Efficient and durable electrocatalysts with superior
activity are
needed for the production of green hydrogen with a high yield and
low energy consumption. Electrocatalysts based on transition metal
oxides hold dominance due to their abundant natural resources, regulable
physical properties, and good adaptation to a solution. In numerous
oxide catalyst materials, ferroelectrics, possessing semiconducting
characteristics and switchable spontaneous polarization, have been
considered promising photoelectrodes for solar water splitting. However,
few investigations noted their potential as electrocatalysts. In this
study, we report an efficient electrocatalytic electrode made of a
BiFeO3/nickel foam heterostructure, which displays a smaller
overpotential and higher current density than the blank nickel foam
electrode. Moreover, when in contact with an alkaline solution, the
bond between hydroxyls and the BiFeO3 surface induces a
large area of upward self-polarization, lowering the adsorption energy
of subsequent adsorbates and facilitating oxygen and hydrogen evolution
reaction. Our work demonstrates an infrequent pathway of using functional
semiconducting materials for exploiting highly efficient electrocatalytic
electrodes.