# S, N, P, and B-doped bio-carbons as dual catalysts for tetracycline degradation via the heterogeneous electro-Fenton process

## TL;DR

This paper explores using bio-carbon doped with heteroatoms as a dual catalyst for environmental cleanup, showing improved performance in degrading tetracycline in wastewater.

## Contribution

The novelty lies in the use of doped bio-carbon as a metal-free dual catalyst for both oxygen reduction and tetracycline degradation.

## Key findings

- Nitrogen-doped bio-carbon showed the highest oxygen reduction reaction activity with a JK value of 10.4 mA cm⁻2.
- All doped samples achieved tetracycline degradation efficiencies over 40%, with nitrogen-doped reaching up to 70%.
- The study demonstrates a cost-effective method for producing catalysts from agro-industrial waste for environmental remediation.

## Abstract

Bio-carbon (BC) derived from agro-industrial waste was doped with various heteroatoms (S, N, B, P) to evaluate its catalytic performance in the oxygen reduction reaction (ORR) and the electro-Fenton process. The materials were thoroughly characterized using techniques such as nitrogen adsorption at 77 K, carbon dioxide adsorption at −193 K, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Electrochemical performance was assessed via cyclic voltammetry (CV) and linear sweep voltammetry (LSV). All doped samples (S, N, B, P) showed improved ORR activity for hydrogen peroxide generation, with the nitrogen-doped bio-carbon (DBC-N) exhibiting the highest performance. This was attributed to its superior JK value (10.4 mA cm⁻2) and the lowest onset potential (E° onset = −0.14 V). Beyond their ORR catalytic activity, the doped samples were also tested as dual-function catalysts for the degradation of tetracycline via the heterogeneous electro-Fenton process. Notably, all samples achieved enhanced degradation efficiencies (> 40%), with the nitrogen-doped sample reaching a maximum of approximately 70%. This study highlights the potential of producing high-performance, metal-free ORR catalysts through a cost-effective, circular economy-based approach, offering promising applications in environmental remediation, particularly for efficient wastewater decontamination.