Dual Z-scheme TiO₂/sugarcane bagasse biochar/MoS₂ heterojunction for enhanced visible-light photocatalysis and energy storage

Abstract

This article describes the preparation of TiO₂/MoS₂ combined with an exponentially efficient sugarcane bagasse biochar (SBB) using a simple hydrothermal method. It was practicable to efficiently establish an effective dual Z-scheme heterojunction by analyzing the band structure of the catalyst components. This resulted in an increased number of active sites, which expeditiously facilitates the separation of photo-generated species. The created ternary nanocomposite of TiO₂/SBB/MoS₂ underwent sequential characterizations. Additionally, research was done on the basic process governing the photodegradation of methylene blue dye (MB). The TiO₂/SBB/MoS₂ (T/SBB/M) ternary hybrid photocatalyst showed a much higher photocatalytic decay efficiency of 99.3% for the removal of 30 ppm methylene blue (MB) dye under visible-light irradiation in 40 min. As compared to pristine TiO₂ NPs, MoS₂ flowers, and binary TiO₂/MoS_2, which were only around 36.6 %, 50 %, and 82 %, respectively, keeping the irradiation time. The optimum dosage of T/SBB/M catalyst in this study was recorded to be 0.3 g/L with the highest K_a value (0.1193 min^-1). According to trapping experiments, •O2- and •OH species play the major part in the photo-catalytic oxidation process, while h+ species demonstrate a minimal role. Additionally, the catalyst continued to be reactive even after four reaction cycles. Furthermore, the produced composite was studied for the energy storage application of supercapacitors. The TiO₂/SBB/MoS₂ nanocomposite showed a capacitance of 656 F g^-1 at 1.0 A g^-1. Additionally, the TiO₂/SBB/MoS₂ nanocomposite electrode exhibited an impressive 93.5% capacity retention even after 5000 cycles.