High-index planes T-Nb2O5 using self-assembly strategy for aerobic oxidative desulfurization in fuels

Abstract High-index planes viewed as reactive facets are possessed of the high-density, low-coordination atoms, which are distributed at catalytic sites with high activity, such as steps, edges and kink sites. Herein, the orthorhombic niobium pentoxide (T-Nb2O5) is synthesized, with the elevated ratio of high-index planes, first for aerobic oxidative desulfurization (ODS) of the refractory aromatic sulfides. Through a solvent evaporation-induced self-assembly strategy, mesoporous structure Nb2O5 with three different crystal phases, amorphous, pseudo-hexagonal and orthorhombic, are prepared using the calcination method. The proportion of high-index facets increases, as raising the calcination temperature, which contributes to the faster production of the superoxide free radical (•O2–) intermediate using molecular oxygen as the green oxidant. Under optimal conditions, a 100% sulfur removal rate is obtained using 650 °C-T-Nb2O5 within 7 h, showing its excellent catalytic performance. The cycle experiments confirm the stability of the prepared 650 °C-T-Nb2O5 after 8 times regeneration process, showing a promising prospect of NbOx-based materials for ODS under mild conditions.