A preparation method of a tetragonal NaV.sub.2O.sub.5.H.sub.2O nanosheet-like powder includes steps of: (Step 1) simultaneously adding NaVO.sub.3 and Na.sub.2S.9H.sub.2O into deionized water, and then magnetically stirring, and obtaining a black turbid solution; (Step 2) sealing after putting the black turbid solution into an inner lining of a reaction kettle, fixing the sealed inner lining in an outer lining of the reaction kettle, placing the reaction kettle into a homogeneous reactor, and then performing a hydrothermal reaction; and (Step 3) after completing the hydrothermal reaction, naturally cooling the reaction kettle to the room temperature, and then alternately cleaning through water and alcohol, and then collecting a product, drying the product, and finally obtaining the tetragonal NaV.sub.2O.sub.5.H.sub.2O nanosheet-like powder with a thickness in a range of 30-60 nm and a single crystal structure grown along a (002) crystal orientation.

The present invention discloses a BiOCl photocatalyst with a super degradation effect. BiOCl is prepared into a special micro-nano ellipsoid structure which significantly improves catalysis efficiency under visible light. With the present invention, degradation rates with gas phase formaldehyde, Congo red solution and hexavalent chromium solution can reach above 90%. Moreover, due to a stable structure, the BiOCl photocatalyst has desired reusability which enables a lower cost of the photocatalyst and wider use in the field of environmental pollution treatment.

Provided is a piezoelectric thin film device containing: a first electrode layer; and a piezoelectric thin film. The first electrode layer contains a metal Me having a crystal structure. The piezoelectric thin film contains aluminum nitride having a wurtzite structure. The aluminum nitride contains a divalent metal element Md and a tetravalent metal element Mt. [Al] is an amount of Al contained in the aluminum nitride, [Md] is an amount of Md contained in the aluminum nitride, [Mt] is an amount of Mt contained in the aluminum nitride, ([Md]+[Mt])/([Al]+[Md]+[Mt]) is 36 to 70 atom %. L.sub.ALN is a lattice length of the aluminum nitride in a direction that is approximately parallel to a surface of the first electrode layer with which the piezoelectric thin film is in contact, L.sub.METAL is a lattice length of Me in a direction, and L.sub.ALN is longer than L.sub.METAL.

A 3D structure of the graphite-titanium-nanocomposite complex and a method of preparing the graphite-titanium-nanocomposite complex are disclosed. The Graphite-titanium-nanocomposite complex includes a metal core associated with the two phases, amine functionalized graphite, and amine functionalized titanium. The method of preparation includes amine functionalizing of graphite and titanium with coupling agents to produce amine functionalized titanium and graphite, further mixing with a metal ion solution for synthesizing an ion complex. Trisodium citrate solution and sodium borohydride solution is added to the ion complex to prepare a 3D structure of the graphite-titanium-nanocomposite complex, employed as a catalyst.

A method of agglomerating nanoparticles to form larger agglomerates is shown. The nanoparticles are mixed with a resin to form a first mixture (803) of agglomerates, having sizes over a range that includes agglomerates considered to be too large, suspended in the resin. A bead milling cylinder (802) produces a second mixture (808) with fewer large agglomerates. A filter (1001) removes the remaining large agglomerates. The resulting mill base is cut with a solvent before deployment.

A method, including irradiating graphene oxide (GO) with a beam of light or radiation to form reduced graphene oxide (RGO) in a three-dimensional (3D) pattern, wherein the RGO is porous RGO with pores having sizes tuned by controlling the beam of light or radiation.

A preparation method of a tetragonal NaV.sub.2O.sub.5.H.sub.2O nanosheet-like powder includes steps of: (S1) simultaneously adding NaVO.sub.3 and Na.sub.2S.9H.sub.2O into deionized water, and then magnetically stirring, and obtaining a black turbid solution; (S2) sealing after putting the black turbid solution into an inner lining of a reaction kettle, fixing the sealed inner lining in an outer lining of the reaction kettle, placing the reaction kettle into a homogeneous reactor, and then performing a hydrothermal reaction; and (S3) after completing the hydrothermal reaction, naturally cooling the reaction kettle to the room temperature, and then alternately cleaning through water and alcohol, and then collecting a product, drying the product, and finally obtaining the tetragonal NaV.sub.2O.sub.5.H.sub.2O nanosheet-like powder with a thickness in a range of 30-60 nm and a single crystal structure grown along a (002) crystal orientation.

Provided is a molybdenum sulfide that is ribbon-shaped and particularly suitable for a hydrogen generation catalyst. Disclosed are a ribbon-shaped molybdenum sulfide, in which 50 particles as measured by observation with a scanning electron microscope (SEM) have a shape of, on average, 500 to 10000 nm in length, 10 to 1000 nm in width, and 3 to 200 nm in thickness; a method for producing the ribbon-shaped molybdenum sulfide, including: (1) heating a molybdenum oxide at a temperature of 200 to 1000 C. in the presence of a sulfur source; or (2) heating a molybdenum oxide at a temperature of 100 to 800 C. in the absence of a sulfur source, and then heating the molybdenum oxide at a temperature of 200 to 1000 C. in the presence of a sulfur source; and a hydrogen generation catalyst including the ribbon-shaped molybdenum sulfide.

A nanocrystal production method includes a light irradiation step of applying light to a surface of a metal material immersed in water to form nanocrystals on the surface. In this nanocrystal production method, the metal material contains iron, the nanocrystal contains at least one of iron oxide and iron hydroxide, and in the spectrum of the light, a wavelength at which the intensity is maximum is not less than 360 nm and less than 620 nm.

A quantum dot including a core comprising a first semiconductor nanocrystal including a zinc chalcogenide and a semiconductor nanocrystal shell disposed on the surface of the core and comprising zinc, selenium, and sulfur. The quantum dot does not comprise cadmium, emits blue light, and may exhibit a digital diffraction pattern obtained by a Fast Fourier Transform of a transmission electron microscopic image including a (100) facet of a zinc blende structure. In an X-ray diffraction spectrum of the quantum dot, a ratio of a defect peak area with respect to a peak area of a zinc blende crystal structure is less than about 0.8:1. A method of producing the quantum dot, and an electroluminescent device including the quantum dot are also disclosed.