Revisiting magnesium oxide to boost hydrogen production via water-gas shift reaction: mechanistic study to economic evaluation

Abstract Herein, we report the use of a MgCeOx-supported Cu (MgCuCe) catalyst with a unique bead structure to augment the water-gas shift (WGS) reaction. The MgCuCe catalyst exhibited an exceptionally high reaction rate of 83 μmol g‒1 s‒1 at 300 °C, compared with that without MgO (30 μmol g‒1 s‒1). Very few studies have focused on MgO-supported catalysts owing to the reports on the inferior activity of MgO. However, this paper reports unprecedented enhancements by introducing MgO and illustrates the WGS reaction mechanism: (1) numerous defects promoted water dissociation and subsequent associative mechanism; (2) the labile oxygen in MgO participated in redox mechanisms. The hydrogen production cost realized due to the use of the MgCuCe was 0.63 USD/kg H2, which is lower than that achieved by using commercial and CeO2-supported catalysts. This study paves the way for exploiting earth-abundant MgO in developing efficient catalysts and contributes to reducing H2 production costs.