Baojun Liu

Upconversion carbon quantum dots as visible light responsive component for efficient enhancement of photocatalytic performance

It finds that CQDs synthesized by hydrothermal method possess obvious upconversion properties that could transfer low energy photons to high energy photons, resulting in enhanced visible light response and utilization. Herein, carbon quantum dots (CQDs) modified TiO2 photocatylysts were successfully prepared by a facile sol-gel method. Photophysical and surficial properties of the as-prepared composite photocatalyst were investigated in details. Furthermore, photocatalytic performance was tested by degrading methylene blue (MB) under visible light irradiation. The degradation efficiency of methylene blue (MB) is as high as 90% within 120min, which is 3.6 times higher than that of pure TiO2.

Hexagonal microspindle of NH2-MIL-101(Fe) metal–organic frameworks with visible-light-induced photocatalytic activity for the degradation of toluene

This work focuses on exploring metal–organic frameworks (MOFs) for degradation of gaseous pollutants. We demonstrate that NH2-MIL-101(Fe) hexagonal micro-spindles, as a new photocatalyst, showed an improved performance for degradation of toluene under visible light irradiation. The structural and optical properties of the as-prepared NH2-MIL-101(Fe) hexagonal micro-spindles were characterized. Furthermore, the catalytic reaction mechanism has been investigated on the basis of in situ Fourier Transform infrared spectroscopy (FTIR) technology. Meanwhile, some intermediates (benzoic acid) and the final product (CO2) of the degradation of toluene were also identified.

Insight into the mechanism of photocatalytic degradation of gaseous o-dichlorobenzene over flower-type V2O5 hollow spheres

This work aims to explore the mechanism of photocatalytic degradation of gaseous 1,2-dichlorobenzene (o-DCB) over vanadium pentoxide (V2O5) hollow spheres. To this end, flower-type V2O5 hollow microspheres with diameters of about 700–800 nm were obtained with the assistance of carbon-sphere templates, and then tested in the photodegradation of o-DCB under visible light (λ > 400 nm). Due to its strong adsorption capacity and large specific surface area, the V2O5 hollow structure showed high photocatalytic activity in the degradation of gaseous o-DCB under visible light. Furthermore, the o-DCB degradation mechanism was investigated by using in situ Fourier transform infrared (FTIR) spectroscopy, and the intermediates, such as o-benzoquinone-type and organic acid species, and final products (CO2 and H2O) were also confirmed. Then, the reaction pathways over V2O5 were proposed. The outstanding performance indicated that the photocatalysts could be applied to air purification for Chlorinated Volatile Organic Compound (Cl–VOC) removal.

Self-templated formation of ZnFe2O4 double-shelled hollow microspheres for photocatalytic degradation of gaseous o-dichlorobenzene

In this work, double-shelled ZnFe2O4 hollow microspheres were fabricated by a facile self-templated solvothermal method and the interiors could be precisely modulated by varying the reaction rate during the calcination process. More importantly, the formation mechanism of hollow structures with complex interior architectures could be illustrated based on the interface layer effect of the adhesion and contraction forces. When evaluated as catalytic materials for degradation of gaseous o-dichlorobenzene, the as-synthesized double-shelled ZnFe2O4 hollow structures showed significantly enhanced photocatalytic performance because of higher surface area (126.7 m2 g−1) and more effective light absorption (multiple scattering for double-shelled architectures).

Photocatalytic degradation of gaseous toluene with multiphase TixZr1- xO2 synthesized via co-precipitation route

