Assembling of yttrium-decorated bimetallic MOFs as a sensitized nanoreactor for gamma radiolytic reduction of carbon dioxide to syngas

Nuclear energy provides a competitive path for reduction of CO₂ with water, whereas the high-efficiency utilization of radiolytically produced active species for oriented transformation remains challenging. Herein, we report the assembling of yttrium-decorated bimetallic MOFs via one-step hydrothermal strategy, which can act as a sensitized nanoreactor for syngas production under γ-ray irradiation. The flower-shaped CuNi-MOF matrix with tunable metal centers exposed plentiful cooperative active sites for CO₂ binding, and its nanopetals enabled the well dispersion of Y₂O₃ nanoparticles on the surfaces. The introduction of high-Z element Y enhanced the secondary electron scattering and promoted the water radiolysis to produce more hydrated electrons (e_aq⁻), thus accelerating the initial CO₂ activation to CO₂^•−. Moreover, the in situ formed coupling interlayer provided a fast charge transfer channel between Y₂O₃ and the MOF framework, which facilitated the interfacial electron migration for intermediate generation and subsequent CO₂ conversion. By regulating the contents of Cu and Y₂O₃ within the nanocomposites, the affinity toward CO₂ and the product compositions could be modulated. As a result, the optimal 7CN-2Y catalyst achieved a high syngas evolution rate of 311.07 μmol g⁻¹ with a H₂/CO ratio of 2.7:1 at an absorbed dose of 4 kGy. The present study offered a feasible route for the efficient transformation of CO₂ into valuable chemicals and the design of viable catalysts for ionizing radiation.

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