A ZSM-23 zeolite and a process for preparing the same and use thereof are provided. The total acid amount of the ZSM-23 zeolite is 0.05-0.25 mmol/g, preferably 0.06-0.22 mmol/g, more preferably 0.06-0.20 mmol/g. The strong acid content of the ZSM-23 zeolite is 5-33%, preferably 7-33%, more preferably 9-33%, or further preferably 7-31%, further more preferably 10-28% of the total acid amount. The strong acid refers to an acid having a desorption temperature of 350 C. or higher in an NH3 temperature programmed desorption (NH3-TPD). The ZSM-23 zeolite has a low strong acid content.

An embodiment of the present specification provides a method for preparing a catalyst for preparing a carbon nanotube, comprising: (a) dissolving a main catalyst precursor, a support precursor, a cocatalyst precursor and a precipitation inhibitor in a solvent to prepare a precursor solution; and (b) pyrolyzing the precursor solution by spraying the precursor solution into a reactor, wherein a mole fraction of the precipitation inhibitor to the cocatalyst precursor is 0.1 to 1.5.

Proposed are an unsupported metallic catalyst for a selective ring-opening (SRO) reaction and a method of using the same catalyst, wherein the catalyst contains nickel (Ni), molybdenum (Mo), and tungsten (W).

A catalyst for production of carboxylic acid ester, containing: catalyst metal particles; and a support supporting the catalyst metal particles, wherein a bulk density of the catalyst for production of carboxylic acid ester is 0.50 g/cm.sup.3 or more and 1.50 g/cm.sup.3 or less, when a particle diameter, at which a cumulative frequency is x % in a particle diameter distribution based on a volume of the catalyst for production of carboxylic acid ester, is defined as D.sub.x, D.sub.10/D.sub.50?0.2 and D.sub.90/D.sub.50?2.5 are satisfied, and when a half-width of the particle diameter distribution is defined as W, W/D.sub.50?1.5 is satisfied.

The present invention provides zeolite hollow spheres in which zeolite crystals grow to form a framework of macropore through a hydrothermal crystallization process using the hydrophilic surface of a carbon sphere as a hard template, wherein the zeolite framework is an ordered, porous crystalline zeolite material with a number of channels or pores interconnected, which has pore structures including mesopores and micropores. The zeolite hollow spheres of the present invention can be used for various purposes such as catalysts and adsorbents.

A catalyst comprising a barium niobate-based cubic perovskite structure where, Mg and Ca has been used to dope the niobium sites along with Fe, Ni, Co, Y, and Pr.

A preparation method of a polyester is provided. The method includes the following steps: allowing a raw material including a diacid and a diol to contact a monoclinic nano-TiO2 (namely, TiO2(B)) catalyst, and conducting an esterification reaction and a polycondensation reaction sequentially to obtain the polyester. The method can efficiently catalyze the synthesis of the polyester and avoid from yellowing of the polyester. Meanwhile, nano-TiO.sub.2(B) is polymerized in situ in the polyester, such that a structure of nano-TiO.sub.2(B) can adjust the structure and properties of a polyester matrix and effectively improve the mechanical, thermal, and barrier properties of the polyester.

The present disclosure provides a honeycomb catalyst for catalytic oxidative degradation of VOCs prepared by an ultrasonic double-atomization process. The honeycomb catalyst is prepared by performing acidification and performing hydrothermal activation in alcoholic solution for honeycomb to modify a surface; dissolving soluble transition metal inorganic salt in deionized water to obtain precursor solution; performing ultrasonic atomization of the precursor solution and the precipitant solution in the ultrasonic atomization device into droplets; placing the modified honeycomb in a special quartz glass reactor, wherein the droplets enter into the quartz glass reactor through a pipeline to come into contact with a surface of a honeycomb hole and rapidly react to generate a hydroxide precursor on the surface of the honeycomb hole; drying the honeycomb into a drying box after performing the ultrasonic atomization, and calcining the honeycomb into a muffle furnace to obtain the honeycomb catalyst loaded with transition metal oxides.

An embodiment of the present specification provides a method for preparing a catalyst for preparing a carbon nanotube, comprising: (a) dissolving a main catalyst precursor, a support precursor, a cocatalyst precursor and a precipitation inhibitor in a solvent to prepare a precursor solution; and (b) pyrolyzing the precursor solution by spraying the precursor solution into a reactor, wherein a mole fraction of the precipitation inhibitor to the cocatalyst precursor is 0.1 to 1.5.

There are provided an easily producible catalyst particle-holding structure used for production of carbon nanotubes, and a method for producing the same. The method for producing the catalyst particle-holding structure of the present invention used for production of carbon nanotubes includes a step of forming a catalyst particle forming layer containing Si, Al, and Fe, and a step of performing a heat treatment on the catalyst particle forming layer in an atmosphere containing oxygen, to form catalyst particles containing Fe. The catalyst particles are held by the catalyst particle forming layer so that the catalyst particles are partially embedded in the catalyst particle forming layer. The size and the number of the catalyst particles containing Fe are controlled by adjusting the amount of oxygen contained in the atmosphere for the heat treatment. Thus, the catalyst particle-holding structure is formed easily.