Developing low-cost and visible-light-driven metal oxide and sulfide-based photocatalysts for the degradation of organic dyes has been a major area of research to mitigate environmental pollution. In this study, a low-cost and facile precipitation method at low temperature of 95 °C was used to synthesize visible-light-driven Nd 2 O 3 /Mo(S,O) 3-x ·0.34H 2 O heterojunctions (NdMoOS). The crystal structure, elemental composition, optical, and electrical properties of as-prepared materials were investigated using various analytical techniques. Organic dyes of methyl orange (MO), Rhodamine B (RhB), and Methylene blue (MB) were selected as model organic pollutants to evaluate the photocatalytic efficiency of as-synthesized materials under visible light irradiation. 20 mol% NdMoOS nanocomposite showed excellent degradation efficiency and it decomposed 98.8%, 99.9%, and 99.8% of MO, RhB, and MB after 120 min, 90 min, and 90 min visible light irradiation, respectively. HPLC-MS analysis further confirms the complete removal of dyes. The formation of heterojunction, high charge separation, and low recombination rate of photoinduced e - -h + pairs can contribute to the enhanced photocatalytic activity. Superoxide radicals (O 2–• ), hydroxyl radicals (HO • ), and holes (h + ) were identified as major oxidative species involved in the photocatalytic degradation mechanisms of MO, RhB, and MB dyes.
Xiaoyun Chen,Huizhi Sun,Dong-Hau Kuo,Adugna Boke Abdeta,Osman Ahmed Zelekew,Yuanbo Guo,Jubin Zhang,Zhanhui Yuan,Jinguo Lin
Photocatalytic H 2 O splitting by sulfide-based materials is a great challenge, because of the poor resilience of such materials against hole oxidation. Although sulfide ion of catalyst negatively shifts the valence band-edge relative to its oxide ion, the instability of sulfide ions during H 2 O oxidation is a critical obstacle to simultaneous evolution of H 2 and O 2 . Here, active, stable, and spherical nanoflower-like bimetal (Mo,Ni)(S,O) 3- x sulfo-oxide catalysts with a band gap of ∼2.1 eV and different concentrations of oxygen vacancy defects were synthesized for H 2 O splitting. (Mo,Ni)(S,O) 3- x of 25 mg with a suitable amount of oxygen vacancy defects could evolve 587.5 μmol/h H 2 under visible-light irradiation. This work demonstrated an example of converting an oxidation photocatalyst into a reduction one. Microstructure analysis showed that surface oxygen vacancy defects and the multiple-valence charges in Ni and Mo not only promoted effective separation, interface transfer, and reactions of photo-carriers but also reduced the charge build-up to avoid photo-corrosion during photocatalytic water decomposition.
危险品化学品经营许可证（带存储）