza, Marcos R. V.

• Document type: Journal article
• Source: CHEMICAL ENGINEERING JOURNAL; v. 517, p. 18-pg., 2025-08-01.

Abstract

In the present work, iron diselenide (FeSe2) nanoparticles (NPs) were synthesized via the hydrothermal method and were employed as photo-electrocatalysts for oxygen reduction reaction (ORR) and organic pollutant degradation. The modification of the surface of Printex L6 carbon (PL6C) structure with FeSe2 NPs resulted in enhanced ORR activity and selectivity, leading to the efficient electrogeneration of hydrogen peroxide (H2O2) and hydroxyl radical (center dot OH). The application of the 2%FeSe2-modified PL6C with gas diffusion electrode (GDE) resulted in a 2.0-fold and 3.15-fold increase in H2O2 production in alkaline and acidic media, respectively, compared to the unmodified PL6C-GDE, under identical operating conditions. Density Functional Theory (DFT) calculations confirmed that the modification of the PL6C-GDE with FeSe2 NPs markedly enhanced O2 adsorption on the PL6C surface, reducing the Gibbs free energy from -93.47 to -202.12 kJ mol- 1. Photocatalytic H2O2 production increased by 1.25-fold in alkaline media due to the narrow bandgap of FeSe2 NPs. In acidic condition, the competitive formation of center dot OH resulted in H2O2 consumption, even in the presence of a scavenger. The 2% FeSe2-modified PL6C-GDE exhibited excellent performance when applied for the photo-electrochemical degradation of 15 mg L- 1 venlafaxine, achieving complete mineralization in both alkaline (180 min) and acidic media (120 min). This work highlights the role of FeSe2 NPs in modulating ORR pathways on the PL6C catalyst and promoting efficient electron transfer, in addition to enhancing protonation, oxygen adsorption, and formation of intermediates. These effects boost H2O2 selectivity and center dot OH generation, thus making the FeSe2-modified PL6C-GDE a highly promising photo-electrocatalyst for energy conversion and environmental remediation applications. (AU)

• FAPESP's process: 22/04053-0 - Synthesis of new heterogeneous iron-based nanocatalysts (FeSe2 and Fe3O4) for application in the degradation of psychiatric drugs via photo-electro-Fenton process
• Grantee: Fausto Eduardo Bimbi Júnior
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 25/01819-0 - Electrochemical degradation of levofloxacin, nimesulide, and sulfamethoxazole in aqueous medium: in silico studies on reaction mechanisms and ecotoxicity
• Grantee: Micael Mantovani Baruch
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 18/22022-0 - EMU granted in the 2017/10118-0 process: spectroelectrochemistry system
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 22/12895-1 - Advanced processes for the degradation of emerging pollutants: catalytic materials, electroanalytical sensors and scientific dissemination
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 23/06558-5 - Gas diffusion electrodes modified with Co and Fe NPs and biochar for the degradation of antidepressant drugs: mechanistic and technological aspects
• Grantee: Carlos Henrique Magalhães Fernandes
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 18/22210-0 - EMU granted in process 2017/10118-0: liquid chromatograph (HPLC)
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 19/06650-3 - EMU granted in the 2017/10118-0 process: potentiostat system with impedance module
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 24/11170-9 - Electrosynthesis of hydrogen peroxide using gas diffusion electrodes (GDEs) modified with nanostructured electrocatalysts and their application in the degradation of polluting organic compounds
• Grantee: Oswaldo Costa Junior
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 18/22211-7 - EMU granted in process 2017/10118-0: total organic carbon analyzer (TOC)
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Multi-user Equipment Program