Fuel, Vol.241, 861-869, 2019
Assembly of metallophthalocyanine-polyoxometalate hybrid for highly efficient desulfurization of organic and inorganic sulfur under aerobic conditions
Organic metallophthalocyanines (C116H80O32N42S11Co4) and inorganic polyoxometalates ((NH4)(5)H6PV8Mo4O40) were used as building blocks for fabrication of solid materials (Co-Pc/PMoV) to realize highly efficient oxidation of organic or inorganic sulfurs like oxygenases. The combination generated increasing catalytic activity by emerging their unique individual functions of redox ability and microenvironmental effect. Such synergy between POMs and metallophthalocyanines presented higher activity in aerobic oxidation desulfurization reaction with almost 100% removals for dibenzothiophene, 4,6-dimethyldibenzothiophene and benzothiophene and 97.6% for thiophene under atmospheric pressure with TOFs as 24.31, 48.89, 34.83, 23.77 h(-1), respectively. It also showed efficiency in desulfurization for real oil to give super-clean gasoline and diesel with low sulfur contents as 2.73 and 8.01 ppm at 7 h, respectively, which achieved the level of European (V) (10 ppm). Moreover, Co-Pc/PMoV could catalyze oxidation of inorganic sulfur ion S2- to SO42-, while it needed more catalyst and longer time to achieve the same oxidative level using either PMoV or Co-Pc. Further, Co-Pc/PMoV can be recycled nine times with no significant loss of performance and no leaching of active sites. These results demonstrated that the collaboration of multiple active sites in one combined unit can achieve superior high efficiency in aerobic heterogeneous catalysis.
Keywords:Polyoxometalate;Metallophthalocyanine;Assembly;Aerobic oxidation;Desulfurization;Organic or inorganic sulfur