Environmental pollution caused by industrial waste is an increasing concern, and the design and development of efficient photocatalysts offer promising approaches to address this issue. A series of novel Zn 0.6 Cd 0.4 S/ZnO/g-C 3 N 4 composites were prepared through a calcination‒hydrothermal method. Under visible light, these materials demonstrated exceptional performance in the photodegradation of methylene blue (MB), rhodamine B (RhB), and tetracycline (TC). Among the composite materials, Z 0.6 C 0.4 S/ZnO/CN-35% exhibited the highest degradation efficiencies for MB (98.52%), RhB (99.45%), and TC (98.20%), demonstrating excellent reusability as well. The photocatalytic performance of the catalysts was assessed across various water sources and different pH conditions. The findings revealed that the degradation efficiency for contaminants in seawater, lake water, and tap water closely mirrored that observed in deionized water, suggesting wide adaptability among different aqueous solutions. The exceptional photocatalytic performance of the composite materials can be attributed primarily to the efficient separation and migration of holes (h + ) and electrons (e − ) via well-contacted interfaces. Free radical capture experiments confirmed that hydroxyl radicals (·OH) and superoxide ion radicals (·O 2 - ) play crucial roles in the reaction process. The photocatalytic mechanism was also revealed via density functional theory (DFT) calculations. This work introduced an innovative strategy to design and fabricate novel photocatalysts, emphasizing their extensive applications from both theoretical and experimental aspects.
Jianing Li,Juan Chen,Yanhui Ao,Xin Gao,Huinan Che,Peifang Wang
The construction of dual Z-scheme photocatalysts is an effective way to promote the separation and migration of electrons-holes as well as retain their high redox abilities. Herein, a distinctive dual Z-scheme photocatalyst based on phase junction WO 3 and CdS (CW) was successfully fabricated via hydrothermal method and in-situ precipitation process. The as-prepared materials showed the advantages of both phase junction and dual Z-scheme mechanism (promoted utilization of carriers and improved redox potential). As a result, the k app value of 75CW (0.05237 min −1 ) was 29.8 times that of phase junction WO 3 (0.00176 min −1 ) and 2.9 times that of CdS (0.01799 min −1 ) in terms of imidacloprid (IMD) degradation. Trapping experiment and electron spin resonance (ESR) proved the dual Z-scheme mechanism, the key to significantly improve photocatalytic degradation efficiency of WO 3 /CdS nanocomposites. Combined the analysis of liquid chromatography-mass spectrometry (LC-MS) with density functional theory (DFT) calculation, rational degradation pathways of IMD were put forward in detail. This work is excepted to provide new horizons for the construction of dual Z-scheme system with phase junction and the photodegradation of IMD.
Co 3 O 4 /Bi 4 O 7 /Bi 2 O 3 (CBB) composites were prepared, in which Co 3 O 4 was synthesized from Co-MOF as precursor. The peroxymonosulfate (PMS) activated by CBB catalyst under visible light was used to degrade tetracycline (TC). Owing to the synergistic effect of photocatalysis and PMS activation, 98.4% of TC was removed within 60 min. The optimal loading of Co 3 O 4 was determined, and the influence of PMS dosage, initial pH, and disturbing anions on the degradation effect were investigated. The “CBB + Vis + PMS” system showed good reusability, and the degradation was only reduced by 1.7% after 5 cycles. This system also had a good degradation of other five pollutants. The quenching experiment showed that holes (h + ), superoxide radicals (·O 2 − ), and singlet oxygen ( 1 O 2 ) were the main active species. The degradation products of TC were determined by liquid chromatography-mass spectrometry, and the degradation pathway was proposed. Finally, a double Z-scheme degradation mechanism was proposed in the “CBB + Vis + PMS” system. The peroxymonosulfate activated by CBB under visible light to degrade organic pollutants has widespread application prospects in environmental remediation. Graphical abstract
Developing a photocatalyst for efficient reduction of carbon dioxide (CO 2 ) is a long-term goal to address global climate change. In this work, a tube-like indium oxide@indium phosphide/cuprous oxide ( In 2 O 3 @InP/Cu 2 O) photocatalyst was prepared by annealing-phosphidation of In-Materials of Institute Lavoisier-68 (In-MIL-68) followed by electrodeposition of Cu 2 O, which was used to reduce CO 2 with water under light irradiation . Partial phosphidation of In 2 O 3 endowed In 2 O 3 @InP/Cu 2 O with strong light-harvesting ability. The In 2 O 3 @InP heterojunction combined with in situ loaded Cu 2 O provided a dual Z-scheme heterojunction for efficient electrons-holes separation. Under the synergisms of each component, the optimized In 2 O 3 @InP 60 /Cu 2 O-1 exhibited strong adsorption of CO 2 and excellent photocatalytic performance in CO 2 reduction. The yields of CO and CH 4 were 13.7 and 38.8 μmol g −1 , respectively, after 5 h simulated light illumination, higher than the corresponding yields with In 2 O 3 (CO: 7.2 μmol g −1 , CH 4 : 13.2 μmol g −1 ). This study may provide some insights into the design of specific ternary photocatalysts with dual Z-scheme charge transfer mode for CO 2 reduction.