Universal strategy for homogeneously doping noble metals into cyano-bridged coordination polymers

Coordination polymers with large surface areas and uniform but tunable cavities have attracted extensive attention because of their unique properties and potential applications in numerous fields. The introduction of noble metal into coordination polymers, which may enhance or display new behaviors beyond their parent counterparts, presents great challenges in maintaining the fragile coordination structures and meeting the compatibility. Here, cyano-bridged coordination polymers are robust and show very nice compatibilities with a series of noble metals, such as Pd, Pt, Au, Ag. Those noble elements partially take the place of the transition metal ions under room temperature (for Au and Ag) or a mild hydrothermal environment (for Pd and Pt) without damaging the framework. By using this universal simple synthetic procedure, we prepared a series of noble metal containing metal hexacyanoferrate (MHCF) with various morphologies and structures, including Pd/Pt/Ag/Au-MnHCF, Pd/Pt/Ag/Au-CoHCF, and Pd/Pt/Ag/Au-NiHCF. Among them, Pd-MnHCF demonstrates the control of morphologies by adjusting operational details, and notably, it shows very unique, enhanced catalytic performance, reflecting the superiority of cyano-connected positive-valent Pd as a single-atom catalyst.