Enhancing electrocatalytic total water splitting at few layer Pt-NiFe layered double hydroxide interfaces

Abstract

Formation of NiFe layered double hydroxide (LDH) with Pt NPs was achieved following a two-step reaction viz., the hydrothermal preparation of highly crystalline NiFe LDH sheets and the homogenous reduction of Pt4+ ions with borohydride in a solution of homogenized NiFe LDH crystalline sheets. Chemically equivalent NiFe LDH material decorated with Pt NPs was prepared by co-precipitation for comparative studies. The synthesized catalysts were systematically screened for oxygen and hydrogen evolution reactions (OER and HER) in 1M KOH. The intentional incorporation of Pt NPs on the LDH layers reduced the cell voltage and delivered high current densities with a lower loading of 0.205mgcm−2. The NiFe LDH crystalline sheets had shown significantly enhanced activity, good stability, lower overpotential (90mV) at 10mAcm−2 and lower Tafel slope (12mVdec−1) than the co-precipitated NiFe LDH in OER. Similarly, Pt NPs tethered NiFe LDH crystalline sheets showed better activity by having lower overpotential (27mV) and Tafel slope (51mVdec−1) than the co-precipitated NiFe LDH with Pt NPs. Moreover, the state-of-the-art catalysts viz., IrO2 and Pt/C 20wt% of OER and HER failed in competing with Pt NPs tethered NiFe LDH crystalline sheets.