Silver Carbonate-Silver-Tungsten Trioxide Ternary Composite Z-type Photocatalyst

The application of semiconductor photocatalyst in the degradation of toxic and harmful organic pollutants is of great significance for solving environmental pollution. However, broadband gap and low quantum efficiency are still the "bottlenecks" of photocatalysts. Therefore, the development of semiconductor heterojunctions is also an effective way to solve these problems, which can expand the spectral range of light absorption and inhibit the recombination of photoelectrons and holes.

Some researchers have designed a silver carbonate-silver-tungsten trioxide ternary composite Z-type photocatalyst, which has the advantages of high hole separation efficiency, high photocatalytic activity, strong redox ability, good stability and corrosion resistance. The catalytic steps of this material are as follows:

(1)The dilute nitric acid solution was obtained by adding 5 mL dense nitric acid droplets with 65% mass fraction into 25 mL deionized water under stirring conditions, stirring for 10 minutes; then the dilute nitric acid solution was mixed with 10 mL Na₂WO₄·2H₂O solution (containing 1.5 mmol Na₂WO₄·2H₂O) to form a light yellow solution, and stirred for 1 hour to obtain the slurry; finally, the slurry was transferred to a 50 mL stainless steel autoclave. The tungsten trioxide nanosheets were prepared by hydrothermal reaction at 180 C for 3 hours, after cooling, centrifugation, deionized water and ethanol cleaning, drying, and named WO₃.

(2)The tungsten trioxide nanosheets in step (1) of 305.5 mg were dispersed in 15 mL deionized water by ultrasound for 0.5 h to obtain tungsten trioxide dispersion solution.

(3)50 mg silver nitrate was dissolved in 4 mL deionized water, then the obtained silver nitrate solution was added to the tungsten trioxide dispersion obtained by step (2) and agitated for 0.5 h under dark conditions to obtain Ag+WO₃ dispersion.

(4)The Ag+WO₃ dispersion was prepared by adding 5 mL sodium bicarbonate solution with a concentration of 0.05 mol/L drop by drop into step (3). After stirring for 2 hours, the silver carbonate-silver-tungsten trioxide ternary composite Z-type photocatalyst was obtained under xenon lamp with a light intensity of 100 mW.cm^2- for 10 minutes.

Silver carbonate-silver-tungsten trioxide ternary composite Z-type photocatalyst has the advantages of simple synthesis method, low cost of raw materials, less energy consumption, short time-consuming and easy control of conditions. It has high degradation efficiency of pollutants, and has good practical application prospects.

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