In this study, we synthesize SnO₂, rGO, La-SnO₂, SnO₂/rGO and La-SnO₂/rGO samples using a facile hydrothermal method for supercapacitor and photocatalytic applications. The synthesized SnO₂, rGO, La-SnO₂, SnO₂/rGO and La-SnO₂/rGO samples were characterized by using various analytical tools. The X-ray diffraction result confirms the rutile tetragonal structure and the average crystallite size found between 55-37 nm for the synthesized samples. The surface area was found at 106.2, 114.6 and 145.6 m²/g for La-SnO₂, SnO₂/rGO and La-SnO₂/rGO samples. The La-SnO₂@rGO sample shows lower band gap compared to La-SnO₂ and SnO₂/rGO synthesized samples. The X-ray photoelectron spectra shows the binding energy state of Sn 3d, La 3d, O 1s and C 1s peaks which reveal the presence of Sn, La, C and O species in the La-SnO₂, SnO₂/rGO and La-SnO₂/rGO samples. The fabricated asymmetric supercapacitor, La-SnO₂@rGO//Activated Carbon device offered an energy density and power density of 41.2 W h kg⁻¹ and 750 W kg⁻¹ at a current density of 1 A/g. Further, the La-SnO₂/rGO composite was used for photo-catalytic degradation of methylene blue dye under visible light irradiation. The La-SnO₂/rGO composite catalyst offered a maximum degradation efficiency of about 98% which is higher than that of any other synthesized samples. Henceforth, this study demonstrates the La-SnO₂/rGO composite is the outstanding bifunctional materials for supercapacitor and photocatalytic applications.

Key words: La-SnO₂@rGO, asymmetric supercapacitor device, photo-catalytic degradation, methylene blue.