# Protein-Enhanced Photoelectrochemical Sensor for Antioxidant Detection in Biodiesel Using Zinc Vanadate and Sulfur-Doped Graphitic Carbon Nitride

## TL;DR

A new sensor using proteins and special materials detects antioxidants in biodiesel, improving fuel quality and engine performance.

## Contribution

A novel protein-enhanced photoelectrochemical sensor for efficient antioxidant detection in biodiesel is introduced.

## Key findings

- The sensor showed two linear detection ranges for DBD antioxidant: 0.6 to 160 and 160 to 2000 μmol L–1.
- The sensor achieved recovery values between 98.99 and 105.26% in biodiesel samples, indicating high accuracy.
- Cytochrome C enhanced photocurrent generation by reducing charge recombination on the sensor surface.

## Abstract

Biodiesel stability is vital for performance, storage,
and environmental
benefits. However, oxidation and degradation can reduce its quality,
leading to engine issues and reduced efficiency. Antioxidants are
crucial to prevent these problems, but their detection remains a challenge.
This study introduces a photoelectrochemical (PEC) sensor for detecting
the 2-(1,1-dimethylethyl)-1,4-benzenediol (DBD) antioxidant in biodiesel.
The sensor, constructed with FTO electrodes modified with sulfur-doped
graphitic carbon nitride (g-C3N4–S),
zinc vanadate (Zn3V2O8), and the
protein cytochrome C (Cyt-c), showed a significantly higher PEC response
compared to individual materials. Cyt-c enhances the photocurrent
generation by reducing the recombination of photogenerated charges
on the PEC platform surface. Photocurrent measurements were performed
using amperometry with a 36 W white LED lamp as the irradiation source.
Under optimized conditions, the sensor demonstrated two linear detection
ranges: 0.6 to 160 and 160 to 2000 μmol L–1. The sensor was successfully applied to biodiesel samples, achieving
recovery values between 98.99 and 105.26%, highlighting its accuracy
and reliability for practical applications. This innovative approach
addresses the challenges of detecting antioxidants in biodiesel, offering
a sophisticated yet highly efficient solution to ensure fuel quality.