▎ 摘　　要

NOVELTY - A catalyst comprises a first catalytic layer, an insulating layer and a second catalytic layer. The first catalytic layer is a metal oxide catalyst containing cupric oxide-zinc oxide-aluminum oxide-metal oxide composite (I). In the composite, the total weight of copper, zinc, aluminum and metal is calculated according to 100%, and the content of copper is 40-55%, content of zinc is 20-30%, content of aluminum is 4-8%, and the remainder is metal (M). The insulating layer is quartz sand. The second catalytic layer is a copper-based catalyst containing 5-12% copper, 0.5-2% additive and remaining carrier. The additive is at least one of potassium, magnesium, lanthanum or cerium, the carrier is graphene, carbon nanotubes or activated carbon, and the specific surface area of the carrier is more than 200 m2/g. USE - Catalyst used for preparing methyl formate from catalytic synthesis gas by one-step method (claimed). ADVANTAGE - The catalyst preparation method is simple and environmentally-friendly. The one-step synthesis of methyl formate from catalytic synthesis gas is realized under gas-solid phase conditions, and the reaction conditions are mild. DETAILED DESCRIPTION - A catalyst comprises a first catalytic layer, an insulating layer and a second catalytic layer. The first catalytic layer is a metal oxide catalyst containing cupric oxide-zinc oxide-aluminum oxide-metal oxide composite of formula: CuO-ZnO-Al2O3-MOx (I). In the composite, the total weight of copper, zinc, aluminum and metal is calculated according to 100%, and the content of copper is 40-55%, content of zinc is 20-30%, content of aluminum is 4-8%, and the remainder is metal (M), where M is at least one of cerium, zirconium, manganese and magnesium, and x is a number of oxygen atoms required to satisfy oxidation state of metal element. The insulating layer is quartz sand. The second catalytic layer is a copper-based catalyst containing 5-12% copper, 0.5-2% additive and remaining carrier. The additive is at least one of potassium, magnesium, lanthanum or cerium, the carrier is graphene, carbon nanotubes or activated carbon, and the specific surface area of the carrier is more than 200 m2/g. INDEPENDENT CLAIMS are included for: (1) preparation of the catalyst, which involves: (a) dripping salt solution of copper, zinc, aluminum, metal and precipitant solution to water at 60-90℃, and controlling pH value of the system to 7-9.5 by controlling dripping speed of the precipitant solution, and aging at 60-90℃ for 2 hours and washing, drying, roasting, tablet forming and sieving to obtain a metal oxide catalyst; (b) dissolving copper salt and auxiliary precursor in water or ethanol to form first solution, adding the carrier to first solution, ultrasonically processing for 0.5-2 hours, stirring at room temperature until there is no liquid in the container, drying, pressing into tablets, and sieving to obtain copper-based catalyst; and (c) taking the metal oxide catalyst to obtain first catalytic layer, weighing quartz sand to obtain insulating layer and weighing copper-based catalyst to obtain second catalytic layer; and (2) application of catalyst in preparation of methyl formate by one-step method of catalytic synthesis gas, which involves: (a) sequentially packing the second catalytic layer, insulating layer and first catalytic layer in the catalyst into fixed bed reactor in layers from bottom to top, introducing hydrogen-containing gas for reduction activation, adjusting the reaction temperature to 200-260℃, and switching the synthesis gas and increasing pressure to 0.5-2 MPa for the reaction.