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 CO 2 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 CO 2 binding, and its nanopetals enabled the well dispersion of Y 2 O 3 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 CO 2 activation to CO 2 •− . Moreover, the in situ formed coupling interlayer provided a fast charge transfer channel between Y 2 O 3 and the MOF framework, which facilitated the interfacial electron migration for intermediate generation and subsequent CO 2 conversion. By regulating the contents of Cu and Y 2 O 3 within the nanocomposites, the affinity toward CO 2 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 H 2 /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 CO 2 into valuable chemicals and the design of viable catalysts for ionizing radiation. Graphical abstract