In the present work, the multiphase Ti(x)Zr(1-x)O2 particles containing cubic-phase ZrO2 were fabricated via co-precipitation route. The mole ratios of Ti and Zr elements were controlled by three levels: Ti/Zr=7/3 (maximum), Ti/Zr=5/5 (medium), and Ti/Zr=3/7 (minimum). The materials prepared were characterized by using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS) and photoluminescence (PL) spectra. For the maximum usage of solar power with fabricated catalysts, elimination of gaseous toluene was chosen as a model to evaluate the performances under visible light. The results indicated that the degradation efficiency of toluene was about 80% after 6 h reaction using Ti(0.3)Zr(0.7)O2 as the photocatalyst. On the other hand, the multiphase Ti(x)Zr(1-x)O2 (x=0.7 or 0.5) photocatalysts showed significant enhancement in the activity, compared with the commercial TiO2 (Degussa P25). The enhanced performances of Ti(x)Zr(1-x)O2 might be attributed to the lower charge recombination rate of photoinduced electron-hole pairs. In addition, some intermediates (the benzaldehyde and benzoic acid) and final product (CO2) adsorbed on the surface of the particles were also detected by using in situ Fourier transform infrared (FTIR) spectroscopy.

Sustainable synthesis of highly efficient sunlight-driven Ag embedded AgCl photocatalysts

Plasmonic silver embedded silver chloride (Ag@AgCl) nano-photocatalysts were synthesized in a microbe-free aqueous lysogeny broth (Miller) solution, at room temperature with 5 min sunlight exposure. The nanohybrids were formed by in situ photoreduction and photo-accelerated ripening of AgCl colloids, promoted by the attached biomolecular ligands. Compared with commercial TiO2, the biogenic Ag@AgCl nanocomposites demonstrate higher photocatalytic activity towards decomposition of organic dye solution under solar light with excellent photocatalytic stability.

CO2 Fixation, Lipid Production, and Power Generation by a Novel Air-Lift-Type Microbial Carbon Capture Cell System.

An air-lift-type microbial carbon capture cell (ALMCC) was constructed for the first time by using an air-lift-type photobioreactor as the cathode chamber. The performance of ALMCC in fixing high concentration of CO2, producing energy (power and biodiesel), and removing COD together with nutrients was investigated and compared with the traditional microbial carbon capture cell (MCC) and air-lift-type photobioreactor (ALP). The ALMCC system produced a maximum power density of 972.5 mW·m(-3) and removed 86.69% of COD, 70.52% of ammonium nitrogen, and 69.24% of phosphorus, which indicate that ALMCC performed better than MCC in terms of power generation and wastewater treatment efficiency. Besides, ALMCC demonstrated 9.98- and 1.88-fold increases over ALP and MCC in the CO2 fixation rate, respectively. Similarly, the ALMCC significantly presented a higher lipid productivity compared to those control reactors. More importantly, the preliminary analysis of energy balance suggested that the net energy of the ALMCC system was significantly superior to other systems and could theoretically produce enough energy to cover its consumption. In this work, the established ALMCC system simultaneously achieved the high level of CO2 fixation, energy recycle, and municipal wastewater treatment effectively and efficiently.

Effect of algal species and light intensity on the performance of an air-lift-type microbial carbon capture cell with an algae-assisted cathode

The performances were investigated for air-lift-type microbial carbon capture cells (ALMCCs) with Chlorella vulgaris and Chlorella sp. as cathodic microorganisms. The two ALMCC systems showed differences in CO2 fixation, lipid production and power generation. The ALMCC system with Chlorella vulgaris produced a maximum power density of 558.22 mW m−3, a CO2 fixation rate of 223.68 mg L−1 d−1 and lipid productivity of 21.75 mg L−1 d−1, indicating that Chlorella vulgaris performed better than Chlorella sp. By conducting further experiments with Chlorella vulgaris under different light intensities (2.4, 5.0, 8.9 and 11.4 W m−2), the ALMCC was found to be sensitive to light intensities. The maximum power outputs and CO2 fixation rate were observed under light intensity of 8.9 W m−2 (972.5 mW m−3 and 887.8 mg L−1 d−1, respectively). The lipid productivity was increased with the light intensity from 2.4 to 11.4 W m−2. However, there was no difference in lipid productivities between light intensities of 8.9 and 11.4 W m−2 (p > 0.05). These results suggested that 8.9 W m−2 was the optimal light intensity for CO2 fixation, lipid production and power generation of the ALMCC with Chlorella vulgaris.