Green synthesis of novel YMnO3-doped TiO2 for enhanced visible-light- driven photocatalytic degradation of malachite green

Abstract

Recently, new methods of utilizing chemistry materials to overcome environmental issues worldwide, for instance, water purification have widely evolved since it is well-aligned with the sustainable development goals 6: clean water and sanitation. These issues have become a vital research topic for researchers in the last decade, particularly, the use of green photocatalyst due to the limitation of renewable resources. Herein, we report the modification of titanium dioxide with yttrium manganite (TiO2/YMnO3) by a novel high-speed stirring technique in n-hexane-water utilizing Annona muricata L. leaf extracts (AMLE). The YMnO3 incorporation in the presence of TiO2 was introduced to accelerate the photocatalytic performance for the degradation of malachite green in aqueous media. TiO2 modification with YMnO3 presented a drastic decline of bandgap energy from 3.34 to 2.38 eV and the highest rate constant (kapp) of 2.275 × 10-2 min-1. Surprisingly, TiO2/YMnO3 exhibited an extraordinary photodegradation efficiency of 95.34%, which was 1.9-fold higher than that of TiO2 under visible light illumination. The enhanced photocatalytic activity is ascribed to the formation of a TiO2/YMnO3 heterojunction, narrower optical band gap, excellent charge carrier separation. H+ and .O2– were the major scavenger species that play a significant role in the photodegradation of malachite green. Additionally, TiO2/YMnO3 shows outstanding stability over five cycles of photocatalytic reaction without significant loss of its effectiveness. This work presents a recent understanding of the green construction of a novel TiO2-based YMnO3 photocatalyst with excellent efficiency in the visible region for environmental technology application in water purification specifically in degrading organic dyes.