Peiqiang Li

The photoelectric catalytic reduction of CO2 to methanol on CdSeTe NSs/TiO2 NTs

The CdSeTe nanosheet (CdSeTe NS)/TiO2 nanotube (TiO2 NT) photoelectrocatalyst was obtained by the hydrothermal method by loading CdSeTe NSs onto TiO2 NTs which were prepared by an anodic oxidation method. The SEM and TEM results show that CdSeTe had a flaky structure with a large size of 300–400 nm and a small size of about 100 nm, which distributed on the TiO2 NT surface uniformly. The HRTEM and XRD characterization revealed that the CdSeTe NSs grew along the (100) and (002) orientations. Measured by UV-vis DRS and XPS, the energy band gap of the TiO2 NTs was narrowed from 3.20 eV to 1.48 eV by the introduction of the CdSeTe NSs, of which the conduction band and valence band are located at −0.46 eV and 1.02 eV, respectively. In the photoelectrocatalytic reduction CO2 process, the current density had a significant improvement after the decoration with the CdSeTe NSs, increasing from 0.31 mA cm−2 to 4.50 mA cm−2 at −0.8 V. Methanol was the predominant photoelectrocatalytic reduction product identified by chromatography, and it reached 1166.77 μmol L−1 after 5 h. In addition, the mechanism of the high efficiency photoelectrocatalytic reduction of CO2 to methanol was explained from the following aspects: energy band matching, high efficiency electron transmission and the stability of the catalyst.

One dimensional SnO2 NRs/Fe2O3 NTs with dual synergistic effects for photoelectrocatalytic reduction CO2 into methanol

The hydrothermal method was explored to prepare SnO2 nanorods (SnO2 NRs) with the special faces of (110) and (101) on the surface of Fe2O3 nanotubes (Fe2O3 NTs). According to the SEM and XRD results, the formation process of the hierarchically assembled SnO2 NRs was deduced. The SnO2 NRs/Fe2O3 NTs catalyst that had reached for 120 mins behaved the best photoelectrocatalytic properties. From the view of photocatalytic reduction, the conduction band (-0.75eV vs NHE) is negative enough to drive CO2 reduction, and the valence band (1.82eV) is positive enough to oxidize H2O to generate proton, and then the proton is used for CO2 reduction. From the electrocatalytic reduction point, the net CO2 reduction current density of the composite is 7.48 times that of Fe2O3 NTs at -1.1V, indicating that the electrocatalytic performance of Fe2O3 NTs is greatly enhanced by the introduction of 6-fold branched SnO2 NRs. The predominant reduction product is analyzed by GC was methanol. Herein, two synergistic effects are proved according to the methanol yields, one is the synergistic effect of the photocatalytic and electrocatalytic reduction, the other is the synergistic effect between SnO2 NRs and Fe2O3 NTs. The results indicated that the composite catalyst behaves excellent photoelectrocatalytic activity for CO2 reduction.

Different CdSeTe structure determined photoelectrocatalytic reduction performance for carbon dioxide

CdSeTe nanoparticles (CdSeTe NPs)/TiO2 nanotubes (TiO2 NTs) and CdSeTe nanosheets (CdSeTe NSs)/TiO2 NTs were fabricated by photoelectric deposition method and hydrothermal method, respectively. The band gap of the CdSeTe NPs/TiO2 NTs (1.24eV) is narrower than that of the CdSeTe NSs/TiO2NTs (1.48eV). The photoelectrochemical conversion efficiency of the CdSeTe NPs/TiO2 NTs is 2.72 times larger than that of the CdSeTe NSs/TiO2 NTs, manifesting that the CdSeTe NPs/TiO2 NTs possessed more excellent photocatalytic performance. Furthermore, the current density of electrocatalytic reduction CO2 on the CdSeTe NPs/TiO2 NTs was 2.47 times larger than that of the CdSeTe NSs/TiO2 NTs, showing the excellent electrocatalytic performance of the CdSeTe NPs/TiO2 NTs. The major product methanol was detected in the PEC reduction process on the two as-prepared materials. The yield reached 18.57mmolL-1 after 300min on CdSeTe NPs/TiO2NTs, which is 16 times larger than that of CdSeTe NSs/TiO2 NTs.

Stability of easily hydrolyzable beta-cypermethrin based O/W type drug-loading microemulsion

Abstract Four surfactants with different counter-ions were synthesized. The effect of their charges, ionic radii, and binding degree on the phase behavior of oil-in-water type drug-loading microemulsion was investigated. Counter ion with smaller ionic hydrated radius, strengthened the hydrophobicity and made the arrangement of micelle interface more compactly. When K+ was taken as a counter-ion, the arrangement tightness of interfacial film is highest and water penetration is most difficult. The solubilization location of the oil phase in the microemulsion was determined using pyrene as probe, and the influence law of solvent polarity to the solubilization location of the oil phase was obtained. The oil phase with smaller polarity was more conducive to occupy the inner space of micelle, which means it was beneficial to reduce the contact chance between beta-cypermethrin and osmotic water, thus the hydrolysis of beta-cypermethrin was reduced. For cyclohexanone solvent, the I1/I3 value was between 1.03 and 1.09, it indicated that the solubilization location of the oil phase was in a relatively smaller polarity environment. The microemulsion prepared with DBSK and cyclohexanone exhibited the minimum decomposition rate of beta-cypermethrin. Graphical Abstract