A magnetic MXene-porous polydopamine multi-interface catalyst for highly efficient photo-Fenton degradation of methylene blue

Conventional homogeneous catalysts for photo-Fenton reactions suffer from inherent drawbacks, including difficult recovery, poor stability, and rate-limiting steps, which significantly restrict their practical application. To overcome these challenges, a novel photo-Fenton catalytic support, MXene–porous polydopamine (MPP), was fabricated via an interfacial co-assembly strategy. Subsequently, nano zero-valent iron (Fe) was anchored onto the MPP framework to construct a magnetic MXene–porous polydopamine (Fe/MPP) catalyst. The unique multi-interfacial porous structure of Fe/MPP facilitates efficient mass and electron transport, while the synergistic effects of Fe redox cycling and phenol–quinone conversion under light irradiation enhance the Fe 3+ /Fe 2+ regeneration process. As a result, Fe/MPP achieved outstanding photo-Fenton degradation performance, removing 99.89 % of methylene blue (MB, 4 g/L) within 30 min, surpassing most previously reported homogeneous catalysts. Moreover, Fe/MPP exhibits excellent reusability, maintaining over 53 % degradation efficiency after ten consecutive cycles. These results demonstrate that Fe/MPP exhibits high photo-Fenton activity and cycling stability, showing promising potential for practical wastewater treatment applications.