Acid-activated layered δ-MnO2 promotes VOCs combustion

The layered δ-MnO2 nanomaterial is an inexpensive and environmentally friendly nanocatalyst for volatile organic compounds (VOCs) catalytic oxidation. However, easy agglomeration and sluggish kinetics lead to its poor catalytic activity. Herein, we develop an acid-activated method to prepare δ-MnO2 catalysts with weakened MnO bonds, enhanced specific surface area and increased active surface lattice oxygen species, which significantly enhances catalytic performance for toluene oxidation. The δ-MnO2 catalyst treated by 1 M hydrochloric acid for 3 h can completely convert toluene into CO2 and H2O at 280 °C under the GHSV of 72,000 mL g−1h−1, and it can maintain good catalytic stability for more than 50 h without obvious potential decay. Further, the acid-activated strategy can be extended to other phase structured MnO2 with varying degrees of catalytic activity enhancement. The results demonstrate that the acid-activated way has great potential in improving catalytic oxidation activity of nanocatalysts for eliminating VOCs.