Highly CO-selective Ni–MgO–Ce_xZr_1–xO₂ catalyst for efficient low-temperature reverse water–gas shift reaction

High inertness of CO₂ hinders its usage as a cost-effective C₁ resource to produce value-added chemicals, and hence, reactive H₂ are often employed for CO₂ utilization. CO is a more reactive C₁ building block that can be produced via the reverse water–gas shift (RWGS) reaction using CO₂, but this requires a high temperature with robust catalysts that should endure the harsh endothermic conditions. Herein, Ni–MgO–Ce_xZr_1–xO₂ (NMC_xZ_1–xO) catalysts with various Ce/Zr ratios, giving different strong metal–support interaction (SMSI) among metallic components, are investigated for low-temperature RWGS reaction to achieve high CO selectivity. The control of Ce/Zr ratios affords systematic changes in the oxygen storage capacity (OSC), acidity, and basicity, affording remarkable changes in the catalytic behaviors for CO₂ conversion and CO selectivity. Among various NMC_xZ_1-xO catalysts, NMC_0.6Z_0.4O exhibited the highest resistance to change in reaction temperature, maintaining 100 % CO selectivity below 320 °C, whereas the CO₂ conversion and CH₄ selectivity of the other catalysts increased dramatically with increasing reaction temperature. The 100 % CO selectivity can be attributed to the high OSC and optimized balance of acidity and basicity of the NMC_0.6Z_0.4O catalyst, and its retention of catalytic activity owing to the SMSI among metallic components.