Ultra-low doping 0.1(PtMnFeCoNi)/TiO2 catalysts: Modulating the electronic states of active metal sites to enhance CO oxidation through high entropy strategy

The catalyst cost is a key factor limiting the CO purification of sintering flue gas. Here, an ultra-low-loading high-entropy catalyst was prepared by simple calcination process. By anchoring multiple active metal sites in the stable anatase TiO₂ phase, it shows efficient CO catalytic oxidation activity. The metal components (Pt, Mn, Fe, Co, Ni) were uniformly dispersed on the surface of TiO₂ in the form of high-entropy compounds and undergo strong metal and support interaction with TiO₂. The results showed that 0.1(PtMnFeCoNi)/TiO₂ achieved complete oxidation of CO at 230 °C, and its catalytic oxidation ability was significantly better than that of the corresponding monometallic and bimetallic catalysts. The high-entropy component adjusts the electronic environment between the TiO₂ support and the metal to promote the reduction of the Ti_3d band gap, enhances the electron-induced ability of the catalytic system to gas molecules (CO and O₂), and exhibits excellent resistance to SO₂ and H₂O. The work is of great significance to understand the synergistic regulation of catalyst activity by multiple metal at the atomic level and provides a strategy for effectively reducing the content of precious metals in the catalyst.