Enhanced oxygen mobility of nonreducible MgO-supported Cu catalyst by defect engineering for improving the water-gas shift reaction

Understanding how to tune the properties of metal oxides is essential for developing metal oxide-supported catalysts with enhanced activity. Here, nonreducible MgO-supported Cu (MgCu) catalysts were prepared by varying the content of MgO. The rate of the water-gas shift reaction over the MgCu50 catalyst was 70 mu mol CO g(-1) s(-1) at 300 degrees C, which is twice that achieved with reported metal oxide-supported catalysts. The limited reducibility of MgO was overcome by introducing abundant defects by effectively replacing Mg2+ with Cu2+, which resulted in significant changes in the electron density of MgO. CO-pulse titration experiments proved that the defect-rich MgO-supported catalyst exhibited highly enhanced activity toward CO due to abundant active oxygen species on the surface. The reconstruction of active surface oxygen in MgO was markedly promoted in the catalysts with higher MgO content, as well as at higher temperatures. This study demonstrates the feasibility of utilizing nonreducible MgO as an active support for reactions where redox properties are important. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

Tuning the properties of metal oxides is crucial for enhancing the activity of metal oxide-supported catalysts. By introducing abundant defects into MgO, its limited reducibility can be overcome, leading to increased catalytic activity. Increasing the MgO content and temperature significantly promotes the reconstruction of active surface oxygen, demonstrating the feasibility of using nonreducible MgO as an active support for reactions where redox properties are important.