Electron and surface engineering of Ni₂P/MnP₄ heterojunction as high performance bifunctional electrocatalyst for...

Producing hydrogen through electrocatalytic overall water splitting with ampere-level current density is still limited by the high cost and poor stability of electrocatalysts. In this work, a new type Ni₂P/MnP₄ heterojunction composite material was designed and prepared as bifunctional electrocatalyst. Based on XPS spectra and theoretical calculation, the formation of Ni₂P/MnP₄ heterojunction successfully modulates the local electronic structure of Ni₂P and enhances the ionization of H and Ni by increasing the electron transfer rate. Moreover, the special nanovilli structure and superhydropholic/superaerophobic surface of Ni₂P/MnP₄ heterojunction accelerates the transfer of electrolyte and gaseous products. Benefiting from these advantages, the as-prepared Ni₂P/MnP₄/CF not only exhibits superior electrocatalytic performance, which can release 10 mA/cm² current density with a low overpotential of 69 mV and 247 mV for HER and OER respectively, but also shows admirable stability of continuous overall water splitting to drive 1000 mA/cm² for 180 h without notable activity degradation. We believe this material possesses outstanding potential for industrial applications, and our strategy may provide a new pathway to design relative materials.