Silica improved formation of Fe(III)-S and electron-deficient effect in Fe-based catalysts to improve hydrodesulfurization

•Formation of electron-deficient Fe species in the SiO2-promoted Fe-based catalyst.•The tuning effect of SiO2 to electronic state and coordinate environment of Fe2O3.•Electron-deficient FeSx promote the formation of CUS via more Fe(III)/Fe(II)-S.•The enhanced HDS activity was mainly contributed by the enhanced DDS activity.•Cost effective and environment-friendly desulfurization catalyst design.