Special Issue on New Concepts and Advances in Photocatalytic Materials for Sustainable Energy

The use of solar energy to drive the chemical and energy processes,and the chemical storage of solar energy are the key elements to move to a low-carbon economy,sustainable society and to foster energy transition.For this reason,there is a fast-growing scientific interest on this subject,which is part of the general effort for a solar-driven chemistry and energy,the chemistry of the future.To realize this

Enhanced photocatalytic performance of cementitious material with TiO_2@Ag modified fly ash micro-aggregates

A TiO2 photocatalyst is coated on the surface of a zeolite fly ash bead（ZFAB） to improve its dispersability and exposure degree in a cement system.The application of Ag particles in TiO2/ZFAB modified cementitious materials is to further enhance the photocatalytic performance.Various Ag@TiO2/ZFAB modified cementitious specimens with different Ag dosages are prepared and the characteristics and photocatalytic performance of the prepared samples are investigated.It is observed that the multi-level pore structure of ZFAB can improve the exposure degree of TiO2 in a cement system and is also useful to enhance the photocatalytic efficiency.With an increment of the amounts of Ag particles in the TiO2/ZFAB modified cementitious samples,the photocatalytic activities increased first and then decreased.The optimal Ag@TiO2/ZFAB modified cementitious sample reveals the maximum reaction rate constant for degrading benzene（9.91×10^-3 min^-1）,which is approximately 3 and 10 times higher than those of TiO2/ZFAB and TiO2 modified samples,respectively.This suggests that suitable Ag particles coupled with a ZFAB carrier could effectively enhance the photocatalytic effects and use of TiO2 in a cement system.Thus,ZFAB as a carrier could provide a potential method for a high efficiency engineering application of TiO2 in the construction field.

Hotspots of Photocatalytic Materials in 2020 Based on Big Data

Based on Cite Space software,big data bibliometrics analysis was carried out on the keywords of papers of photocatalytic materials published in 2020.Tracking the hotspots and directions can help young scholars to understand the latest progress.In the Web of Sciences,4147 related papers were searched with"photocatalytic materials"as the main topic.Cluster analysis showed that the hotspots were g-C_(3)N_(4),Mxene and metal-organic frameworks (MOF) and titanium dioxide (TiO_(2)).

Special Issue on "Photocatalytic Materials"

Summary and Scope Photocatalysis is an emerging technology that enables a wide variety of applications,including degradation of organics and dyes,antibacterial action,and fuel generation through water splitting and carbon dioxide reduction.Numerous inorganic semiconducting materials have been explored as photocatalysts,and the versatility of these materials and reactions has been expanded in recent years.This special issue is

Degradation of Formaldehyde and Benzene by TiO2 Photocatalytic Cement Based Materials

A novel photocatalytic cement based material was prepared. The distribution of TiO2 on the surface of cement was characterized by scanning electron microscope（SEM） and X-ray diffraction（XRD）, which showed the relationship of photocatalysis and presence of TiO2. TiO2 also had an impact on cement hydration, which was studied by thermal analysis. With 300 W UV illuminations, formaldehyde and benzene were degraded efficiently by the prepared photocatalytic cement based materials. 15wt% TiO2/cement showed the highest degradation efficiency and capability. The results show that formaldehyde and benzene can be degraded within 4 and 9 hours, respectively. Besides, inorganic ions can induce TiO2 agglomeration. As a result, the presence of inorganic ions in cement is unfavorable for degradation. The photocatalytic cement based materials were fabricated and the degradation efficiency of formaldehyde was measured on building roof under sunlight illumination. Formaldehyde in glass chamber can be degraded thoroughly within 10 days.

Synergistic effects of structural, crystalline, and chemical defects on the photocatalytic performance of Y-doped ZnO for carbaryl degradation

In this study,a photocatalytic material consisting of ZnO and yttrium-doped ZnO(YZO)nanoparticles was obtained via a facile precipitation conducted under ambient pressure whereby crystalline ZnO was successfully doped with yttrium.YZO had a hexagonal wurtzite polycrystalline structure with smaller crystal and grain sizes than ZnO,which in turn meant larger specific surface area and pore volume.Chemical defects were also produced,which facilitated photocatalytic activity,because such defects can act as reaction centers.The optical band gap magnitude and the diamagnetic nature of YZO were also determined.The structural,crystalline,and chemical defects of YZO synergistically enhanced the photocatalytic degradation of carbaryl;indeed,the kinetic rate constant of this reaction catalyzed by YZO was 11.17×10^(−2) min^(−1) under natural sunlight irradiation,higher than the value measured for ZnO(8.68×10^(−2) min^(−1)).Evidence thus indicates that yttrium-doping effectively modified some properties of ZnO nanoparticles so that YZO nanoparticles proved a suitable photocatalytic material for carbaryl degradation.

Preparation of ZnO/GO composite material with highly photocatalytic performance via an improved two-step method

ZnO/graphene oxide（ZnO/GO） composite material,in which ZnO nanoparticles were densely coated on the GO nanosheets,was successfully prepared by an improved two-step method and characterized by IR, XRD,TEM,and UV-vis techniques.The improved photocatalytic property of the ZnO/GO composite material,evaluated by the photocatalytic degradation of methyl orange（MO） under UV irradiation,is ascribed to the intimate contact between ZnO and GO,the enhanced adsorption of MO,the quick electron transfer from excited ZnO particles to GO sheets and the activation of MO molecules viaπ-πinteraction between MO and GO.

Fractional kinetics of photocatalytic degradation

In this paper,photocatalytic degradation processes of different materials are fitted to the first-order kinetic model,second-order kinetic model and fractional first-order kinetic model.Deterministic coefficients are calculated for the evaluation of the validity of these models.The fitting results show clearly that the degradation process can fit the fractional first-order kinetic model in a very good manner.In this way,two material parameters can be well defined.One is the degradation time,which can be used to describe the photocatalytic degradation process quantitatively.Another is the order of the derivative,which could be related to the material’s microstructure.