Solar driven semiconductor photocatalytic water splitting to produce hydrogen is an extremely charming process by storing photon energy in chemical bonds. In the present study, composite semiconductor TiO 2 /CdS was structured into uniform and porous double-shelled hollow sphere with cocatalyst platinum selectively loaded onto the internal wall. The SEM, TEM , STEM , XRD , BET and EDS elemental distribution etc. were employed to evidence the formation of the targeted photocatalyst . It was demonstrated that the material has a high efficiency of visible-light-driven hydrogen evolution (296 μmol·h −1 /10 mg) with an apparent quantum efficiency (QE) of 14.5% at wavelength of 420 nm. Comparative experiment analysis and time-resolved infrared absorption study suggested that the high photocatalytic activity of the catalyst is attributed to the vectorial electron transfer (CdS → TiO 2 → Pt) and the spatial separation of reduction and oxidation active surfaces achieved by the special morphology.
Natural mineral composite catalysts have attracted much attention due to their great potential in the fields of water treatment, air purification and energy conversion. In this study, porous TiO 2 materials were synthesized from ilmenite by a two-stage calcination and acid leaching process, and porous TiO 2 /CdS composites were prepared by a hydrothermal method. The results of photocatalytic experiments indicate that the porous TiO 2 /CdS composite (PTC-2) with a Ti/Cd molar ratio of 1:1 exhibits the highest photocatalytic activity, with the degradation rate of methylene blue achieving a maximum value of 96.6% at 80 min. Moreover, the composite maintains a degradation efficiency of 88.5% after five cycles. The findings demonstrate that the TiO 2 /CdS heterojunction significantly enhances the photocatalyst's absorption of visible light while facilitating the effective separation and transfer of photogenerated electron–hole (e − /h + ) pairs. The porous architecture of the composite facilitates superior electron transport pathways and effectively mitigates e − /h + recombination. Furthermore, a mechanism for the photocatalytic degradation of organic dyes using porous TiO 2 /CdS composites is proposed, wherein photogenerated superoxide radicals ( · O 2 − ) and hydroxyl radicals ( · OH) serve as the primary reactive species. This study explores the cost-effective synthesis of TiO 2 /CdS heterojunctions and makes a significant contribution to the advancement and utilization of natural minerals for pollution degradation.
In this work, beta zeolite supported Ti 3+ -TiO 2 /CdS heterojunction was prepared for photodegradation of tetracycline under visible-light irradiation, and zeolite served as a support for the high dispersions of the Ti 3+ -TiO 2 nanoparticles . The obtained zeolite/Ti 3+ -TiO 2 /CdS heterojunction showed a relatively high surface areas of approximately 63.2 m 2 g −1 , much higher than those of the prepared Ti 3+ -TiO 2 /CdS (27.1 m 2 g −1 ), Ti 3+ -TiO 2 (36.5 m 2 g −1 ), and CdS (31.1 m 2 g −1 ), strongly demonstrating the significant of zeolite for high dispersion of the Ti 3+ -TiO 2 /CdS composite. Besides, the experimental results also showed that the photocatalytic degradation efficiency could reach 78 % in 3 min for the zeolite/Ti 3+ -TiO 2 /CdS heterojunction, and the corresponding rate constant was as high as 0.788 min −1 , which was 26.90 times that of pristine Ti 3+ -TiO 2 , 2.24 times of pristine CdS , and 2.04 times of the Ti 3+ -TiO 2 /CdS composite, mainly because of the supporting effects of zeolite and the formation of Ti 3+ -TiO 2 /CdS heterostructure for highly enhanced charge separation. In addition, the trapping experiment revealed that the main reactive species involved in tetracycline degradation were attributed to the photo-generated holes and ⸱O 2 - species.
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