Heterogenous Fe2P-NiFe layered double hydroxide nanostructures for boosting oxygen evolution reaction

One effective approach to improve the slow kinetics of oxygen evolution reaction (OER) for water splitting is to develop high-performance electrocatalysts . The Fe 2 P-NiFe LDH/NF catalyst with hetero-interfaces in this work was created using an easy two-step process that involved electrodeposition and hydrothermal processes. In the alkaline electrolyte , the as-prepared Fe 2 P-NiFe LDH/NF demonstrates improved OER performance. The Fe 2 P-NiFe LDH/NF catalyst only requires a low overpotential of 200 mV to achieve 10 mA cm −2 , indicating the high efficiency for electrochemical reactions . Additionally, the Tafel slope of the catalyst is measured to be 59 mV dec −1 . Even at a high current density of 100 mA cm −2 , the overpotential of Fe 2 P-NiFe LDH/NF is only 250 mV, which is noticeably smaller than that of NiFe LDH/NF and commercial IrO 2 /NF. In addition, the current density of Fe 2 P-NiFe LDH/NF remains stable without any degradation during a 12 h durability test. By the SEM and TEM results, it showed that Fe 2 P with a crystalline-amorphous hybrid structure is grown at the edge of NiFe LDH nanosheets . The average length of Fe 2 P-NiFe LDH nanosheet is about 600 nm, which is longer than that of NiFe LDH nanosheets (about 400 nm). This increased size provides a larger specific area. As a result, more exposed active sites and a synergistic effect at the hetero-interface between Fe 2 P and NiFe LDH were achieved, which produces a distinct decrease in charge transfer resistance and promotes catalytic performance. Moreover, density functional theory (DFT) calculations emphasize the significance of rationally designed hetero-interfaces in increasing OER activity. It is found that the Fe 2 P-NiFe LDH/NF with a hetero-interface is an efficient OER catalyst for water splitting.