Yinghuan Fu

Synthesis of visible-light responsive Sn-SnO2/C photocatalyst by simple carbothermal reduction

Sn-SnO2/C photocatalysts with visible light activity have been successfully synthesized by a simple heat-treating process using SnCl4 as precursor. The Sn-SnO2 heterojunction is built by depositing of metallic Sn on crystal lattice oxygen of as-formed SnO2, which obviously increase the amount of adsorbed oxygen on the surface of catalyst. The as-synthesized catalysts display higher photocatalytic activity than SnO2 and SnO2/C for degradation of reactive brilliant blue KN-R under visible light irradiation. The enhancement of photocatalytic performance of Sn-SnO2/C can be attributed to the formation of metallic Sn on the surface of catalysts. The metallic Sn and adsorbed oxygen as the sinks of photoinduced electron and electronic scavenges, respectively, hinder the recombination of photoexcitated electron-hole pairs, sequentially enhance the photocatalytic activity. Furthermore, a possible growth mechanism of the Sn-SnO2/C photocatalysts was proposed.

Synthesis, characterization and photocatalytic activity of Cu-doped Zn/ZnO photocatalyst with carbon modification

Herein, we report the preparation of Cu-doped Zn/ZnO composites with carbon modification via a simple replacement–hydrothermal method using Zn powder and CuSO4·5H2O as raw materials. The as-synthesized composites were characterized by powder X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PL). The results showed that Cu doping promotes crystal growth of ZnO, inhibits phase transfer of metallic Zn to ZnO, enhances the optical absorption in the visible region and reduces the recombination of photogenerated electrons and holes. Interestingly, CO2 dissolved in solution was converted to carbon adhered onto the composite surface (supported by the XPS data). The abundant carbon species present on the composite surface is favorable for surface chemical reactions because it can trap or adsorb reactants which facilitate the transfer of reactants to active sites. The photocatalytic efficiency of the as-synthesized catalysts was evaluated by the degradation of anthraquinone dye (reactive brilliant blue KN-R) in solution under sunlight irradiation. The degradation results revealed that the Cu-doped Zn/ZnO composites have better photocatalytic activities than those of ZnO and Zn/ZnO. The enhancement of the photocatalytic activity of the composites can be attributed to the existence of Cu doping, the Zn/ZnO hetero-structure and covered carbon on the surface of the photocatalysts, which causes electrons to be easily excited from the valence band to the conduction band and efficient separation of electron–hole pairs, as well as quick surface reactions in doped ZnO. Furthermore, a possible growth mechanism of the Cu-doped Zn/ZnO composites with carbon modification was proposed.

Improved Photocatalytic Activity of Copper Heterostructure Composites (Cu–Cu2O–CuO/AC) Prepared by Simple Carbothermal Reduction

Cu–Cu2O–CuO/activated carbon heterostructure composites with visible-light activity have been successfully synthesized by a simple carbothermal reduction procedure using CuSO4 as a single precursor. The resultant samples were characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy measurements. The results showed that the Cu–Cu2O–CuO composites with size less than 10 nm dispersed well on the surface of activated carbon. Activated carbon played both a reducing agent and support role in the formation of Cu–Cu2O–CuO/activated carbon heterostructure composites. X-ray photoelectron spectroscopy analysis suggests that the outside of the nanoparticles is CuO and the inside of the nanoparticles is Cu metal and Cu2O. Moreover, the composition of Cu–Cu2O–CuO/activated carbon composites can be tailored by varying the Cu loading, heat-treatment temperature, and heat-treatment time. The photocatalytic activities of the catalysts were investigated by degrading reactive brilliant blue KN-R under visible-light irradiation. The Cu–Cu2O–CuO/activated carbon heterostructure composites showed excellent photocatalytic activity compared with other catalysts (pure CuO, Cu2O, Cu2O/activated carbon, CuO/activated carbon, and Cu2O–CuO/activated carbon), which is ascribed to synergistic action between the activated carbon support and photoactive copper species, and the presence of interfacial structures such as a Cu2O/CuO heterostructure, Cu/Cu2O (or CuO) Schottky barrier, and Cu2O/Cu/CuO ohmic heterojunction.

