An amorphous zero-valent iron decorated by Fe3O4 significantly improves the Fenton-like reaction

Abstract

Glassy zero-valent iron (GZVI) is one of the potential Fenton-like catalysts due to its amorphous nature and high energy state, but the catalytic activity still needs to be further enhanced, especially using low-cost technology suitable for industrialization. In this paper, Fe3O4 particles were embedded into the surface of Fe91.9Si5.3B2.8 amorphous powder through a conventional low-cost ball milling technique, which endowed Fe3O4/GZVI with improved catalytic activity. GZVI attained the best surface morphology and the highest catalytic efficiency (3 times as high as pure GZVI) at a 10 % Fe3O4 addition. The Fe3O4-decorated catalysts could decompose p-nitrophenol by 97.37 % within 15 min and exhibited good stability and reusability within seven cycles. The galvanic cell formed between Fe3O4 and GZVI because their large OCP gap was responsible for the improved catalytic activity, which promoted electron transfer and •OH generation. The faster electron mobility accelerated the oxidation of Fe2+ and Fe0 and the reduction of Fe3+ on the catalyst surface with the aid of H2O2, thus promoting the pollutant degradation process. The amount and distribution of Fe3O4 particles and the bonding state between Fe3O4 and GZVI markedly influence the degradation reaction and reusability. Fe3O4/GZVI is a promising heterogeneous Fenton-like catalyst with low-cost and large-scale engineering application prospects.