Photocatalytic transformation of organics is a promising alternative to conventional synthetic methodologies. ZnIn2S4 is active in photocatalytic redox reactions, but its performance is hindered by fast charge carrier recombination, and optimizing its properties through synthesis or modification is complicated. Herein, Zn-In-S based composites were prepared via a facile solvothermal method by varying the ratio of sulfide precursor (TAA) with a fixed Zn/ In molar ratio of 1: 2. The phase composition of the obtained materials depends on the amount of TAA. At lower ratios, composites consisting of crystalline In(OH)3 and unknown ZnxInySz phase were formed. Pure-phase ZnIn2S4 was obtained when the feed molar ratio of zinc and TAA was 1: 6 or higher. The photocatalytic oxidation of benzyl alcohol (BA) and reduction of nitrobenzene (NB) in a coupled system were applied to evaluate the activity of Zn-In-S-based composites. Under visible light irradiation, the ZnxInySz/ In (OH)3 composite (ZIS14) synthesized with a molar ratio of Zn to TAA of 1: 4 exhibited boosted and optimal performance compared to the bare ZnIn2S4 and other samples. After 5 hours of irradiation, the BA conversion and benzaldehyde (BAD) yield were 57 % and 55 %, respectively, and the NB conversion and aniline (AN) yield were 70 % and 35 %, individually, outperforming previous studies under similar experimental conditions. This work not only elucidates the photoredox process of BA and NB in one system, but also has significant implications for understanding the complex hydro/solvothermal processes involved in the fabrication of multicomponent sulfides.

Constructing hierarchical and ultrathin‐structured metal sulfides is beneficial for achieving high‐efficiency hydrogen evolution catalysts. Herein, ZnIn2S4 (ZIS) hollow nanoflowers (HNFs) composed of ultrathin nanosheets are creatively synthesized via a facile trisodium citrate‐mediated and stirring‐assisted solvothermal method. Experimental results reveal that the synergy effect of ethanol, trisodium citrate, and continuous stirring during solvothermal synthesis process play a significant role in optimizing microstructure as well as physicochemical properties of as‐prepared ZIS samples. Importantly, the fabricated ZIS HNFs with the thinnest nanosheets (2.28 nm) manifest the highest average photocatalytic hydrogen generation rate of 301.5 μmol h−1, which is 2.3 times higher than that of the pristine ZIS microspheres composed of nanoparticles with Pt as the cocatalyst and triethanolamine (TEOA) as the sacrificial agent and outperforms most reported ZnIn2S4‐based materials under similar testing conditions. Moreover, the optimized sample also shows a hydrogen generation rate of 0.53 μmol h−1.in pure water without any cocatalyst. This controllable agitation of the reaction mixture during the hydro/solvothermal synthesis process offers an eco‐friendly and scalable approach for tuning the microstructure of nanomaterials with enhanced performance for various applications.

Ordered titanium dioxide nanotube arrays fabricated via electrochemical route are considered as a promising material for photocatalytic applications. Due to their amorphous character, a subsequent crystallization step is usually required. In this work, well-aligned nanotube arrays were annealed under flowing gas streams of different compositions (air/steam, air, N-2/steam, N-2, and O-2/steam) in a temperature range from 140 to 543 degrees C. Under continuous gas flow, the morphology of the crystallized titanium dioxide is strongly affected by the gas atmosphere. When using a dry gas for annealing, the tube structure was almost destroyed after 1 h treatment at 473 degrees C. In contrast, when annealing the titania nanotube array in a water vapor/gas stream, the tube morphology can be maintained up to 543 degrees C and 10 h annealing time. Moreover, nanotube arrays crystallized in a flowing gas atmosphere containing water vapor showed a significantly higher photocatalytic activity for phenol degradation under UV irradiation than nanotube arrays crystallized in a dry gas stream. Reasons for this behavior might be the preservation of the tubular structure as well as a lower concentration or density of structural defects in presence of water vapor which leads to an enhanced generation of reactive oxygen species when the arrays are exposed to UV-light.

The surface modification of commercial TiO2 Hombikat (TiO2) using nanoparticles of fullerene C60 with tetrahydrofuran (THF-nC60), as well as fullerenol C60(OH)24 nanoparticles (FNP) was investigated in this study. Characterization of THF-nC60, FNP, TiO2, TiO2/THF-nC60, and TiO2/FNP was studied by using DES, ELS, TEM, SEM, DRS and BET measurements and their photoactivity has been examined on the mesotrione degradation under simulated sunlight. It was found that FNP in self-assembled nanocomposite TiO2/FNP increased negatively charge, as well as catalytic surface of TiO2. In addition, TiO2/FNP exhibits a shift of band gap energy to lower values compared to TiO2 and TiO2/THF-nC60. BET surface area has not showed significant differences among catalysts. Furthermore, it was found that the highest photoactivity was obtained for TiO2/FNP system. Besides, influence of different concentrations of electron acceptors (H2O2 and KBrO3), as well as scavengers on the kinetics of mesotrione removal in aqueous solution with/without TiO2 and FNP under simulated sunlight was investigated. Namely, addition of mentioned electron acceptors has resulted in higher mesotrione degradation efficiency compared to O2 alone. Besides, in the first period substrate degradation probably takes place via hydroxyl radicals and after 60 min of irradiation the reaction mechanism proceeds mainly via holes. The most efficient system for mesotrione degradation and mineralization were TiO2/7 mM KBrO3 and TiO2/7 mM KBrO3/40 μl FNP, respectively.