The
impressive optoelectronic performance and low production cost
of metal halide perovskites have inspired applications well beyond
efficient solar cells. Herein, we widen the materials engineering
options available for the efficient and selective photocatalytic oxidation
of benzylic alcohols, an industrially significant reaction, using
formamidinium lead bromide (FAPbBr3) and other perovskite-based
materials. The best performance was obtained using a FAPbBr3/TiO2 hybrid photocatalyst under simulated solar illumination.
Detailed optical studies reveal the synergetic photophysical pathways
arising in FAPbBr3/TiO2 composites. An experimentally
supported model rationalizing the large conversion enhancement over
the pure constituents shows that this strategy offers new prospects
for metal halide perovskites in photocatalytic applications.
The potential effects of carbonaceous nanomaterials (CNMs) on agricultural plants are of concern. However, little research has been performed using plants cultivated to maturity in soils contaminated with various CNMs at different concentrations. Here, we grew soybean for 39 days to seed production in soil amended with 0.1, 100, or 1000 mg kg of either multiwalled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), or carbon black (CB) and studied plant growth, nodulation, and dinitrogen (N) fixation potential. Plants in all CNM treatments flowered earlier (producing 60% to 372% more flowers when reproduction started) than the unamended controls. The low MWCNT-treated plants were shorter (by 15%) with slower leaf cover expansion (by 26%) and less final leaf area (by 24%) than the controls. Nodulation and N fixation potential appeared negatively impacted by CNMs, with stronger effects at lower CNM concentrations. All CNM treatments reduced the whole-plant N fixation potential, with the highest reductions (by over 91%) in the low and medium CB and the low MWCNT treatments. CB and GNPs appeared to accumulate inside nodules as observed by transmission electron microscopy. CNM dispersal in aqueous soil extracts was studied to explain the inverse dose-response relationships, showing that CNMs at higher concentrations were more agglomerated (over 90% CNMs settled as agglomerates >3 μm after 12 h) and therefore proportionally less bioavailable. Overall, our findings suggest that lower concentrations of CNMs in soils could be more impactful to leguminous N fixation, owing to greater CNM dispersal and therefore increased bioavailability at lower concentrations.
We report a new strategy to synthesize the hierarchical mesoporous zeolite through design of mesoscale cationic surfactant cetyltrimethylammonium bromide (CTAB) micelle with cosolvent tertbutyl alcohol (TBA) and the 1,3,5-trimethylbenzene (TMB) additive, by which the formation of hierarchical mesostructure arose from the condensing of zeolite fragments on the mesoscale surfactant micelles. The hierarchical mesoporous silica with zeolite Y or sodalite fragment is synthesized for the first time, which exhibited both the mesostructure and the typical diffraction of zeolite. XRD, N 2 adsorption-desorption, 27 Al MAS NMR, FTIR, and NH 3 -TPD techniques were employed to characterize the resulting samples, and the adsorption of NPYR (N-nitrosopyrrolidine) and NNN (N-nitrosonornicotine) were performed to assess the adsorptive capability of the zeolitic mesoporous materials. The MS3-4t-5b sample synthesized by assembling zeolite gel exhibited the adsorptive capacity comparable to NaY zeolite for trapping NPYR in airflow but four times superior to NaY for adsorbing bulky nitrosamine NNN in solution because of its hierarchical mesostructure.
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