Co,N-codoped MoOx nanoclusters on graphene derived from polyoxometalate for highly efficient aerobic oxidation desulfurization of diesel

Abstract

Aerobic oxidative desulfurization (AODS) offers a sustainable and cost-effective alternative to conventional diesel desulfurization techniques. However, despite its potential, the development of catalysts with both high activity and stability remains a critical challenge in this field. Here we present the synthesis of polyoxometalate (POM) derived Co,N-codoped MoOx nanoclusters on graphene sheets for boosting the AODS reactions, which combines the characteristics of sub-nanometer size of POMs and excellent stability of metal oxides. Through experimental characterizations and density functional theory (DFT) calculations, we demonstrate that the MoOx nanoclusters can effectively activate O2 by electron transfer, while the doped Co and N elements further optimize the electronic structure of Mo sites, resulting in a significant enhancement in catalytic activity. The optimized catalyst exhibits an impressive turnover frequency of 67.88 h−1 in the oxidation of dibenzothiophene (DBT), facilitating the rapid conversion of various thiophenes under mild conditions. The catalyst also demonstrates prominent durability in seven cycles of reuse with consistent catalytic performance and unchanged chemical structure. More importantly, the catalyst achieves deep AODS of real diesel, showcasing its potential for practical applications.