Synthesis, Characterization, and Photocatalytic Activity of N-Doped ZnO/ZnS Composites

The aim of the present study is to enhance photocatalytic performance of ZnO semiconductor by comodification with doping of nonmetal ions and coupling with another semiconductor. Therefore, we synthesized the N-doped ZnO/ZnS photocatalysts via a simple heat-treatment approach using L-cysteine as N and S source in this work. Anthraquinone dye (reactive brilliant blue KNR) is employed as the model contaminants to evaluate the photocatalytic activity of as-synthesized samples under sunlight illumination. The N-doped ZnO/ZnS synthesized by this method shows better photocatalytic activity as compared to that of pure ZnO. The enhanced photocatalytic activity of the N-doped ZnO/ZnS composites may be related to the existence of N doping, ZnS/ZnO heterostructure, and covered abundant carbon species on the photocatalyst surface, which causing high absorption efficiency of light, efficient separation of electron-hole pairs, and quick surface reaction in doped ZnO.

Study of the sulfurized (BiO)2CO3 as efficient visible-light induced photocatalyst

In this study, the sulfurized (BiO)2CO3 heterostructures were synthesized using a facile liquid-phase sulfurization strategy and characterized by XRD, SEM, FT-IR, XPS, UV–Vis DRS and PL techniques. It is found that sulfurization shifts slightly XRD diffraction peaks toward to lower Bragg angle, enhances significantly the optical absorption and reduces the recombination of photogenerated electrons and holes. Based on the experimental results, it is considered that novel Bi2S3/(BiO)2CO3 heterostructures with S doping (oxygen atoms substituted by sulfur) were successfully constructed. The as-obtained photocatalysts showed excellent photocatalytic activity for degradation of reactive brilliant blue (KN-R), as compared with that of pure (BiO)2CO3 under sunlight irradiation. The enhanced photocatalytic performance may be ascribed to the role of Bi2S3/(BiO)2CO3 heterostructure and S doping, which causes high absorption efficiency of light and efficient separation of photoinduced carriers in sulfurized (BiO)2CO3.

Synthesis and enhanced photoreactivity of metallic Bi-decorated BiOBr composites with abundant oxygen vacancies

Herein, a simple one-pot solvothermal strategy was put forward to obtain metal Bi-decorated BiOBr composites (Bi/BiOBr) with abundant oxygen vacancies. The metal Bi (Bi0) can be deposited into the BiOBr surface via reduction of glycerol solvent in solvothermal process. Precipitation of Bi on surface of BiOBr turned the morphologies of BiOBr from regular flower-like hierarchical architectures to scattered sheets with increase of Bi content, enhanced photoabsorption of BiOBr in whole light region. Interestingly, deposition of metallic Bi (Bi0) on the BiOBr surface could lead to formation of abundant surface oxygen vacancies. As-synthesized Bi/BiOBr composites showed better photocatalytic activity for phenol degradation under sunlight irradiation, as compared with that of BiOBr reference. The enhancement of photocatalytic activities for Bi/BiOBr composites can be attributed to the existence of Bi/BiOBr hetero-structure and abundant oxygen vacancies (as active electron trap), which causing efficient separation of electron–hole pairs in Bi/BiOBr composites.

