The performance and function of the active alumina catalyst: This product is a white, spherical, porous material; odorless, non-friable, and insoluble in water and ethanol. The white spherical material is produced through a special process and, due to its unique skeletal structure, has a strong affinity with the active components. The product features a uniform distribution of micropores, suitable pore size, large pore volume, high water adsorption rate, low bulk density, and good mechanical properties, offering excellent stability. It is suitable for use as a catalyst carrier. The Co-Mo series sulfur-tolerant shift catalysts prepared with this product exhibit good low-temperature activity, a broad operating temperature range, and short sulfurization time, making them ideal for medium and small ammonia synthesis plants.