Treatment of industrial wastewater is one of the biggest challenges that mankind is facing today to prevent environmental pollution and its associated adverse effects on human health. Environmentalists across the world have given a clarion call for dye degradation, wastewater treatment and their effective management in our surrounding habitats. Despite significant progress in the development of new water treatment technologies, new materials haven’t matured enough for large scale industrial applications. Hence, the development of new scalable and sustainable multifunctional materials having the potential to treat wastewater and generate energy is the need of the hour. In this direction, novel 3D-flower shaped KTaO3 (3D-F-KT) material has been synthesized using areca seed powder as a green fuel. This new material has been successfully applied for the treatment of industrial wastewater contaminated with Rose Bengal. The efficiency of the material was analysed using several parameters like catalytic loading, dye concentration, kinetic and scavenging experiments, photostability and recyclability. In addition, the material was subjected to optical studies and H2 generation, making it a highly versatile multifunctional material, exhibiting a degradation efficiency of 94% in a short span of 150 minutes and a photocatalytic H2 generation efficiency of 374 mmolg− 1 through water splitting. With an immense potential, KTaO3 presents itself as a multifunctional catalyst that can be scaled up for a variety of industrial applications ranging from wastewater treatment to energy generation and storage.