Regulating Pt electronic properties on NiFe layered double hydroxide interface for highly efficient alkaline water splitting

Developing cost-effective and highly efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) electrocatalysts is imperative for catalyzing water electrolysis. In this study, significant change in Pt electronic properties was conducted on NiFe layered double hydroxide (NiFe-LDH) by simply regulating the order of boron-modification and Pt-deposition, thereby achieving two electrocatalysts of B-Pt-NiFe-LDH with major Pt0 species and Pt-B-NiFe-LDH with Pt2+ species as the main component, respectively. Interestingly, the B-Pt-NiFe-LDH electrocatalyst displays better alkaline OER performance with a smaller overpotential (208 mV) at 100 mA cm-2 than Pt-B-NiFe-LDH (229 mV), while the Pt-B-NiFe-LDH electrocatalyst shows superior alkaline HER performance with only 19 mV overpotential at 10 mA cm-2 compared with that of B-Pt-NiFe-LDH (65 mV) and Pt-NiFe-LDH (28 mV). The corresponding electrolyzer of B-Pt-NiFe-LDH//Pt-B-NiFe-LDH in 1 M KOH requires only a very low voltage of 1.475 V to deliver 10 mA cm-2 with good durability (110 h), which exceeds the performance of the widely studied RuO2//Pt/C cell (1.516 V). Density functional theory (DFT) calculations suggest that the Pt0 species on NiFe-LDH can lower the energy barrier for OER, while the Pt2+/4+ components are beneficial for HER. This work demonstrates the rational strategy to regulate electronic properties on electrocatalysts for highly efficient water-splitting.