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•Successfully doped Cu into ZnO lattice to enhance its photocatalytic activity.•Cu dopant prevented recombination of photo-excited e− and h+ of the ZnO.•The Cu-ZnO exhibited excellent ...photocatalytic degradation of monocrotophos pesticide.•The optimal mole ratio of Cu/ZnO in the Cu-ZnO for degradation of monocrotophos was 3%.•The optimal pH for the photocatalytic degradation of monocrotophos was pH 7.
In the work, we successfully synthesized Cu doped ZnO materials for photocatalytic degradation of monocrotophos pesticide (MCP). The used Cu metal doped into the ZnO matrix created an intermediate band to excite electron from valence band (VB) to conduction band (CD) of the ZnO leading to increase in optical absorption, decrease in band gap as well as photocatalytic performance of the material. Hence, the synthesized photocatalyst showed intense activity for photocatalytic degradation of MCP into CO2, H2O and harmless inorganic ions even under visible radiation. We also investigated that the 3Cu-ZnO photocatalyst, which the weight ratio of Cu/ZnO was 3 wt%, showed the highest MCP degradation efficiency among these synthesized Cu-ZnO. The excess dopants tended to form CuO existing on ZnO surface. The formed CuO acted as a center for recombination of produced electrons and holes resulted in decrease in photocatalytic performance of the Cu-ZnO. Finally, we investigated that the optimal pH for the degradation of MCP by the synthesized Cu doped ZnO photocatalyst was pH 7.
In the study, we successfully decorated MnFe2O4 on BiVO4 to highly improve its photocatalytic activity for degradation of tetracycline as well as its magnetically recovery. The decoration of MnFe2O4 ...on BiVO4 led to formation of MnFe2O4/BiVO4 Z scheme heterojunction to effectively prevent the charge recombination in each material. Upon visible light, the MnFe2O4/BiVO4 heterojunction produced significant available amounts of e− and h+ existing in the conduction band of the MnFe2O4 and the valence band of the BiVO4, respectively. These produced e− on the conduction band of the MnFe2O4, which reduction potential was approximately −0.41 eV, exhibited strong reduction potential reducing oxygen to produce •O2− radicals while h+ on the valence band of the BiVO4, which oxidation potential was 2.77 eV, showed strong oxidation potential oxidizing water and hydroxyl groups to produce •OH radicals. These generated active oxygen radicals effectively degraded TC in water (~92%). The used photocatalysts were easily recovered from photocatalytic suspension using an external magnet due to high magnetically activity of the MnFe2O4, which tightly bonded with BiVO4 in the MnFe2O4/BiVO4 heterojunction. Finally, the recovered MnFe2O4/BiVO4 heterojunction was very active and stable for tetracycline degradation in long-term process.
FeO‐doped TiO2 nanoparticle photocatalysts were immobilized onto the surface of fibrous activated carbon (ACF) via a sol‐gel process. As an adsorbent and photocatalyst, FeO‐TiO2 on immobilized ACFs ...(FeO‐TiO2/ACF) greatly improved the photocatalysis rate of hydrogen production as compared with pure TiO2 and ACF‐TiO2 under UV irradiation and visible light. The addition of ACFs surface significantly reduced the photogenerated pairs of electrons‐hole recombination, thereby promoting the photocatalysis action of doped photo‐metal oxides of FeO‐TiO2. Co‐doping of FeO onto the lattice of the TiO2 approach can improve the absorption activity of visible light through photo‐metal oxide of TiO2 and further enhance hydrogen production under visible light. The photocatalytic fabrics (FeO‐TiO2/ACF) were effortlessly split out from the experimental solution for re‐utilization and exhibited high stability even after five complete regeneration cycles.
Hydrogen production and stability of catalytic materials still suffer from low efficiency due to the fast rate of recombination of electron‐holes in the photocatalytic process. Fibrous activated carbon (ACF) served as surface immobilizer to capture co‐doped FeO/TiO2 for improving the sorption of a nanocatalyst onto the porous surface. Stable FeO/TiO2 nanoparticles were immobilized on the ACF surface.
