Effects of Nanoparticle Size and Morphology on IR Diffuse Reflection Spectra

Two kinds of nanopowders were studied.One is NiFe 2O 4 spherical nanopowders which have different particle sizes.Another is ZnO nanopowders including two series of spherical particles and tetrapod nanowhiskers.Through measuring the infrared diffuse reflection spectra of nanopowders,it can be found that the particle size and morphology affect the infrared diffuse reflection spectra.For the NiFe 2O 4 nanopowders the smaller the particle size,the larger the K-M value.And when the particle size is large enough,the effect of the particle size on infrared diffuse reflection spectra would disappear.For the ZnO nanopowders the effects of the particle size and morphology are more special.The effect of the particle sizes of tetrapod whisker nanopowders on infrared diffuse reflection spectra is more than that of spherical nanopowders.

Multi－diffused Reflection Spectroscopy of Rare Earths Doped LaOCl Powder Samples and the Calculation of Quantum Efficiency

The excitation and emission spectra, the relaxation time of principal spectral lines and multi-diffused reflection spectra in LaOCl: Er, LaOCl: Ho powder samples were measured. The diffused absorption spectrum was derived from the multi-diffused reflection spectrum. According to Judd-Ofelt theory,the intensity parameters, radiative transition probabilities and quantum efficiencies of luminescence emission were calculated. Then comparison with erbium and holmium doped floride glass and other matrices were made.

Application of Short-wave Near-infrared Reflectance Spectroscopy in Controlling Extract of Fructus Cnidii Using Supercritical Carbon Dioxide

Fructus cnidii （Chinese name shechuangzi） is the fruit produced by Cnidium monnieri （L.） Cusson （Umbelliferae）. It is a perennial herb that is used to treat skin-related diseases and gynecopathyell. Recent pharmacological studies have revealed crude extracts or components isolated from fructus cnidii possess antiallergic, antipruritic, antidermatophytic, antibacterial, antifungal, and antiosteoporotic activities. Osthole and imperatorin are the major compounds present in shechuangzi. They are often used as standards for the evaluation of the quality of shechuangzi products.

Highly efficient photo-thermal synergistic catalysis of CO_(2)methanation over La1-xCexNiO_(3)perovskite-catalyst

Solar-driven photo-thermal catalytic CO_(2)methanation reaction is a promising technology to alleviate the problems posed by greenhouse gases emissions.However,designing advanced photo-thermal catalysts remains a research challenge for CO_(2)methanation reaction.In this work,a series of ABO3(A=lanthanide,B=transition metal)perovskite catalysts with Ce-substituted LaNiO3(La1-xCexNiO3,x=0,0.2,0.5,0.8,1)were synthesized for CO_(2)methanation.The La0.2Ce0.8NiO3 exhibited the highest CH4 formation rate of 258.9 mmol·g^(-1)·hcat-1,CO_(2)conversion of 55.4%and 97.2%CH4 selectivity at 300℃with the light intensity of 2.9 W·cm^(-2).Then the catalysts were thoroughly analyzed by physicochemical structure and optical properties characterizations.The partial substitution of the A-site provided more active sites for the adsorption and activation of CO_(2)/H_(2).The sources of the active sites were considered to be the oxygen vacancies(Ov)created by lattice distortions due to different species of ions(La^(3+),Ce^(4+),Ce^(3+))and exsolved Ni0 by H_(2)reduction.The catalysts have excellent light absorption absorbance and low electron-hole(e-/h+)recombination rate,which greatly contribute to the excellent performance in photo-thermal synergistic catalysis(PTC)CO_(2)methanation.The results of in situ irradiated electron paramagnetic resonance spectrometer(ISI-EPR)and ISI-X-ray photoelectron spectroscopy(XPS)indicated that the aggregation of unpaired electrons near the defects and Ni metal(from La and Ce ions to Ov and Ni0)accelerated adsorption and activation of CO_(2)/H_(2).At last,the catalyst properties and structure were correlated with the proposed reaction mechanism from the in situ diffuse reflection infrared Fourier transform spectrum(DRIFTS)measurements.The in situ precipitation of the B-site enhanced the dispersion of Ni,while its enriched photoelectrons upon illumination further promote hydrogen dissociation.More H^(*)spillover accelerated the rate-determining step(RDS)of HCOO*hydrogenation.This work provides the theoretical basis for the development of catalysts and industrial application.