Computation and Investigation of Two-Dimensional WO 3 ·H 2 O Nanoflowers for Electrochemical Studies of Energy Conversion and Storage Applications.

The aim of this study is to prepare a two-dimensional (2D) WO 3 ·H 2 O nanostructure assembly into a flower shape with good chemical stability for electrochemical studies of catalyst and energy storage applications. The 2D-WO 3 ·H 2 O nanoflowers structure is created by a fast and simple process at room condition. This cost-effective and scalable technique to obtain 2D-WO 3 ·H 2 O nanoflowers illustrates two attractive applications of electrochemical capacitor with an excellent energy density value of 25.33 W h kg -1 for high power density value of 1600 W kg -1 and good hydrogen evolution reaction results (low overpotential of 290 mV at a current density of 10 mA cm -2 with a low Tafel slope of 131 mV dec -1 ). A hydrogen evolution reaction (HER) study of WO 3 in acidic media of 0.5 M H 2 SO 4 and electrochemical capacitor (supercapacitors) in 1 M Na 2 SO 4 aqueous electrolyte (three electrode system measurements) demonstrates highly desirable characteristics for practical applications. Our design for highly uniform 2D-WO 3 ·H 2 O as catalyst material for HER and active material for electrochemical capacitor studies offers an excellent foundation for design and improvement of electrochemical catalyst based on 2D-transition metal oxide materials.