Electrostatic Self-Assembly Synthesis of Pd/In₂O₃ Nanocatalysts with Improved Performance Toward CO₂ Hydrogenation to...

CO₂ hydrogenation to methanol has emerged as a promising strategy for achieving carbon neutrality and mitigating global warming, in which the supported Pd/In₂O₃ catalysts are attracting great attention due to their high selectivity. Nonetheless, conventional impregnation methods induce strong metal-support interaction (SMSI) between Pd and In₂O₃, which leads to the excessive reduction of In₂O₃ and the formation of undesirable PdIn alloy in hydrogen-rich atmospheres. Herein, we innovatively synthesized Pd/In₂O₃ nanocatalysts by the electrostatic self-assembly process between surface-modified composite precursors with opposite charges. And the organic ligands concurrently serve as Pd nanoparticle protective agents. The resultant Pd/In₂O₃ nanocatalyst demonstrates the homogeneous distribution of Pd nanoparticles with controllable sizes on In₂O₃ supports and the limited formation of PdIn alloy. As a result, it exhibits superior selectivity and stability compared to the counterparts synthesized by the conventional impregnation procedure. Typically, it attains a maximum methanol space-time yield of 0.54 g_MeOH h^-1g_cat ^-1 (300 °C, 3.5 MPa, 21,000 mL g_cat ^-1 h^-1). Notably, the correlation characterization results reveal the significant effect of small-size, highly dispersed Pd nanoparticles in mitigating MSI. These results provide an alternative strategy for synthesizing highly efficient Pd/In₂O₃ catalysts and offer a new insight into the strong metal-support interaction.