The Rational Design of Catalyst Surfaces via Crystal Phase-Confined Enrichment

The efficient hydrogenation of CO2 to methanol and dimethyl ether (DME) is a cornerstone of the circular carbon economy, yet it is constrained by the kinetically sluggish activation of H2 on oxide catalysts. While metal–support interactions offer a lever for tuning activity, a rational strategy to precisely control the spatial distribution of active sites remains a fundamental challenge. Here, we report that the crystallinity of a common oxide support, ZrO2, can be engineered to dictate the surface enrichment of the active GaOx phase in GaOx/ZrO2 catalysts, a phenomenon we coin “crystal phase-confined surface enrichment”. Through a combination of in situ spectroscopy, kinetic analysis, and DFT calculations, we demonstrate that the tetragonal ZrO2 phase selectively suppresses the bulk migration of GaOx, thereby concentrating it on the surface. This structural feature creates a highly active interface that significantly enhances H2 activation, reducing its onset temperature by 25 K and enabling a methanol and DME selectivity of 79.5% with a CO2 conversion yield of 7.25%. Our findings establish support crystallinity engineering as a general design principle for manipulating active site distribution, propelling catalyst design from empirical tuning to predictive structure control for a wide range of heterogeneous catalytic reactions.