Atomic hydrogen-mediated enhanced electrocatalytic hydrodehalogenation on Pd@MXene electrodes.

Area of Science:

• Environmental Chemistry
• Materials Science
• Catalysis

Background:

• Emerging halogenated organic pollutants (HOPs) pose environmental risks.
• Efficient degradation methods are needed to remove these persistent pollutants.
• Palladium (Pd) catalysts show promise but require improved performance.

Purpose of the Study:

• To synthesize a Pd@MXene catalyst for enhanced electrocatalytic hydrodehalogenation (ECH) of HOPs.
• To improve the dispersibility, catalytic activity, and stability of palladium.
• To investigate the ECH performance for diclofenac (DCF) and other HOPs.

Main Methods:

• Synthesis of Pd@MXene catalyst with controlled Pd nanoparticle size.
• Electrocatalytic hydrodehalogenation experiments using Pd@MX/CC electrodes.
• Degradation of diclofenac and other halogenated organic pollutants.
• Density functional theory (DFT) calculations to understand reaction mechanisms.

Main Results:

• Pd@MXene catalyst featured smaller Pd nanoparticles (3.62 ± 0.34 nm) and enhanced Pd (111) peaks.
• Pd@MX/CC electrode exhibited 2.48 times higher reaction rate constant for DCF degradation compared to Pd/CC.
• Consistent ECH performance across a wide range of DCF concentrations (5-100 mg/L) and high stability over 10 batches.
• Effective ECH of other HOPs including levofloxacin, tetrabromobisphenol A, and diatrizoate.
• DFT calculations confirmed optimized binding energies contributing to enhanced ECH efficiency.

Conclusions:

• The Pd@MXene catalyst significantly enhances electrocatalytic hydrodehalogenation efficiency for emerging halogenated organic pollutants.
• The catalyst demonstrates excellent activity, stability, and broad applicability for various pollutants.
• Optimized electronic configuration of Pd@MXene is key to improved catalytic performance.