Facile synthesis of a heterostructured lanthanum-doped SnO2 anchored with rGO for asymmetric supercapacitors and photocatalytic dye degradation

Abstract

Owing to its good redox properties, excellent electron–hole pair generation, wide band gap and outstanding chemical stability, SnO₂ has been considered as a promising bifunctional material for supercapacitors as well as photocatalysts, but its poor conductivity and low surface area limit the specific capacitance and catalytic efficiency. To enhance the functional properties of SnO₂, herein, lanthanum doped tin oxide anchored with reduced graphene oxide (La–SnO₂@rGO) heterostructures has been first employed. The properties of the synthesized materials were characterized by using various analytical tools. The maximum specific capacitance of 321 F g⁻¹ at a current density of 1 A g⁻¹ was obtained for the La–SnO₂@rGO electrode. The fabricated asymmetric supercapacitor using the La–SnO₂@rGO//activated carbon device exhibited high energy and power density of 41.2 W h kg⁻¹ and 750 W kg⁻¹ at a current density 1 A g⁻¹, respectively. Also, the device notably retained 82% specific capacitance after 10 000 charge–discharge cycles. On the other hand, the La–SnO₂@rGO heterostructure was utilized for the photocatalytic degradation of the methylene blue dye under visible light irradiation which showed a maximum degradation efficiency of 98%. This study contributes to the development of a facile strategy for the preparation of heterostructured materials suitable for the bifunctional applications of high capacitive supercapacitor electrodes and visible light dye degradation.