1D-CoSe<sub>2</sub> nanoarray: a designed structure for efficient hydrogen evolution and symmetric supercapacitor characteristics
Iqra Rabani, Sajjad Hussain, Dhanasekaran Vikraman, Young‐Soo Seo, Jongwan Jung, Atanu Jana, Nabeen K. Shrestha, Mohammed Jalalah, Yong‐Young Noh, Supriya A. Patil
Abstract
Direct growth of self-supported one-dimensional (1D) nanorod arrays on conducting substrates is highly attractive for electrocatalysis, due to their unique shape, size, and length. In this work, a facile and simple two-step method was employed to synthesize 1D-CoSe2 nanoarrays on titanium (Ti) foil via a wet chemical ion-exchange approach. The as-synthesized 1D-CoSe2 nanoarrays were directly used as electrode materials for hydrogen evolution reaction and supercapacitors. As an electrocatalyst, the optimized 1D-CoSe2(tex-48 h) nanoarray exhibits excellent hydrogen evolution properties with a small Tafel slope of 78 mV dec-1, low overpotentials of 41 mV@1 mA cm-2 and 216 mV@10 mA cm-2, and extended robust performance for 25 h. Moreover, for a symmetric device, it delivers a maximum specific capacitance of 152 F g-1 at 0.5 A g-1 and a better energy density of 21.1 W h kg-1 at a power density of 0.5 kW kg-1. Also, the symmetric device capacity retention behavior achieves ∼96.8% of the initial result after 5000 cycles, revealing the good stability of the electrode. Our findings offer a new way to further the development of high-performance energy devices.