Activated metal Bi and La modified SAPO-34 molecular sieve and its photocatalytic degradation of formaldehyde in aqueous solution

As a new type of photocatalyst, molecular sieve photocatalysts have shown a promising future in the degradation of organic matter in water bodies. In this paper, a new type of molecular sieve photocatalyst was successfully prepared by introducing Bi and La elements into the hydrothermal synthesis of SAPO-34 molecular sieve for the purpose of regulating the molecular sieve backbone. The introduction of active metals into the skeleton of molecular sieve can enrich the Lewis acids acid sites on its surface. At the same time, the introduction of active metals can accelerate the transition rate of photogenerated carriers, which can also suppress the compound rate of electron holes. Under the action of 500w mercury lamp, the degradation rate of 20 ml 0.5 mg/mL formaldehyde solution was 77.61% in 6 h. Meanwhile, the degradation rate constant k could reach 0.3222 min−1, indicating that the photocatalytic degradation of formaldehyde showed excellent performance. This study provides a new method for the preparation of molecular sieve photocatalysts and a new idea for the construction of bifunctional photocatalysts.