Manganese-doped molybdenum oxide boosts catalytic performance of electrocatalytic wet air oxidation at ambient temperature

Abstract

Mn-doping strategy was adopted to modify the structure of MoO2 for enhancing its catalytic activity towards room-temperature electrocatalytic wet air oxidation (ECWAO) reaction. A series of Mn-doped MoO2 were prepared on carbon support, and their structures were investigated to elucidate the productive effect of Mn doping on the catalytic activity of MoO2. The incorporation of MnIII/MnII into the MoO2 lattice induced the transformation from MoIV to MoV and created more oxygen vacancies. Such structural modifications promoted the electron transfer of MoO2 through the redox couples between MoVI/MoV/MoIV and MnIII/MnII, and facilitated the transformation from O2 to adsorbed oxygen species on MoO2 surface. As a result, the ECWAO catalytic activities of Mn-doped MoO2/graphite felt (MoO2/GF) outperformed the activity of MoO2/GF. Among the synthesized series, Mn0.066:MoO2/GF exhibited the highest activity with the maximum turnover frequency (TOF) promoted by 59% than the undoped MoO2/GF. Under the catalysis of Mn0.066:MoO2/GF, the ECWAO process obtains mineralization efficiencies generally above 85% in degrading typical pharmaceutics and person care products (PPCPs). These findings are anticipated to open up a new venue in the design and fabrication of highly active catalysts for air oxidation reactions by using the strategy of selective dopant-induced structure modification.