In Situ -Generated CO Drives Dynamic Ni–Zn Restructuring to Govern Kinetic Selectivity in CO 2 Hydrogenations

The rational design of selective, earth-abundant Ni-based catalysts for the reverse water–gas shift (RWGS) reaction is often hampered by an incomplete understanding of their operando active states. This study reveals that the CO 2 hydrogenation selectivity over Ni–Zn catalysts is governed by a support-dependent, reaction-induced dynamic restructuring, rather than by any static, preformed sites. Through a combination of in situ characterization and theoretical calculations, we demonstrate that the active Ni–Zn intermetallic core encapsulated by ZnO forms dynamically only under the RWGS atmosphere on ZrO 2 and TiO 2 supports, but not on Al 2 O 3 or during mere H 2 reduction. Crucially, we identify in situ -generated CO as the essential inducer of this reconstruction, likely via facilitating ZnO reduction. Furthermore, the product selectivity (CO vs CH 4 ) is dictated by the kinetic competition between CO desorption and its deep hydrogenation, a principle quantitatively linked to the evolved electronic structure of the active surface. This work shifts the paradigm toward designing catalysts that evolve into optimal structures in operando and provides a fundamental kinetic framework for selective CO 2 conversion.