Gas-dependent alloy reconstruction enables selectivity tuning in integrated CO₂ capture and hydrogenation

Understanding the dynamic phase change under operational conditions is crucial for the development of high-performance catalysts. Ni-based alloys have long been elucidated as active and selectivity-tunable phases in CO₂ hydrogenation, while their gas-dependent surface reconstruction and correlation with dynamic activities, particularly under gas-swing catalytic conditions, remain poorly understood. Herein, we demonstrate that Zn can segregate from the NiZn alloy in a CO₂ atmosphere enabling formation of well-dispersed surface Ni atoms that can gradually homogenize back into the alloy under H₂. Consequently, formation of highly stable intermediates, bridged and multi-centered carbonyls, can be effectively avoided due to the absence of closely-packed Ni sites. Instead, the linear carbonyls on Ni undergo desorption rather than further hydrogenation due to their relatively low binding energy, rendering a high CO selectivity. This insight of gas-dependent evolution of sites will enable the rational design of alloy catalysts for multi gas swing catalytic applications.