2D Mo2AlB2 transition-metal-aluminum-boride-phase-integrated TiO2 nanoparticles enable accelerated carbendazim photodegradation: impact of ohmic junctions and electric fields

Abstract

In the quest for highly efficient nanomaterials to overcome the inherent challenges associated with fungicide elimination from water, herein, a novel ohmic junction was engineered by integrating layered 2D Mo₂AlB₂ with TiO₂ nanoparticles using ultrasound self-assembly technique. A comprehensive array of characterization methods was employed to probe the photophysical properties of the optimized composite (TO/15-MAB). The innovative design of the ohmic junction, facilitated by its internal electric field, significantly reduced the surface charge in the TO/15-MAB composite by transferring free electrons from Mo₂AlB₂ to TiO₂. This charge reduction enhanced the ability of the composite to attract carbendazim because of their opposing charges, promoting its swift adsorption under neutral pH conditions. Upon light irradiation, the junction accelerated the seamless transition of electrons from TiO₂ to Mo₂AlB₂ over a curved energy band, reducing the recombination of photogenerated electrons and holes and converting them into ˙O₂⁻ and ˙OH. This culminated in the rapid degradation of 15 ppm carbendazim to ∼1 ppm with an efficiency of 93.4% and an enhanced rate of k = 0.0415 min⁻¹, which is 4 times higher than that of bare TiO₂. This assertion was supported by combined experimental and theoretical evaluation. This work showcases the excellent potential of MAB phase materials in harnessing ohmic junctions and electric fields for enhanced photocatalysis, paving the way for a highly efficient and sustainable approach to eliminating fungicides from water.