Unleashing the power of Fe2(MoO4)3 as a multifunctional material for energy storage and photocatalysis with theoretical insight from density functional theory

Abstract

In a world facing urgent environmental issues and an increasing demand for sustainable energy solutions, the quest for versatile materials that can tackle a wide range of energy challenges has become essential. This paper aims to capture the diverse capabilities of Fe2(MoO4)3, highlighting its role as a multifunctional material applicable in both photocatalysis and energy storage. A simple strategy for the synthesis of Fe2(MoO4)3 via a one-step hydrothermal route is designed to allow for multifunctional properties, such as high photocatalytic activity under visible light irradiation and excellent electrochemical behaviour for its use as the electrode in a supercapacitor.The photodegradation tests reveal that Fe2(MoO4)3 can efficiently degrade 96 % of methylene blue (MB) dye within only 70 min of exposure to visible light. The maximum Langmuir adsorption capacity of Fe2(MoO4)3 was 94.33 mg/g at 30 °C and it also followed pseudo-second order kinetic models as well. The result of thermodynamic data showed that the adsorption was spontaneous and endothermic in nature. At the same time the use of Fe2(MoO4)3 as an electrode material for supercapacitors exhibits impressive characteristics, including a high specific capacitance (472 F/g at 1 A/g), excellent cycling stability (85.4 % retention after 10,000 cycles), impressive rate capability (323 F/g even at 6 A/g), as well as noteworthy energy and power density (16 Wh/kg and 1497 W/kg). The capacitive and diffusion-controlled contribution is also investigated for Fe2(MoO4)3 using Dunn's method. First-principles Density Functional Theory simulations also support our experimental findings by demonstrating that maximum quantum capacitance can reach 580 F/g at an electrode potential of 0.65 V. All of these promising results demonstrate the multifunctionality of Fe2(MoO4)3 as a potential electrode material as well as a novel photocatalytic candidate for organic contaminant removal in water.