Mechanism in chlorine‐enhanced Pd catalyst for H 2 O 2 in situ synthesis in electro‐Fenton system

• Published in: AIChE journal Vol. 68; no. 10
• Main Authors: Lu, Linhui, Shu, Qingli, Zhang, Guiru, Zhang, Qi, Du, Ping, Zhu, Xuedong
• Format: Journal Article
• Language: English
• Published: 01-10-2022
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.17787

Palladium‐based catalysts have been widely employed in the electro‐Fenton process for
in situ
generation of H
2
O
2
. However, the process is still far from being practical on a large scale. In this work, a series of Cl
x
FePd/γ‐Al
2
O
3
/Al catalysts were prepared by a three‐step‐impregnation method. They exhibited excellent activity in H
2
O
2
in situ
synthesis and high efficiency in phenol degradation. The characterization results showed that Cl could assist in increasing the content of Pd
0
and reducing the isoelectric point of catalysts, which led to the drastic promotion in the synthesis of H
2
O
2
. Theoretical calculations further demonstrated that Cl doping could facilitate the main reaction in H
2
O
2
synthesis, as well as inhibit side reactions such as dissociation of the OO bond. Furthermore, kinetic models were proposed and fitted. A plausible reaction mechanism as well as degradation pathways were elaborated based on electron spin resonance and gas chromatography–mass spectrometry results. These findings illustrate the value of palladium‐based Cl
x
FePd/γ‐Al
2
O
3
/Al catalysts for their application in the electro‐Fenton process.