Selective Transformation of Inactive Ru Lateral Surfaces toward Highly Active TiO _x /Ru ^δ+ Interfaces for CO ₂ Methanation

Ru-based catalysts are recognized as highly promising candidates for CO 2 methanation, but the precise construction of the active center remains a significant challenge. We developed a strategy using atomic layer deposition (ALD) to selectively transform typically inactive Ru (101) lateral surfaces into TiO x /Ru δ+ interfaces. A volcano-type relationship between catalytic activity and ALD cycle numbers was established, with the optimized 30-TiO x /Ru catalyst achieving CO 2 conversion and CH 4 yield 3–9 times higher than those of the unmodified Ru catalyst at 498–573 K. Mechanistic investigations reveal that the TiO x /Ru δ+ interfaces enhance CO 2 adsorption, while the residual Ru (001) terraces are responsible for H 2 dissociation. Kinetic matching between CO 2 and H 2 activation facilitates CH 4 generation via the CO*-mediated route. This study offers a robust strategy for atomic-scale synthesis of catalysts and provides a comprehensive framework for decoding interfacial catalysis.