Physical Chemistry Chemical Physics
ISSN / EISSN : 1463-9076 / 1463-9084
Published by: Royal Society of Chemistry (10.1039)
Total articles ≅ 43,577
Latest articles in this journal
Physical Chemistry Chemical Physics, Volume 23, pp 15390-15390; doi:10.1039/d1cp90152d
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Physical Chemistry Chemical Physics; doi:10.1039/d1cp01090e
The excited-state decay dynamics of 2-ethylpyrrole following UV excitation at a wavelength range of 254.8-218.0 nm is investigated in detail using femtosecond time-resolved photoelectron imaging method. The time-resolved photoelectron spectra at all pump wavelengths are carefully analysed and the following picture is derived: At the longest pump wavelengths (254.8, 248.3 and 246.1 nm), 2-ethylpyrrole is excited to the S1(1πσ*) state having a lifetime of about 50 fs. At 248.3, 246.1 and 237.4 nm, another excited state of Rydberg character is excited. The lifetime of this state is ~570 fs at 237.4 nm and becomes slightly longer at other two pump wavelengths. At the shortest pump wavelengths (230.8 and 218.0 nm), 2-ethylpyrrole is excited to a state which is tentatively assigned to the 1ππ* state, having a lifetime of 88±15 and 55±10 fs for the longer and shorter pump wavelengths, respectively.
Physical Chemistry Chemical Physics; doi:10.1039/d1cp02777h
Novel ferrocene functionalized graphene with different molecular structures were designed, fabricated and characterized using SEM, EDS, FTIR, XPS and RAMAN methods. SEM results show the two-dimension structure of the prepared catalysts, and the active metal Fe is uniformly distributed on the surface of graphene. The FTIR, XPS and RAMAN results confirmed the successful preparation of ferrocene functionalized graphene. The catalytic effects of the as-synthesized catalysts for thermal decomposition of energetic TKX-50 were monitored by DSC, and the corresponding kinetic parameters were calculated using multi kinetic methods including traditional and nonlinear models. The results showed that the prepared ferrocene functionalized graphene can effectively promote the thermal decomposition of TKX-50 with the reduced decomposition peak temperatures and activation energies. In addition, the effects of ferrocene functionalized graphene for TKX-50 decomposition are reflected in both high and low temperature stages, and the effect on high temperature stage is more significant. The outstanding catalytic activity of ferrocene functionalized graphene is related not only to the good dispersion of active Fe, but also to the enhanced interaction of small molecule products on two-dimensional graphene. Among the ferrocene functionalized graphene studied, G-792-Fe and G-902-Fe owns better catalytic effects on the thermal decomposition of TKX-50, which can be used as a candidate catalyst for TKX-50 based solid propellant.
Physical Chemistry Chemical Physics; doi:10.1039/d1cp02568f
The interaction between carbon dioxide and planar carboxylic acids has been investigated through the analysis of the microwave spectrum of the acrylic acid·CO2 complex and quantum chemical modeling of the...
Physical Chemistry Chemical Physics; doi:10.1039/d1cp01002f
Zn(ii)–Fe(iii)carboxylate decomposition favours Zn- and Fe-rich phases separation resulting in ZnO/ZnFe2O4 nanocomposites: systems of superparamagnetic spinel ZnFe2O4 nanoparticles/nanoclusters of high inversion degree.
Physical Chemistry Chemical Physics; doi:10.1039/d1cp02534a
The concept of aggregation-induced emission represents a means to rationalise photoluminescence of usually nonfluorescent excimers in solid-state materials. In this publication, we study the photophysical properties of selected diaminodicyanoquinone (DADQ) derivatives in the solid state using a combined approach of experiment and theory. DADQs are a class of high-dipole organic chromophores promising for applications in non-linear optics and light-harvesting devices. Among the compounds investigated, we find both aggregation-induced emission and aggregation-caused quenching effects rationalised by calculated energy transfer rates. Analysis of fluorescence spectra and lifetime measurements provide the curious result that (at least) two emissive species seem to contribute to the photophysical properties of DADQs. The main emission peak is notably broadened in the long-wavelength limit and exhibits a blue-shifted shoulder. We employ high-level quantum-chemical methods to validate a molecular approach to a solid-state problem and show that the complex emission features of DADQs can be attributed to a combination of H-type aggregates, monomers, and crystal structure defects.
Physical Chemistry Chemical Physics; doi:10.1039/d1cp02068d
Metal/oxide support perimeter sites are known to provide unique properties because the nearby metal changes the local environment on the support surface. In particular, the electron scavenger effect reduces the energy necessary for surface anion desorption, thereby contributes to activation of the (reverse) Mars-van Krevelen mechanism. This study investigated the possibility of such activation in hydrides, carbides, nitrides, and sulfides. The WFs of known hydrides, carbides, nitrides, oxides, and sulfides with group 3, 4, or 5 cations (Sc, Y, La, Ti, Zr, Hf, V, Nb, and Ta) were calculated. The WFs of most hydrides, carbides, and nitrides are smaller than the WF of Ag, implying that the electron scavenger effect may occur when late transition metal nanoparticles are adsorbed on the surface. The WF of oxides and sulfides decrease when reduced. The surface anion vacancy formation energy correlates well with the bulk formation energy in carbides and nitrides, while almost no correlation is found in hydrides because of the small range of surface hydrogen vacancy formation energy values. The electron scavenger effect is explicitly observed in nanorods adsorbed on TiH2 and Ti2O3; the surface vacancy formation energy decreases at anion sites near the nanorod, and charge transfer to the nanorod happens when an anion is removed at such sites. Activation of hydrides, carbides, and nitrides by nanorod adsorption and screening support materials through WF calculation are expected to open up a new category of supported catalysts.
Physical Chemistry Chemical Physics; doi:10.1039/d1cp03036a
Solar energy absorption is a very important field in photonics. The successful development of an efficient, wide-band solar absorber will be an extremely powerful impetus in this field. We proposed an ultra-wideband(UWB) solar energy absorber composed of Ti ring and SiO2-Si3N4-Ti thin films. In the range of 300 nm-4000 nm, the wide band with absorption efficiency of more than 90% can reach 3683 nm, and it has four absorption peaks with high absorptivity. Moreover, the weighted average absorption efficiency of the solar absorber under AM1.5 is kept above 97.03%, which makes it have great potential in the field of solar energy absorption. Moreover, we proved that the polarization is insensitive by analyzing the absorption characteristics at arbitrary polarization angles. For both transverse electric(TE) and transverse magnetic(TM) modes, UWB absorption is maintained at more than 90% in the wide incidence angle range of 60°. The UWB solar energy absorbers has great potential in a variety of applications, such as converting solar light and heat into electricity for public use, reducing the side effects of coal-fired power generation. It can also be used in information detection and infrared thermal imaging with its UWB characteristics.
Physical Chemistry Chemical Physics, Volume 23, pp 14957-14968; doi:10.1039/d1cp90148f