Titanium dioxide, TiO2, is an important photocatalytic material that exists as two main polymorphs, anatase and rutile. The presence of either or both of these phases impacts on the photocatalytic performance of the material. The present work reviews the anatase to rutile phase transformation. The synthesis and properties of anatase and rutile are examined, followed by a discussion of the thermodynamics of the phase transformation and the factors affecting its observation. A comprehensive analysis of the reported effects of dopants on the anatase to rutile phase transformation and the mechanisms by which these effects are brought about is presented in this review, yielding a plot of the cationic radius versus the valence characterised by a distinct boundary between inhibitors and promoters of the phase transformation. Further, the likely effects of dopant elements, including those for which experimental data are unavailable, on the phase transformation are deduced and presented on the basis of this analysis.

https://link.springer.com/content/pdf/10.1007%2Fs10853-010-5113-0.pdf

Review of the anatase to rutile phase transformation

Pore size determination in modified micro- and mesoporous materials. Pitfalls and limitations in gas adsorption data analysis

The Role of Inorganic Polymer Technology in the Development of ‘Green Concrete’

Understanding the relationship between geopolymer composition, microstructure and mechanical properties

Carbon dioxide equivalent (CO2-e) emissions: A comparison between geopolymer and OPC cement concrete

New Trends in the Chemistry of Inorganic Polymers for Advanced Applications

AlN powders were synthesized by gas-reduction- nitridation of γ-Al2O3 powders using NH3 and C3H8 as reactant gases. AlN was identified from the products that synthesized at 1100-1400 oC for 120 min in the NH3-C3H8 gas flow, and it was confirmed that AlN can be easily fabricated by the gas-reduction-nitridation of γ-Al2O3. The products synthesized at 1100oC for 120min contained unreacted γ-Al2O3. By the 27A1 MAS NMR spectra, Al-N bonding in the product increased with an increase in the nitridation ratio of the tetrahedral AlO4 shoulder which decreased prior to that of the octahedral AlO6 shoulder. It seems that γ-Al2O3 was preferentially nitrided from AlO4 rather than AlO6. AlN nano particles were easily converted directly from γ -Al2O3 at a low temperature because the AlO4 within γ-Al2O3was preferentially nitrided.

Formation Mechanism of Nano AlN Powder by Gas-Reduction-Nitridation

Evolution of Crystalline Aluminates from Hybrid Gel‐Derived Precursors Studied by XRD and Multinuclear Solid State MAS NMR. Part 3. Lanthanum Hexaluminate, LaAl11O18.

The sialon research programme at Industrial Research Ltd., New Zealand, comprises fundamental and strategic studies funded by central government that underpin an applied science and technology transfer programme designed in association with industry partners and supported through joint government-industry funding initiatives. The paper surveys current and recent research into a range of sialon fabrication processes, bodies and composites with particular emphasis on O-sialon.

Synthesis, Densification and Properties of SiAlON Bodies and Composites

Belite cement was prepared using nano-silicas extracted from three different agricultural wastes – black rice husk ash (BRHA), bagasse ash (BA), and palm oil fuel ash (POFA) – which were reacted at 1200 − 1400 °C with CaC2 residue as calcium source. The product was compared with that from CaCO3. Nano-silica extracted from BRHA was of very fine particle size (surface area 312.4 m2/g and V/S ratio 0.35 × 106 cm) and being highly reactive, forms β-C2S at lower firing temperatures; however, at higher temperatures, less-desirable γ-polymorphs are formed. Nano-silica extracted from POFA contains Na2O, Al2O3, and K2O impurities, which stabilize the β and α-forms and delay the transformation to γ-phase. This is reflected in relatively high compressive strength at firing temperature above 1200 °C, compared to other mixtures. Thus, these results indicate that the best combination of these waste materials for the preparation of belite cement phases is POFA ash and CaC2 residue.

/pdf/comparative-study-on-the-preparation-of-belite-cement-from-1fyjh0o6.pdf

Kenneth J. D. MacKenzie

Papers

New Trends in the Chemistry of Inorganic Polymers for Advanced Applications

Formation Mechanism of Nano AlN Powder by Gas-Reduction-Nitridation

Evolution of Crystalline Aluminates from Hybrid Gel‐Derived Precursors Studied by XRD and Multinuclear Solid State MAS NMR. Part 3. Lanthanum Hexaluminate, LaAl11O18.

Synthesis, Densification and Properties of SiAlON Bodies and Composites

Comparative study on the preparation of belite cement from nano-silicas extracted from different agricultural wastes with calcium carbide residue