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The continuity equation revisited, including a subsurface electric field (E) in the space charge region of the semiconductor photocatalyst is used to assess the effect that the electric field has on the activity and selectivity of the photocatalyst. A mismatch between the experimental spectral dependence of the quantum yield and the corresponding absorption band may be an indicator of the existence of a space charge region in the solid photocatalyst.

Polarization deficiency and excess ion hydration free energy at an electric field E (ion hydration free energy at the field E subtracted by the ion hydration free energy at zero field) of hydrated calcium, sodium, and chloride ions is determined by Monte Carlo simulations. A primitive polarization model of electrolyte solution near charged interfaces is proposed.

A development of a microscopic model based on a novel generalization of the Becker-Doring equations of nucleation, which describes the stepwise growth of vesicles is shown. A preexisting vesicle provides a catalytic surface on which vesicle fragment can grow at an accelerated rate as per assumption and involves aggregation and fragmentation rate coefficients, which together determine an equilibrium solution.

Self-assembled monolayers (SAMs) of alkanethiols, HS(CH2)(sub n-1)CH3 absorbed on gold is used to explore the dynamics of energy exchange and thermalization in high-energy gas-surface collisions. The results suggest that long-range molecular motions involving up to 6 carbon atoms play the dominate role in controlling the dynamics of the gas-surface impact.

A study was conducted to analyze the spectral dependencies of the quantum yields of photoadsorption of donor molecules on the surfaces of Sc2O3 particulates during excitation in the spectral absorption area of photogenerated hole color centers. Results indicated that the quantum yields of photoadsorption correlated with the efficiency of the photophysical processes associated with carrier photogeneration and carrier transport toward the particle surface.

Research was conducted to examine the photoluminescence and transient spectroscopy of free base porphyrin aggregates. Four different types of aggregates whose absorption spectra were characterized by invariant Soret bands with bandwidths that were independent of the preparative approach were studied. Results demonstrate that the aggregates differ in their time-resolved absorption and fluorescence decay properties which may be attributed to differences in aggregate structures.

Utilization of water as an inexhaustible supply of a fuel (hydrogen) was predicted over a century ago by Jules Verne in The Mysterious Island. Since the oil crisis of 1973, considerable progress has been made in the search for alternative energy supplies. Although the water splitting process to generate simultaneously hydrogen and oxygen has been demonstrated (albeit the process is inefficient) by utilization of light energy, the technology is not mature enough to seriously bring it to pilot-plant demonstration. Much fundamental research remains to be done. The present paper examines the present status and looks at the perspectives of the technological progress, particularly in the high temperature thermochemical and photochemical fields with emphasis in the utilization of solar quantum and thermal photons.

A perovskite-like barium bismuthate of the BaBi2O4 class, Ba1.264(4)Bi1.971(4)O4, has been prepared by solid-state synthesis and subsequently characterized by a number of experimental techniques (XPS, DRS, SEM, EDX and Raman spectroscopy), as well as by a DFT computational approach using the GGA Perdew–Burke–Ernzerhof (PBE) density functional to determine the energy band structure. XRD peaks were indexed to a rhombohedral cell (R3¯m) with parameters close to Ba0.156Bi0.844O1.422 (i.e., to Ba0.439Bi2.374O4), which upon Rietveld refinement gave Ba1.264(4)Bi1.971(4)O4. The Bi–O bond lengths determined from this refinement (1.86 and 2.31 Å) accorded with the bond lengths estimated from Raman spectra (1.97 and 2.26 Å). DFT calculations revealed the bismuthate to display two bandgaps that correspond to lower-energy indirect (2.28 eV) and to higher-energy direct (2.36 eV) electronic transitions in good agreement with the experimental bandgaps of 2.26 eV and 2.43 eV, respectively, from Tauc plots of DRS spectra. Relative to the indirect bandgap energy of 2.26 eV, the energies of the valence band and of the conduction band were, respectively, +1.14 eV and −1.12 eV. The photoactivity of Ba1.264(4)Bi1.971(4)O4 was examined toward the photoreduction of the greenhouse gas CO2 in aqueous media photoelectrochemically yielding alcohols and alkanes, while in the gas phase in an infrared cell reactor the products were carbon monoxide and alkanes. [ABSTRACT FROM AUTHOR]

The reexamination of the Langmuir-Hinshelwood (LH) kinetic model along with several other dogmas that continue to propagate in the heterogeneous photocatalytic landscape is presented. The priori assumed validity of the LH kinetic model in heterogenous photocataylsis and the recombination of photogenerated free charge carriers on the solid photocataylsis by the band-to-band recombination pathway is reexamined.

The study was aimed at examining the effect(s) of surface photochemical reactions involving H(sub 2), O(sub 2), NH(sub 3), and CO(sub 2) on the photocoloration of ZrO(sub 2) in particular, and metal oxides in general. The effect of a nonphotocatalytic reaction occurring on the surface of an irradiated wide band gap metal oxide is seen as the influence of photosimulated adsorption on the photocoloration of the metal oxide specimen.

The results of a mechanistic study into the formation of various states of oxygen produced over irradiated zirconia (ZrO2) under various conditions. The photooxiodation of hydrogen in the presence of molecular oxygen over irradiated powdered ZrO2 as a model reaction is examined.

The results of studies on the solonitsyn memory effect in gas-solid heterogeneous systems with respect to photo-stimulated adsorption of molecular hydrogen, oxygen and methane on a dielectric metal oxide surface are mentioned. The experimental data is explained using a simple model.