A method is provided for producing an article which is transparent to near-wave IR, mid-wave and Long-wave multi-spectral and IR wavelength in the region of 0.4 pm to 16 μm. The method includes the steps of (a) Producing ultra-fine powder of CaLa.sub.2S.sub.4 via SPLTS process, (b) followed by pretreatment of the ultra-fine powder under inert and reducing gas conditions including H.sub.2 or Argon or N.sub.2 or H.sub.2/H.sub.2S, H.sub.2S, and mixtures there of (c) followed by sieving the powder in 140 mesh screen and cold pressing the powder at 7000 psi for 7 min. into a disk shaped green body (d) then Cold-Isostatic Pressing (CIP) at 40,000 psi for 5 min in a rubber mold (e) finally sintered article of CaLa.sub.2S.sub.4 disk of 25.4 mm diameter with ultra-high density containing cubic phase of CaLa.sub.2S.sub.4 to yield IR transmission of a peak value of 57% within the IR wavelength range of 2 μm to 16 μm, either by using microwave sintering followed by hot isostatic press or spark plasma sintering followed by hot isostatic press or vacuum sintering at (3×10.sup.−6 torr) followed by hot isostatic press or hot press sintering followed by hot isostatic press and finally followed by mirror polished IR article, is obtained.

The present invention discloses a process for the preparation of metal sulphide quantum dots by using a very low cost sulphur precursor as a sulphur source. The metal sulphide quantum dots finds application in optical devices selected from photovoltaic cells, photodetectors and light-emission devices.

The present invention discloses a process for the preparation of metal sulphide quantum dots by using a very low cost sulphur precursor as a sulphur source. The metal sulphide quantum dots finds application in optical devices selected from photovoltaic cells, photodetectors and light-emission devices.

Methods of synthesizing Bi.sub.2S.sub.3-CdS particles in the form of spheres as well as properties of these Bi.sub.2S.sub.3-CdS particles are described. Methods of photocatalytic degradation of organic pollutants employing these Bi.sub.2S.sub.3-CdS particles and methods of preventing or reducing microbial growth on a surface by applying these Bi.sub.2S.sub.3-CdS particles in the form of a solution or an antimicrobial product onto the surface are also specified.

Methods of synthesizing Bi.sub.2S.sub.3-CdS particles in the form of spheres as well as properties of these Bi.sub.2S.sub.3-CdS particles are described. Methods of photocatalytic degradation of organic pollutants employing these Bi.sub.2S.sub.3-CdS particles and methods of preventing or reducing microbial growth on a surface by applying these Bi.sub.2S.sub.3-CdS particles in the form of a solution or an antimicrobial product onto the surface are also specified.

The invention relates to a composite oxide comprising CaO stabilised by Ca.sub.3Al.sub.2O.sub.6 (C3A), wherein the composite is in the form of particles. The mixed oxide composite is useful as a catalyst in the transesterification of triglycerides, e.g. in the production of biodiesel. Calcium leaching is more hindered in CaO—Ca.sub.3Al.sub.2O.sub.6 (2Ca/Al) than in CaO—Al.sub.2O.sub.3.

Biomineralization—the synthesis of inorganic materials using proteins—has recently gained interest as a low cost, green route for the production of metal chalcogenide semiconductor nanocrystals. Typical biomineralization approaches rely on proteins or biomolecules identified from organisms which possess a native biomineralization response. Disclosed herein is an alternative biomineralization approach for synthesizing metal chalcogenide nanocrystals which uses an artificially designed de novo protein. De novo proteins are non-natural proteins, allowing for facile modification of the protein through the tuning of amino acids within the sequence. This de novo protein was employed to produce size-controlled populations of semiconductor nanocrystals, with properties consistent with those produced using traditional routes.

Biomineralization—the synthesis of inorganic materials using proteins—has recently gained interest as a low cost, green route for the production of metal chalcogenide semiconductor nanocrystals. Typical biomineralization approaches rely on proteins or biomolecules identified from organisms which possess a native biomineralization response. Disclosed herein is an alternative biomineralization approach for synthesizing metal chalcogenide nanocrystals which uses an artificially designed de novo protein. De novo proteins are non-natural proteins, allowing for facile modification of the protein through the tuning of amino acids within the sequence. This de novo protein was employed to produce size-controlled populations of semiconductor nanocrystals, with properties consistent with those produced using traditional routes.

A method is provided for producing an article which is transparent to IR wavelength in the region of 4 μm to 9 μm. The method includes the steps of (a) Producing ultra-fine powders of ZnS, (b) followed by pretreatment of the ultra-fine powders under reduced gas conditions including H2, H2S, N2, Ar and mixtures there of (c) followed by vacuum (3×10.sup.−6 torr) treatment to remove oxygen and sulfates adsorbed to the surface disposing a plurality of nano-particles on a substrate, wherein said nanoparticles comprise ZnS with ultra-high purity of cubic phase; (b) subjecting the nano-particles to spark plasma sintering thereby producing a sintered ZnS product with IR transmission reaching 75% in the wavelength range of 4 μm to 9 μm.

A method is provided for producing an article which is transparent to IR wavelength in the region of 4 μm to 9 μm. The method includes the steps of (a) Producing ultra-fine powders of ZnS, (b) followed by pretreatment of the ultra-fine powders under reduced gas conditions including H2, H2S, N2, Ar and mixtures there of (c) followed by vacuum (3×10.sup.−6 torr) treatment to remove oxygen and sulfates adsorbed to the surface disposing a plurality of nano-particles on a substrate, wherein said nanoparticles comprise ZnS with ultra-high purity of cubic phase; (b) subjecting the nano-particles to spark plasma sintering thereby producing a sintered ZnS product with IR transmission reaching 75% in the wavelength range of 4 μm to 9 μm.