Exsolution‐Driven Spinel Ni–Cu Bimetallic Catalysts for RWGS Reaction: Compositional Tuning for Enhanced Stability and CO Selectivity

ABSTRACT In this study, we develop exsolution‐driven spinel Ni–Cu bimetallic catalysts and systematically tune composition to enhance stability and CO selectivity for the reverse water–gas shift (RWGS) reaction. By tuning the Ni/Cu ratio, the catalytic activity, CO selectivity, and thermal stability were optimized. Among the various compositions, Ni 6 Cu 4 catalyst (Ni:Cu = 6:4) exhibited the most balanced and superior performance, achieving over 90% CO selectivity and more than 40% CO 2 conversion at 500°C, while maintaining stable operation for over 100 h. The enhanced RWGS performance originates from the complementary roles of Ni and Cu, where Ni facilitates H 2 activation, while Cu suppresses methanation by modifying the electronic structure of Ni and stabilizing CO intermediates. In situ DRIFTS measurements under RWGS conditions directly reveal the suppression of methanation‐related intermediates and the preferential stabilization of adsorbed CO species on the Ni 6 Cu 4 catalyst, providing evidence for the observed synergy effect. Physicochemical analyses, including XRD, XPS, H 2 ‐TPR, and CO 2 ‐TPD, show that the Ni 6 Cu 4 catalyst has the highest oxygen vacancy concentration, the smallest metal particle size, and the highest medium‐strength basicity. Overall, this work demonstrates that exsolution‐driven compositional tuning is a rational and effective strategy for designing thermally stable, nonprecious metal catalysts for RWGS applications.