Controlled Synthesis of Hollow Bimetallic Prussian Blue Analog for Conversion into Efficient Oxygen Evolution Electrocatalyst

Constructing hollow coordination polymers such as metal-organic frameworks, and Prussian blue analogs (PBAs) to fulfill diverse applications still remains a great challenge and requires extensive investigations. Here, we report a straightforward one-step strategy to construct hollow bimetallic CoFe-PBA. The morphology evolution process is carefully investigated as a function of aging time and relative reactant ratio, proving that the Co 2+ -to-[Fe(CN) 6 ] 3– (Co/Fe) ratio is crucial for obtaining the hollow structure, which is revealed as an orientated dissolution–recrystallization process driven by supersaturation. The hollow CoFe-PBA acts as an ideal precursor for the derived synthesis of ternary Co-Fe-P, which provides promising performance for the oxygen evolution reaction, with a low η 10 = 235 mV vs reversible hydrogen electrode and a Tafel slope of 34 mV dec –1 . This study proposes a new method for the design and construction of hollow PBAs for further conversion into highly efficient catalyst materials.