Boosting charge transfer via interface charge reconstruction between amorphous NiFe-LDH and crystalline NiCo2O4 for efficient alkaline water/seawater oxidation
Zhong-Hang Xing, Yi Zhao, Yunhai Wang, Xiaohe Liu, Zhiqiang Guo, Qing‐Yun Chen
Abstract
Electrocatalysts with optimal efficiency and durability for the oxygen evolution reaction (OER) are becoming increasingly important as the demand for alkaline water/seawater electrolysis technology grows. Herein, a novel rose-shaped NiFe-layered double hydroxide (LDH)/NiCo 2 O 4 composed of amorphous wrinkled NiFe-LDH and highly crystalline NiCo 2 O 4 was synthesized with rich heterointerfaces. Many unsaturated metal sites are generated due to significant charge reconstruction at the heterointerface between the crystalline and amorphous phases. These metal sites could trigger and provide more active sites. The density functional theory (DFT) reveals that a new charge transfer channel (Co-Fe) was formed at the heterointerface between NiFe-LDH as electron acceptor and NiCo 2 O 4 as electron donor. The new charge transfer channel boosts interfacial charge transfer and enhances catalytic efficiency. The NiFe-LDH/NiCo 2 O 4 /nickel foam (NF) drives current densities of 10 and 100 mA·cm −2 with overpotentials of 193 and 236 mV, respectively. The composite electrode demonstrates a fast turnover frequency (0.0143 s −1 ) at 1.45 V vs. RHE (RHE = reversible hydrogen electrode), which is 5.5 times greater than pure NiCo 2 O 4 , suggesting its superior intrinsic activity. Additionally, NiFe-LDH/NiCo 2 O 4 /NF electrode exhibited negligible degradation after 150 h of uninterrupted running in alkaline seawater oxidation. This study introduces a method for preparing high-efficiency electrocatalysts utilized in alkaline water/seawater electrolysis.