In this study, titanium (Ti) was used as an active dopant to incorporate into BiVO4 lattice using the hydrothermal method. The synthesized BiVO4 and Ti–BiVO4 with 1, 5 and 10 wt% of Ti dopants have ...been applied for photocatalytic decomposition of Tetracycline under visible light irradiation. The characterized results showed that this synthesized BiVO4 and Ti–BiVO4 materials existed in a form of spherical particles. The particle sizes of the Ti–BiVO4 were much bigger than that of the BiVO4. However, Ti dopants effectively enhanced visible light absorption, decreased band gap energy as well as prevented electron-hole recombination of the BiVO4 leading to increase in photocatalytic activities of the doped materials. The obtained results from photocatalytic experiments indicated that the 5Ti–BiVO4, whose weight ratio of Ti was 5%, was the best material for TC degradation (78.49%). Recycling tests were consecutively carried out in 4 runs to demonstrate the stability of the BiVO4 photocatalyst with 5 wt% of Ti dopant.
In this study, InVO4 was effectively hybridized with g-C3N4 to create InVO4/g-C3N4 Z-scheme heterojunction. Ag metals were also successfully decorated on the InVO4/g-C3N4 to further improve its ...photocatalytic performance for tetracycline degradation. Scavenger experiments were conducted to investigate photocatalytic degradation mechanism of the synthesized materials. The characterization and experimental results showed that InVO4 and g-C3N4 would absorb incident visible light to induce electrons to their conduction band (CB) leaving holes at their valence band (VB). Then, photo-induced electrons in the InVO4 CB would move to the g-C3N4 VB to recombine with its holes leading to preservation of photo-induced electrons at the g-C3N4 CB, which has high reduction potential, and holes in the InVO4 VB, which has high oxidation potential, for effective degradation of tetracycline. When Ag metals were decorated on InVO4/g-C3N4, plasmon resonance of Ag would effectively increase light absorption and induce electron-hole separation of the InVO4 as well as the g-C3N4. The decorated Ag also acted as charge mediator to enhance electron transfer from the InVO4 CB and the g-C3N4 VB to improve electron-hole separation or photocatalytic efficiency of the InVO4/g-C3N4. Therefore, the Ag decorated on InVO4/g-C3N4 (AIC) presented novel photocatalytic performance for degradation of tetracycline. Finally, the regenerating experiment results indicated that the AIC could be effectively regenerated after being used.
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•Successfully established InVO4/g-C3N4 Z-scheme heterojunction.•Successfully decorated Ag on InVO4/g-C3N4 to further enhance its photocatalytic activity.•The Ag decorated on InVO4/g-C3N4 showed novel photocatalytic activity for TC degradation.•The synthesized photocatalyst exhibited novel stability and regenerating ability.
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•Synthesized Ta3N5 and V–Ta3N5 successfully converted CO2 to valuable fuels.•V dopant enhanced electron–hole separation and prolonged its lifetime.•V–Ta3N5 exhibited great increases ...in light adsorption and decreases in band gap energy.•V–Ta3N5 reduced CO2 and H2O vapor to CH4, CO, O2, and H2 even under visible light.•A V/Ta ratio of 2wt.% was optimal for enhancing the photocatalytic activity of Ta3N5.
In this study, Ta3N5 and V-doped Ta3N5 (V–Ta3N5) were synthesized as catalysts for the conversion of CO2 into valuable fuels under visible light. As compared with Ta2O5, the synthesized Ta3N5 and V–Ta3N5 exhibited great increases in visible light adsorption and decreases in band gap energy. Therefore, the synthesized Ta3N5 and V–Ta3N5 photocatalytically converted CO2 into CO and CH4 even under visible light. The V dopants, which existed in the Ta3N5 lattice, could act as an intermediate band (V3d) between the valence band (N2p) and the conduction band (Ta5d) of the Ta3N5 to increase the electron–hole separation efficiency of the photocatalyst. Thus, the photocatalytic activity of V–Ta3N5 was much higher than that of Ta3N5. However, an increase in the V doping ratio led the formation of VN particles distributed on the Ta3N5 surface. The formed particles eclipsed the light reaching the photocatalyst surface, resulted in a decrease in photocatalytic activity. The optimal V doping ratio in V–Ta3N5 was found to be 2wt.%. As a result, the production rates of CH4, CO, O2, and H2 generated from the photocatalytic reduction of CO2 by 2wt.% V–Ta3N5 under visible light were 425, 236, 1003, and 56µmolg−1cath−1, respectively.
