Role of H2O in thermal-catalytic conversion of CO2

Converting CO 2 into high-value chemicals through thermal-catalytic conversion is an important means to achieve carbon cycling. As an inevitable by-product, the influence of H 2 O on catalyst structures and reactions cannot be ignored. This review systematically summarizes the regulatory effects of H 2 O on catalyst structures and reactions, as well as efficient catalyst design strategies. Excess H 2 O induces irreversible deactivation via nanoparticle agglomeration, oxidation, weakened metal-support interactions and carbon deposition; moderate H 2 O enhances performance by modulating surface/electronic structures and forming oxygen vacancies. H 2 O exerts concentration-dependent inhibitory and promotional effects via three core mechanisms: competitive adsorption, reaction pathway regulation, and thermodynamic modulation. Three key strategies are proposed to mitigate such inhibition: hydrophobic modification, in-situ H 2 O removal and consumption. On this basis, future research directions focus on clarifying water’s dual-effect boundary, integrating advanced characterization techniques with theoretical calculations, and developing low-cost H 2 O-tolerant catalysts, so as to lay a foundation for its industrialization in advancing carbon neutrality.