Templated Solid-State Fabrication of Quadrangled Mn–Co Mesoporous Oxides for Degradation of Methylene Blue in Water

摘要

By using soft reactive grinding route, mesoporous Mn-Co oxides were fabricated in the presence or absence of polyvinylpyrrolidone (PVP), respectively. Physicochemical properties of samples were characterized and their catalytic properties for degradation of methylene blue (MB) solution with H2O2 were evaluated. Results show that PVP-assisted Mn-Co mesoporous oxide displayed a quadrangled structure just with particle size of 4.6 nm and possessed high specific surface area of 166.8 m(2)/g. The degree of MB degradation reached 100 in 270 min over PVP-assisted Mn-Co oxide, whereas it only reached 86.6 over template-free catalyst. Excellent catalytic ability was ascribed to the increased specific surface area. Kinetics was also studied for the MB degradation over Mn-Co oxides. The activation energy was calculated to be 43.0 kJ/mol for the PVP-assisted Mn-Co oxide, higher than that of the PVP-free Mn-Co catalyst (23.4 kJ/mol). Quenching tests showed that hydroxyl radical played a dominant role in MB degradation. The current template-assisted solid-state synthetic technique is quite facile and effective to prepare other nanomaterials with improved physicochemical properties and catalytic performances.