Ni3[Fe(CN)6]2 nanocubes boost the catalytic activity of Pt for electrochemical hydrogen evolution

Abstract

Cost-effective and highly efficient electrocatalysts for hydrogen evolution reactions (HERs) are crucial and highly desired in the sustainable energy field. Despite tremendous efforts on the development of alternative catalysts, platinum (Pt) is still the most efficient catalyst for HERs. Nevertheless, it remains a great challenge to output sufficient catalytic activity with a low Pt loading. In this research, Prussian blue analogues (PBA) of nickel hexacyanoferrate (Ni₃[Fe(CN)₆]₂) nanocubes were used as the active substrate to enhance the HER activity of Pt by fabricating a Pt-Ni₃[Fe(CN)₆]₂ interface. The Ni species of Ni₃[Fe(CN)₆]₂ play key roles in contributing to the water dissociation and improving the HER kinetics, as well as helping to maintain the catalytic activity of Pt during a long-term durability test in both acidic and alkaline media. As a result, the new Ni₃[Fe(CN)₆]₂/Pt hybrid catalyst exhibits a superior catalytic property for HERs in both sulfuric acid (H₂SO₄) and potassium hydroxide with a low Pt loading of only 4.0%. Impressively, a low overpotential of 59 mV is achieved at current density of 10 mA cm⁻² in H₂SO₄, and a high mass current density of 3.75 mA μg Pt⁻¹ is obtained at an overpotential of 70 mV, which outperforms currently reported Pt-based catalysts in acid electrolyte. It is believed that this work will inspire the design of PBA-based hybrid nanomaterials with improved or new functionalities for energy conversion and catalysis applications.