ZnO/Zn/Amorphous Carbon Matrix Nanostructured Composite Powder: a New Photocatalyst for Dye

Abstract

Both synthesis and photocatalytic potential of an innovative catalyst-powder type composite material based on the Zn or/and ZnO dispersed in a matrix of amorphous-carbon have been investigated. Zn/ZnO/amorphous-carbon nanostructured-matrix composite was prepared by partial pyrolysis method based on the Pechini method. The amorphous character of composite was characterized X-ray diffraction, while chemical bond investigated by infrared spectroscopy. The photocatalytic activity directed to the degradation of the phenol red dye of small fraction of commercial ZnO, Zn/C and Zn/ZnO/C composites were evaluated as a function of the degradation reaction of the phenol red dye, in the alkaline medium pH = 9. A mass concentration of 1:10,000 was selected being considered 30 and 150 min of reaction A comparison between photocatalytic activity showed that the degradation rate of phenol red dye is more efficient at both ZnO/Zn/C and Zn/C amorphous composites when compared to the pristine ZnO. The efficiency obeys the following order C/Zn ≥ C/ZnO/Zn > commercial ZnO with conversion equal to 70% for C/Zn and C/ZnO/Zn, while for the ZnO is around 55%. The kinetic of degradation is discussed.

Hybrid Material Based on an Amorphous-Carbon Matrix and ZnO/Zn for the Solar Photocatalytic Degradation of Basic Blue 41

“…Thus, improvement of the performance of photocatalysts is required for the treatment of polluted water. In this sense, ZnO has received increasing attention for the photocatalytic remediation of polluted water [18][19][20][21]27,28]. ZnO is a n-type semiconductor material with a high thermal conductivity, wide band gap (3.37 eV), that is able to generate charge carriers when stimulated with UVA light, biocompatible, and with a high natural abundance, and low-cost.…”

“…However, it has been reported [29,30] that ZnO is lixiviated in aqueous phase reactions even without UV-irradiation. The inhibition process of lixiviation of ZnO under UV-visible irradiation has been reported for carbon-based materials [18,27,28] and carbon quantum dots as dopants [31]. In major part, this effect occurs due to the high reduction potential of carbon materials [32][33][34][35], which allows an efficient electron-donor transference from the graphene-based layers to the semiconductor, protecting them from thermo-or photo-oxidation processes, even at strong oxidation conditions such as UV irradiation and high temperature.…”

“…In major part, this effect occurs due to the high reduction potential of carbon materials [32][33][34][35], which allows an efficient electron-donor transference from the graphene-based layers to the semiconductor, protecting them from thermo-or photo-oxidation processes, even at strong oxidation conditions such as UV irradiation and high temperature. The particle size, morphology, surface area, crystalline framework, and composition are responsible of the optoelectronic properties of ZnO [18][19][20][21][27][28][29][30][31] including the photocatalytic activity. Properties of ZnO-based materials are highly dependent of the synthesis method [18][19][20][21][27][28][29][30][31][36][37][38][39][40][41][42] including viscosity of slurry suspensions [18,20,27], Pechini synthesis [28,42], polymeric precursor degradation [29], sol-gel following annealing [19], microwave-assisted solvothermal synthesis [31], high-energy ball-milling [36], spray pyrolysis [37], suction casting [39], and hydrothermal synthesis [21,38,…”

“…Properties of ZnO-based materials are highly dependent of the synthesis method [18][19][20][21][27][28][29][30][31][36][37][38][39][40][41][42] including viscosity of slurry suspensions [18,20,27], Pechini synthesis [28,42], polymeric precursor degradation [29], sol-gel following annealing [19], microwave-assisted solvothermal synthesis [31], high-energy ball-milling [36], spray pyrolysis [37], suction casting [39], and hydrothermal synthesis [21,38,40,41], among others. These set of works have shown that ZnO is a versatile ceramic material, which can be used in several applications such as solar cells [31], varistors [36], luminescent materials [37], and photocatalysts [18][19][20][21]27,28]. An interesting approach is to combine ZnO with carbon-based materials [18,20,27,28,40,…”

“…These set of works have shown that ZnO is a versatile ceramic material, which can be used in several applications such as solar cells [31], varistors [36], luminescent materials [37], and photocatalysts [18][19][20][21]27,28]. An interesting approach is to combine ZnO with carbon-based materials [18,20,27,28,40,41] because these hybrid composites have shown a higher stability and photocatalytic activity than that observed on neat ZnO. The basic blue 41 has been chosen as target azo-dye because is widely used in the textile industry [43,44], and due to the growing concerning about the carcinogenic and mutagenic effects of this azo-dye [44].…”