Bifunctional Hierarchical WO3 nanorods@Br-doped g-C3N4 Z-scheme heterojunctions for efficient tetracycline photodegradation: optimization of key parameters, toxicological assessment, and electrocatalytic hydrogen evolution reaction

Sakthivel Kumaravel; Elangovan Erusappan; Shanmugam Vignesh; E Chicardi; Govindasami Periyasami; Kamakshaiah Charyulu Devarayapalli; Bolam Kim; Tae Hwan Oh; Dae Sung Lee

doi:10.1016/j.envres.2025.120793

Bifunctional Hierarchical WO₃ nanorods@Br-doped g-C₃N₄ Z-scheme heterojunctions for efficient tetracycline photodegradation: optimization of key parameters, toxicological assessment, and electrocatalytic hydrogen evolution reaction

Environ Res. 2025 Jan 8:120793. doi: 10.1016/j.envres.2025.120793. Online ahead of print.

Authors

Sakthivel Kumaravel¹, Elangovan Erusappan², Shanmugam Vignesh³, E Chicardi⁴, Govindasami Periyasami⁵, Kamakshaiah Charyulu Devarayapalli¹, Bolam Kim¹, Tae Hwan Oh⁶, Dae Sung Lee⁷

Affiliations

¹ Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea.
² Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai, Tamil Nadu 602105, India.
³ School of Chemical Engineering, Yeungnam University, Gyeongsan 38436, Republic of Korea.
⁴ Departamento de Ingeniería y Ciencia de los Materiales y del Transporte, E.T.S. de Ingenieros, Universidad de Sevilla, Avda. Camino de los Descubrimientos s/n., 41092 Sevilla, Spain.
⁵ Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia.
⁶ School of Chemical Engineering, Yeungnam University, Gyeongsan 38436, Republic of Korea. Electronic address: [email protected].
⁷ Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea. Electronic address: [email protected].

PMID: 39793873
DOI: 10.1016/j.envres.2025.120793

Abstract

In this study, graphitic carbon nitride (CN) and tungsten trioxide (WO₃) were successfully incorporated into bromine (Br)-doped graphitic carbon nitride (BCN) using an in-situ hydrothermal method. The photocatalytic efficiency of the resulting WO₃/Br-doped CN (WBCN) composites for the removal of tetracycline (TC) antibiotics under sunlight irradiation was evaluated. The mass ratio of WO₃ to Br-doped CN (BCN) significantly influenced TC adsorption and photocatalytic degradation, with an optimal ratio of 9:1. The synthesized catalyst exhibited exceptional performance, achieving 98% TC detoxification under sunlight, attributed to enhanced light absorption, efficient charge separation, and reduced electron-hole (e^-/h⁺) recombination facilitated by BCN doping. Trapping experiments and ESR analysis identified ^•O₂^- and ^•OH as the primary reactive species in TC decomposition, with h⁺ radicals playing a secondary role. Reusability tests further confirmed the high stability of the photocatalyst. The Z-scheme charge transfer mechanism was elucidated, highlighting the crucial role of Br doping in enhancing synergistic interactions between WO₃ and CN. Additionally, the nickel foam (NF) electrode supported by the WBCN-2 composite demonstrated remarkable electrocatalytic activity for hydrogen evolution, achieving a minimum overpotential of 99 mV and a Tafel slope of 108 mV/dec at a current density of 10 mA/cm². The WBCN-2@NF composite catalyst also achieved excellent performance, with a low cell voltage of 1.77 V at 10 mA/cm². Chronopotentiometry (CP) tests revealed remarkable long-term stability, with minimal current loss over 15 h of continuous operation. Overall, the WBCN composite exhibits excellent photocatalytic and electrocatalytic performance, making it a promising candidate for practical environmental remediation and sustainable energy production.

Keywords: Degradation; Hydrogen evolution reaction; Photocatalyst; Tetracycline; WO(3)/Br-g-C(3)N(4).