Cyanogen Vacancies Mediated High-Entropy Prussian Blue Analogues Confined via Metastable Pyrolysis Strategy to Accelerate Electron Transfer Kinetics for Efficient Energy Conversion

Abstract

Accelerating the intrinsic electron transport and optimizing the electronic structure of the active sites in carbon-based catalysts are key challenges. This study proposes a metastable pyrolysis strategy that disrupts the local coordination environment of high-entropy Prussian blue analogue (HE-PBA) nanocubes, enabling the controlled introduction of cyanogen vacancies (V_CN) into the carbon substrate. The high-entropy effect induces multichannel electronic redistribution, and V_CN creates unsaturated coordination sites. The integration high-entropy strategies with vacancy engineering synergistically regulates the electronic structure, accelerates intrinsic electron transport and increases the availability of active sites within the HE-PBA framework. The V_CN-mediated HE-PBA exhibits an overpotential of 104 mV at 10 mA cm^-2 during the hydrogen evolution reaction (HER), with a Tafel slope of 59 mV dec^-1. Photovoltaics with HE-PBA electrodes mediated by V_CN achieve power conversion efficiencies of 8.98% and 6.24% in the iodide reduction reaction and copper reduction reaction, respectively. This study provides new insights into vacancy engineering in high-entropy catalysts and offers viable strategies for designing multifunctional and highly efficient energy conversion systems.