Engineering the electronic structure of Ni <sub>3</sub> FeS with polyaniline for enhanced electrocatalytic performance of overall water splitting
Yang Zou, Yong-Zheng Wu, Yuan Huang, Jialin Liu, Hong Liu, Jianjun Wang
Abstract
Abstract Developing highly efficient and stable electrocatalysts for oxygen evolution reaction is of significant importance for applications in energy conversion and storage. Modulation of electronic structure of catalysts is critical for improving the performance of the resulting electrodes. Here, we report a facile way to engineer the electronic structure of Ni 3 FeS by coating a thin polyaniline (PANI) layer for improving electrocatalytic activity for overall water splitting. Experimental investigations unveil that the strong electronic interactions between the lone electron pairs of nitrogen in PANI and d orbitals of iron, nickel in Ni 3 FeS result in an electron-rich structure of Ni and Fe, and consequently optimize the adsorption and desorption processes to promote the OER activity. Remarkably, the resulting PANI/Ni 3 FeS electrode exhibited much enhanced OER performance with a low overpotential of 143 mV at a current density of 10 mA·cm −2 and good stability. Promisingly, coupled with the reported MoNi 4 /MoO 2 electrode, the two-electrode electrolyzer achieved a current density of 10 mA·cm −2 with a relatively low potential of 1.55 V, and can generate oxygen and hydrogen bubbles steadily driven by a commercial dry battery, endowed the composite electrocatalyst with high potential for practical applications.