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Microwave-hydrothermal (M − H) synthesis of α-Sn(HPO4)2·H2O (α-SnP) was achieved here in as low as 5 min at 194 °C compared to several days by others previously. The use of microwaves in conjunction with the hydrothermal process enhanced the α-SnP synthesis reaction at least by two orders of magnitude. The super fast synthesis was apparently due to localized superheating where nucleation started and the reactions occurred very quickly in the localized superheated spots. The synthesized α-SnP was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). TEM revealed worm-like morphology at both low temperature and short duration of M − H treatment but at higher temperature platy morphology typical of layered phases resulted. The synthetic tin phosphate (α-SnP) phase is potentially useful as a cation exchanger, proton conductor and electrode material.

Here, we coined the term "clayene" for a single layer of clay and "few-layer clayene" for clays with 2-10 layers. Few-layer clayenes, which are Fe2+-rich and mica-type, were prepared hydrothermally at 200 °C and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM)/high-resolution transmission electron microscopy (HRTEM) to determine the crystalline phases and morphology, respectively. Chemical composition by energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy confirmed the iron-rich mica composition, and the latter also revealed the presence of both Fe2+ and Fe3+. Mossbauer spectroscopy further confirmed the presence of Fe2+ and Fe3+ and their proportions in the mica-type few-layer clayenes. All of the synthesized mica-type few-layer clayenes except one exhibited high specific surface areas (SSAs) ranging from 94 to 149 m2/g as determined by N2 adsorption-desorption isotherms and the Brunauer-Emmett-Teller (BET) equation. The high surface areas are in conformity with the crystal sizes calculated from XRD peaks and also as revealed by HRTEM. Taking advantage of the interfacial reactions of the high surface area of few-layer clayenes, two potential applications of clayenes were demonstrated in materials and environmental fields.

Anthracite briquettes were developed using mainly waste anthracite fines, plant byproducts of rice hulls and rice hull ash and silicon metal powder as an ecofriendly fuel and as an alternative to conventional coke used in a cupola furnace. Si metal powder reacts with anthracite to form SiC, which provides high mechanical strength to an anthracite briquette when it is exposed to a high temperature in the cupola furnace. Rice hull and rice hull ash, which are agricultural byproducts with high SiO2 content were investigated as partial substitutes for silicon as the former are inexpensive relative to silicon metal. The formation of SiC was investigated under different conditions using X-ray diffraction and transmission electron microscopy. In addition, unconfined compressive strength of the briquettes was measured when the rice hull or ash substituted Si powder partially or completely. When anthracite briquettes prepared with elemental Si powder and either rice hull ash or rice hull powder were pyrolyzed at 1400 °C for 2 h, SiC formed and the briquettes showed high mechanical strength in the range of 2000–4000 kPa, which is enough to keep their structural integrity in a cupola furnace.

Here, we report a remarkable 15 A nanolayered tin phosphate, Sn(HPO4)2·3H2O (SnP–H+ or SnP), and its clay-like gel, which are multifunctional and are prepared using earth-abundant Sn and P chemicals by a facile, environmentally benign and potentially cost-effective process. This new energy material is discovered here as the best proton conductor among all the known layered phosphates with a very high proton conductivity of over 1 × 10−2 S cm−1 at 100 °C for potential use in PEM fuel cells. But it is also a very good capacitor material with fast Li-storage kinetics (charging time of 13 s).