Preparation method for synthesizing Cu-SAPO-34 molecular sieve based catalyst through hydrogen fluoride modified one-step method

The invention provides a preparation method for synthesizing a Cu-SAPO-34 molecular sieve based catalyst through a hydrogen fluoride modified one-step method. The method comprises the steps that an aluminum source, orthophosphoric acid, a silicon source, copper sulfate, tetraethylenepentamine and hydrogen fluoride are sequentially added to deionized water to be fully stirred, gel is obtained and placed in a hydrothermal reaction kettle, reacting is carried out for 0.5-5 days at the temperature of 150 DEG C to 200 DEG C, and after cooling, filtering, washing and drying are carried out, calcination is carried out at the temperature of 550 DEG C to obtain the Cu-SAPO-34 molecular sieve based catalyst. Cu-SAPO-34 is synthesized in situ through the hydrogen fluoride modified one-step method, the degree of crystallinity of a molecular sieve is improved, SAPO-5 and other mixed crystals are prevented from being generated, the crystallization speed of the molecular sieve is increased, crystallization time is only 1/2-1/3 that of a molecular sieve without hydrogen fluoride, structure defect sites are reduced, the acid site density of the molecular sieve is increased, an NH3-SCR temperature window of the catalyst is widened, and the hydrothermal stability performance of the catalyst is improved.