Photocatalytic stimulation of peroxymonosulfate by novel MoO3@ZrO2 with Z-scheme heterojunction for diclofenac sodium degradation

Heterojunction of multiple semiconductors is commonly employed to improve PMS-based photocatalytic degradation of organic pollutants compared to a single-component photocatalytic system. The effect of photo-irradiation on the activation of peroxymonosulfate (PMS) utilizing MoO3@ZrO2 nanocomposite for the catalytic degradation of diclofenac sodium (DS) is investigated in this study. The effects of catalyst dosage, PMS concentration, and reaction time were investigated systemically. In the PMS/photocatalysis reaction, the Z-scheme heterojunction structure proved to be more efficient DS degradation than single-metal oxide counterparts (MoO3 and ZrO2). PMS/MoO3@ZrO2/light considerably increased the photodegradation rate, allowing the DS removal of 90.94 %. MoO3@ZrO2 nanocomposite degraded at a rate of 3.43 × 10−2 min−1 in simulated light/PMS, which is 2.88 and 6.08 times faster than ZrO2 and MoO3, respectively. Reactive species (SO4−, OH, h+, and O2−) for DS degradation were explored. The characterization results revealed that ZrO2 is coated on MoO3 nanoplates, which boosted surface adsorption sites, and decreased the bandgap of the as-prepared composites. In the PMS/MoO3@ZrO2/light system, a mechanism for catalytic degradation of DS has been postulated, and transformation intermediates generated in the process have been detected using the HPLC-TOF spectrometry approach. Additionally, MoO3@ZrO2 exhibited high stability and recycling capabilities. Mo and Zr ions leaching were found to be at considerably lower amounts after DS degradation. The fabricated MoO3@ZrO2 nanocomposite has significant promise in the further use of visible light to build novel water purification solutions due to its benefits of good catalytic activity and stability.