Electrosynthesis and catalytic properties of magnesium oxide nanocrystals with porous structures

► The electrosynthesis of the precursor Mg(OH)2 nanocrystals with porous structures. ► The shape of Mg(OH)2 is greatly dependent on current density. ► The obtained MgO nanocrystals could well reserve the shapes of the precursors. ► The porous MgO nanocrystals could effectively catalyze the reaction of CO2 with propylene oxide.