Abstract: The present invention relates to a core-shell composite catalyst, wherein the core is a spinel-structure XYaOb catalyst, wherein X and Y, being different from each other, are metal elements selected from main group II, transition elements and main group III of the Periodic Table of Elements; a is a number between 1-15, preferably between 1-5; b is the number of oxygen atoms required to satisfy the valence of the elements; the shell is a molecular sieve catalyst, preferably selected from one or more of ZSM-5, ZSM-11, ZSM-35 and MOR, more preferably selected from ZSM-5 and ZSM-11. When the core-shell composite catalyst is used for preparing p-xylene directly from syngas in one step, the process is simple and easy to operate; the selectivity toward p-xylene in xylene products is high; the conversion of syngas is high; and the service life of the catalyst is long.

Abstract: The present invention relates to an alkali metal silicate coating formed from alkali metal silicate represented by the chemical formula M2O.nSiO2 and lithium silicate represented by the chemical formula Li2O.mSiO2, wherein M is selected from sodium, potassium, or a mixture thereof, n is from 2.9 to 3.7, m is from 4.2 to 4.8, and the molar ratio of M2O.nSiO2 to Li2O.mSiO2 is from 2.2 to 4.8; wherein the alkali metal silicate coating has a thickness of from 630 to 1,450 mg/m2, preferably from 700 to 1,400 mg/m2, in terms of SiO2 as measured by fluorescent X-ray spectrometry. The present invention further relates to a preparation method of the coating. The coating of the present invention has excellent heat resistance, hot water resistance and stain resistance, as well as excellent damage resistance.