Biomimetic Synthesis of Highly Reusable MoO3-based Catalysts for Fast Degradation of Dyes

Abstract

Over the recent decades, unrelenting efforts are being devoted to the sustainable design and synthesis of transitional metal oxide-based photocatalysts with controlled morphology and structural complexity to enhance their catalytic properties. In this account, we have reported the bio-fuel-assisted hydrothermal synthesis of MoO3, MoO3:NiO, and MoO3:PdO/Pd as catalysts to remove azo pollutants from an aqueous solution. Methyl orange was selected as the model dye to represent organic pollutants. This work presents a facile method for improving the visible-light-driven catalytic activity of MoO3 by introducing NiO and PdO. When MoO3:NiO and MoO3:PdO/Pd were illuminated by solar light, emitted radiation originating from oxygen vacancies of NiO and PdO synergistically participated in catalytic reactions of MoO3 giving 98% and 95 % degradation of methyl orange, respectively, in 15 min. To confirm the supporting role of NiO and PdO in the catalysis of MoO3, catalytic experiments were carried out in dark ambient conditions, with only catalysts (without stimulants). Subsequently, the degradation efficiency of MoO3:PdO, and MoO3:NiO was increased to 73% and 84% respectively, from 62 % efficiency of MoO3 suggesting that NiO and PdO greatly increased the efficiency of MoO3 in dark conditions and nearly complete removal of methyl orange by photo-induced visible light degradation. Furthermore, the photocatalysts illustrated good reusability till four runs of experiments without loss in its degradation efficiency. Therefore, the overall catalytic results of the current study are highly proposing MoO3:PdO and MoO3:NiO as excellent photocatalysts for water remediation.