Water durability modification of cerium-manganese oxide by tin shell for efficient airborne benzene oxidation

Abstract

Single or cooperative incorporation of Ce and Sn elements into α-MnO2 parent were tried to update the catalytic benzene oxidation performance, and the successive modification via Ce doping and Sn deposition was demonstrated to be a promising methodology to offer high mineralization and avoid moisture-aroused inactivation. Ce doping caused lattice distortion, increased Mn3+ content to 2.7 times that of the pristine MnO2 and weakened Mn-O bonds due to electron transfer from Ce3+ to lattice oxygen, thus facilizing oxygen vacancy formation. Further, Sn deposition on CeMn substrate induced strong metal support interaction (SMSI) due to the core-shell like structure of Sn@CeMn, which promoted the construction of active oxygen vacancies to an even larger extent (1.2 and 2.5 times that of the CeMn and pristine MnO2, respectively). The thus-formed larger amount of reactive oxygen species rendered the Sn@CeMn simultaneously with high CO2 yield and low CO production. Also benefited from the SMSI effect, the Sn@CeMn’s ability to continuously activate O2 and H2O into reactive oxygen species (e.g.,·OH radicals) was enhanced, which could offset the negativity caused by water vapor, thereby keeping > 95% removal during 5.5 h water switch on/off investigation at 200 °C. Reaction pathways were uncovered with designed experimentations.