In the study, we successfully conducted vanadium doping to improve photocatalytic performance of the CuWO4 for water splitting to produce hydrogen. The doping mechanism, optimal doping ratio and ...material stability were investigated by various characterization methods and water splitting experiments. We found that the V substituted several W elements of the CuWO4 crystal. In the V–CuWO4, V dopant existed in form of the V5+, which created new energy level between the conduction band (CB) and the valence band (VB) of the CuWO4 to improve charge transfer as well as to prevent the e− and h+ recombination of the material. The substitution of W by V dopant also led the formation of Cu+ and W5+ in the CuWO4 crystal. The formation of Cu+ and W5+ in the CuWO4 crystal not only narrowed the energy band gap but also increased the CB potential of the material. Therefore, the V–CuWO4 generated significant amount of e− under visible light and the generated e− was strong enough to react with H+ to produce H2. The optimal V/W ratio for maximum improving photocatalytic performance of the CuWO4 was 6 wt%. Finally, we investigated that our prepared V–CuWO4 showed high stability during long-term water splitting process.
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•Successfully doped V into CuWO4 crystal to enhance its photocatalytic performance.•V dopant prevented recombination of photo-excited e− and h+ of the CuWO4.•V doping narrowed the band gap energy and increased the CB potential of the CuWO4.•The V–CuWO4 exhibited excellent photocatalytic water splitting for hydrogen production.•The optimal mole ratio of V/W in the V–CuWO4 for water splitting was 6%.
In the study, we doped N into TiO2 lattice to narrow its band gap energy. Then, the synthesized N doped TiO2 material was combined with AgI to form AgI/N–TiO2 (ANT) direct Z scheme materials. The ...synthesized materials were utilized for photocatalytic removal of tetracycline (TC) using visible irradiation as an excitation source. We also conducted radical scavenging experiments to determine photocatalytic degradation mechanism. We investigated that these photo-excited electrons (e−) in N–TiO2 conduction band tended to combine with the left holes (h+) in AgI valence band maintaining h+ in the valence band of the N–TiO2 and e− in the conduction band of the AgI. The remained e− and h+ have high redox potential to initiate for photocatalytic decomposition of TC. Thus, the TC degradation by the ANT materials were significant greater than those by single components (AgI or N–TiO2). We also investigated that the TC degradation by the ANT-30 material, which the AgI: N–TiO2 molar ratio was 30%, exhibited that highest degradation efficiency. Finally, the ANT photocatalyst exhibited excellent stability during TC degradation processes supporting for its promising potential application in practical systems.
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•Successfully doped V into TaON lattice to enhance its photocatalytic activity.•V dopant enhanced e−/h+ separation and prolonged the lifetime of the generated e− and h+.•The VTaON ...converted CO2 into CH4 and CO even under visible light.•The optimal V doping ratio enhancing photocatalytic activity of TaON was 1.5 wt%.
We successfully used V as dopant to enhance activity of TaON for visible light photocatalytic reduction of CO2 into valuable fuels. We investigated that the used V dopants existed in the TaON lattice and replaced several Ta elements in the lattice leading to decrease in the conduction band minimum and increase in the valence band maximum of the prepared VTaON. Hence, the band gap energy of the prepared VTaON was lower than that of prepared TaON or the prepared VTaON material could absorb significant amount of incident visible light for production of e− and h+ pairs, which participated in reactions with CO2 and H2O to generate CH4, CO, O2 and H2. We also investigated that the optimal V/Ta ratio (or optimal amount of V dopant) for maximum enhancing photocatalytic activity of TaON was 1.5 wt%. The prepared 1.5VTaON visible light photocatalytically converted CO2 with H2O to generate CH4, CO, O2 and H2 with generation rates of 673, 206, 1479 and 67 (µmol·g−1cat·h−1), respectively.
A novel iron-modified biochar (FMBC) derived from rice straw was synthesized using FeCl3 modification for efficient As(V) removal from aqueous solution. FTIR and SEM-EDX analyses were carried out to ...determine the mechanism involved in the removal process and also demonstrated that Fe had loaded successfully on the surface of modified biochar. The iron-modified biochar showed higher arsenic removal ability than the raw biochar. The iron-modified biochar showed a maximum adsorption with an initial solution pH of 5.0. Moreover, for the tested biochar, the As(V) removal kinetics data were well fitted by the pseudo-second-order model. Furthermore, the As(V) removal data upon being well fitted by the Langmuir model showed the maximal removal capacity of 28.49 mg/g. The simple preparation process and high adsorption performance suggest that the iron-modified biochar derived from rice straw could be served as an effective, inexpensive, and environmentally sustainable adsorbent to replace typical granular activated carbon (AC) for As(III) removal from aqueous solution.
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