The aim of this review article on recent developments of mechanochemistry (nowadays established as a part of chemistry) is to provide a comprehensive overview of advances achieved in the field of atomistic processes, phase transformations, simple and multicomponent nanosystems and peculiarities of mechanochemical reactions. Industrial aspects with successful penetration into fields like materials engineering, heterogeneous catalysis and extractive metallurgy are also reviewed. The hallmarks of mechanochemistry include influencing reactivity of solids by the presence of solid-state defects, interphases and relaxation phenomena, enabling processes to take place under non-equilibrium conditions, creating a well-crystallized core of nanoparticles with disordered near-surface shell regions and performing simple dry time-convenient one-step syntheses. Underlying these hallmarks are technological consequences like preparing new nanomaterials with the desired properties or producing these materials in a reproducible way with high yield and under simple and easy operating conditions. The last but not least hallmark is enabling work under environmentally friendly and essentially waste-free conditions (822 references).

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Hallmarks of mechanochemistry: From nanoparticles to technology

BaTiO3 is used as a target catalyst to probe the influence of ferroelectricity on the decolorization of a typical dye molecule—Rhodamine B—under simulated solar light. We show that there is a 3-fold increase in the decolorization rate using BaTiO3 with a high tetragonal content compared to predominantly cubic material. This is ascribed to the ferroelectricity of the tetragonal phase. The influence of ferroelectricity ensures a tightly bound layer of dye molecule and also acts to separate the photoexcited carriers due to the internal space charge layer. Both of these features act to enhance the catalytic performance. When nanostructured Ag is photochemically deposited on the surface of the BaTiO3, we find a further increase in the reaction rate that gives complete decolorization of the dye in around 45 min.

Effect of Ferroelectricity on Solar-Light-Driven Photocatalytic Activity of BaTiO3—Influence on the Carrier Separation and Stern Layer Formation

In this work, different mole ratio percentage of nanocrystalline anatase TiO2/porous nanosized BiFeO3 (T/P-BFO) nanocomposites with effective contacts have been fabricated by putting the as-prepared P-BFO into the TiO2 sol, followed by drying at 80 °C and then calcining at 450 °C for 2 h. The photoactivities of the obtained products for pollutant degradation and H2 evolution were measured. It is clearly demonstrated by means of the steady-state surface photo-voltage spectra, the transient-state surface photovoltage responses, and the photoluminescence spectra that the photogenerated charge carriers in the T/P-BFO nanocomposites with a proper mole ratio percentage of TiO2 (9%) display much long lifetime and high separation in comparison to the resulting P-BFO alone. This is well responsible for the enhanced activities for degrading gas-phase acetyldehyde, the liquid-phase phenol, and for producing H2 under visible-light irradiation. Based on the measurements of formed hydroxyl radical amount and photoelectrochemical behavior, it is suggested that the improved separation of photogenerated charges in the fabricated T/P-BFO nanocomposite is mainly attributed to the spatial transfer of visible-light-excited (λ ≤ 500 nm) high-energy electrons of P-BFO to TiO2. This work will provide a feasible route to enhance the photoactivities of visible-light responsive oxide composites as photocatalysts for efficient solar energy utilization.

Enhanced visible-light activities of porous BiFeO3 by coupling with nanocrystalline TiO2 and mechanism

A review on MnZn ferrites: Synthesis, characterization and applications.

Fabrication of barium titanate by binder jetting additive manufacturing technology

Barium titanate is the first ferroelectric ceramics and a good candidate for a variety of applications due to its excellent dielectric, ferroelectric and piezoelectric properties. Barium titanate is a member of a large family of compounds with the general formula ABO3 called perovskites. Barium titanate can be prepared using different methods. The synthesis method depends on the desired characteristics for the end application. The used method has a significant influence on the structure and properties of barium titanate materials. In this review paper, Part I contains a study of the BaTiO3 structure and frequently used synthesis methods.

J.D. Bobić

Papers

History and challenges of barium titanate: Part I

Properties of lanthanum doped BaTiO3 produced from nanopowders

Structure and properties of Ni–Zn ferrite obtained by auto-combustion method

Dielectric and magnetic properties of BaTiO3 –NiFe2O4 multiferroic composites

Electrical properties of lanthanum doped barium titanate ceramics