Photoelectrocatalytic performance of conductive carbon black-modified Ti/F-PbO 2 anode for degradation of dye wastewater (reactive brilliant blue KN-R)

The conductive carbon black (CCB)-modified Ti/F-PbO2 electrodes were prepared by electrodeposition and characterized systemically using SEM, EDS, XRD, and PL. It is found that the embedding CCB into the PbO2 coating inhibited the growth and aggregation of the PbO2 crystal grains, caused the formation of porous structure and the preferred growth of the (101) and (301) planes of the PbO2 crystal, and enhanced the oxygen evolution overpotential and carrier density of PbO2. The degradation experiment of anthraquinone dye (reactive brilliant blue KN-R) showed that the CCB-modified Ti/F-PbO2 electrodes had higher photoelectrocatalytic activity than that of the bare Ti/F-PbO2 electrode. In addition, the accelerated life measurement demonstrated that the lifetime of the CCB-embedded Ti/F-PbO2 electrode was much longer than that of the bare Ti/F-PbO2 electrode. The improvement of decolorization efficiency and stability of the CCB-modified Ti/F-PbO2 can be attributed to the large active areas, the presence of photoelectric synergism, the inhibition of oxygen precipitation, high current efficiency for formation of hydroxyl radicals, and the weakening of internal stress in PbO2 coatings.

Black TiO2 nanotube arrays fabricated by electrochemical self-doping and their photoelectrochemical performance

Herein, black TiO2 nanotube arrays (NTAs) were fabricated using electrochemical self-doping approaches, and characterized systemically by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), UV-visible absorption spectroscopy and photoluminescence spectroscopy (PL). The as-obtained black TiO2 nanotube arrays (NTAs) exhibited stronger absorption in the visible-light region, a better separation rate of light-induced carriers, and higher electrical conductivity than TiO2 nanotube arrays (NTAs). These characteristics cause black TiO2 nanotube array (NTA) electrodes to have higher photoelectrocatalytic activity for degrading anthraquinone dye (reactive brilliant blue KN-R) than the TiO2 nanotube array (NTA) electrode. Furthermore, a synergetic action between photocatalysis and electrocatalysis was also observed. The black TiO2 nanotube array (NTA) electrode is considered to be a promising photoanode for the treatment of organic pollutants.

Influence of Bi2MoO6 decoration on the structure and photo-reactivity of (BiO)2CO3 photocatalyst

Abstract Bi2MoO6/(BiO)2CO3 heterojunction photocatalysts were synthesized via a facile hydrothermal route. It is found that introduced Bi2MoO6 can turn morphology of (BiO)2CO3 crystal and restrict growth of crystalline grain by changing Bi2MoO6 loadings. When Bi2MoO6 loading is lower, Bi2MoO6 can preferentially adhere on side of {001} crystal facet of (BiO)2CO3, which inhibit the growth rates in lateral orientation of {001} crystal facets and subsequently cause the preferentially growth in [001] orientation. With further increase of Bi2MoO6 loading, Bi2MoO6 nanoparticles can cover entire surface of (BiO)2CO3 crystal, which restrict largening of crystalline grain. The resulting Bi2MoO6/(BiO)2CO3 heterostructured photocatalysts exhibited higher activity for KN-R photo-degradation under artificial solar light.

Preparation of BiOBr by solvothermal routes with different solvents and their photocatalytic activity

In this paper, a series of BiOBr photocatalysts have been synthesized by solventhermal method using different solvents (water, ethanol, isobutanol, ethylene glycol, and glycerol), and were characterized by X-ray diffraction, scanning electron microscope, UV-visible diffuse reflectance spectra, and X-ray photoelectron spectroscopy. It is found that the solvent plays a key role to tune the morphology, crystal growth, and surface nature of BiOBr. The photodegradation rate of reactive brilliant blue (KN-R) over BiOBr photocatalysts prepared by water, ethanol, isobutanol, ethylene glycol, and glycerol as solvents are 52.5%, 65.0%, 54.6%, 66.1%, and 90.9%, respectively, under sunlight irradiation for 120 min. The flower-like hierarchical BiOBr prepared by glycerol as solvent exhibited better photocatalytic activity for the degradation of reactive brilliant blue (KN-R) under sunlight irradiation. The excellent photocatalytic activity of BiOBr prepared by glycerol as solvent can be attributed to its high exposed ...