In-situ fabrication of MoO3 nanobelts decorated with MoO2 nanoparticles and their enhanced photocatalytic performance.

Abstract Photocatalysis has been rapidly developed as a sustainable technology to decompose contaminants by using photogenerated carriers excited through light irradiation. Electrons for molybdenum trioxide (MoO 3) semiconductor with wide band gap can be easily transferred to its conduction band via dye sensitization effect under visible light. However, MoO 3 still suffers from poor photocatalytic ability for organic dyes due to the low energy level of the conduction band and the insufficient utilization of the induced electrons. In this study, molybdenum dioxide (MoO 2) nanoparticles were decorated on the surface of MoO 3 nanobelts without requiring an additional Mo source by using a simple in-situ hydrothermal method. In the reaction process, the partial MoO 3 itself was reduced to metallic MoO 2 nanoparticles, and the resulting intimate interface between MoO 2 and MoO 3 could accelerate the transfer of dye sensitization-induced electrons. The as-prepared MoO 2 /MoO 3 nanocomposites exhibited extremely enhanced visible light photocatalytic activity for decomposing rhodamine B (RhB) with the assistance of H 2 O 2. The mechanism for high-efficiency degradation was analyzed and explored by conducting theoretical calculations and designing further experiments. The high-efficiency degradation might be due to the synergistic effect caused by the well-matched energy band structure between dyes and MoO 3 , and the metallic MoO 2 nanoparticles, which can accelerate the production of hydroxyl radical (OH) from H 2 O 2. OH is a dominant reactive species for the degradation of RhB under visible light irradiation. Graphical abstract Unlabelled Image Highlights • MoO 3 nanobelts decorated with MoO 2 nanoparticles were constructed by a simple in-situ hydrothermal reduction method. • MoO 2 nanoparticles accelerated photocatalytic process, and high degradation efficiency of 90% was achieved. • Hydroxylradical (·OH) was confirmed to be a main active radical responsible for the enhanced photocatalytic performance. • A rapid transfer mechanism of dye-sensitized electrons from MoO 3 nanobelts to MoO 2 nanoparticles was proposed. [ABSTRACT FROM AUTHOR]