Predicting spinel solid solutions using a random atom substitution method

Exploration of chemical composition and structural configuration space is the central problem in crystal structure prediction. Even in limiting structure space to a single structure type, many different compositions and configurations are possible. In this work, we attempt to address this problem using an extension to the existing ChemDASH code in which variable compositions can be explored. We show that ChemDASH is an efficient method for exploring a fixed-composition space of spinel structures and build upon this to include variable compositions in the Mn-Fe-Zn-O spinel phase field. This work presents the first basin-hopping crystal structure prediction method that can explore variable compositions.

Rapid annealing: minutes to enhance the green emission of the Tb3+-doped ZnGa2O4 nanophosphor with restricted grain growth

Rapid annealing boosted the green emission of the Tb3+:ZnGa2O4 nanophosphor within minutes.

Linear α-olefin production with Na-promoted Fe–Zn catalysts via Fischer–Tropsch synthesis

The production of linear alpha-olefins (α-olefins) is a practical way to increase the economic potential of the Fischer–Tropsch synthesis (FTS) because of their importance as chemical intermediates. Our study aimed to optimize Na-promoted Fe₁Zn_1.2O_x catalysts such that they selectively converted syngas to linear α-olefins via FTS at 340 °C and 2.0 MPa. The Fe₁Zn_1.2O_x catalysts were calcined at different temperatures from 350 to 700 °C before Na anchoring. The increase in the size of the ZnFe₂O₄ crystals comprising the catalyst had a negative effect on the reducibility of Fe oxides and the particle size of Fe₅C₂ during the reaction. The Na species in the catalyst restrained the reduction of Fe₁Zn_1.2O_x but facilitated the formation of Fe₅C₂. When pure Fe₁Zn_1.2O_x was calcined at 400 °C, the corresponding catalyst (i.e., Na_0.2/Fe₁Zn_1.2O_x (400)) exhibited higher catalytic activity and stability than the other catalysts for a 50 h reaction. Compared to the other catalysts, Na_0.2/Fe₁Zn_1.2O_x (400) enabled a higher number of active Fe carbides (Fe₅C₂) to intimately interact with the Na species, even though the catalyst had a lower total surface basicity based on surface area. The Na_0.2/Fe₁Zn_1.2O_x (400) showed a maximum hydrocarbon yield of 49.7% with a maximum olefin selectivity of 61.3% in the C1–C32 range. Examination of the reaction product mixture revealed that the Na_0.2/Fe₁Zn_1.2O_x catalysts converted α-olefins to branched paraffins (13.9–19.5%) via a series of isomerization, skeletal isomerization, and hydrogenation reactions. The Na_0.2/Fe₁Zn_1.2O_x (400) catalyst had a relatively low consumption rate of internal olefins compared to other catalysts, resulting in the lowest selectivity for branched paraffins. The Na_0.2/Fe₁Zn_1.2O_x (400) showed a maximum α-olefin yield (26.6%) in the range C2–C32, which was 27.9–50.0% higher than that of other catalysts. The α-olefin selectivity in the C5–C12 range for the Na_0.2/Fe₁Zn_1.2O_x (400) was 37.5% relative to the total α-olefins.

Intimate contact between Fe₅C₂ and Na₂O leads to high linear olefin selectivity with minimizing branched paraffin formation.

A new recipe for the rapid microwave synthesis of high quantum yield Mn2+-doped ZnGa2O4 phosphors for potential forensic applications

A microwave recipe for the synthesis of phase pure and crystalline Mn²⁺-doped ZnGa₂O₄ phosphors in 5 minutes.

Microwave solution route to ceramic ZnAl2O4 nanoparticles in 10 minutes: inversion and photophysical changes with thermal history

Within 10 minutes microwave synthesis using metal complexes can form crystalline ZnAl₂O₄ nanoparticles with significant inversion.

Albumin matrix assisted wet chemical synthesis of nanocrystalline MFe2O4 (M = Cu, Co and Zn) ferrites for visible light driven degradation of methylene blue by hydrogen peroxide

Nanocrystallite MFe₂O₄ (M = Cu, Co and Zn) ferrites synthesized via a facile wet chemical process assisted by albumin matrix are reported to exhibit significant photodegradation of methylene blue (MB) in the presence of H₂O₂ under visible light.

Synthesis and structural characterization of ZnxFe3−xO4 ferrite nanoparticles obtained by an electrochemical method

A series of ferrite nanoparticles with different Zn content were synthesized following a single-step electrochemical method in aqueous medium.