Silica-coated silver core composite particles and their preparation method and use

[0052] 1) Pour 100ml of dehydrated ethanol with a density of 0.791g / ml into a 500ml large beaker that has been washed and dried in advance, add water to dilute to an aqueous ethanol solution containing 50% ethanol by mass, and mix the nitric acid with stirring Add 5.0ml of silver nitrate aqueous solution with a silver concentration of 0.10mol / L dropwise into an ethanol aqueous solution with a mass percentage of 50% ethanol to obtain a mixed solution, heat the mixed solution to 80°C, and then add polyvinylpyrrolidone after the temperature is stable Aqueous solution (containing 2g of polyvinylpyrrolidone, using polyvinylpyrrolidone of type K30 produced by BASF Company in Germany) 20mL, then dropwise added 5.0ml of aqueous sodium hydroxide solution with a sodium hydroxide concentration of 0.10mol / L, reacted at 80°C for 2h, After cooling down to 25°C, a solution containing silver nanoparticles is obtained;

[0053] 2) Under stirring conditions, add 5.0ml of ammoniacal liquor co

[0062] 1) Pour 100ml of dehydrated ethanol with a density of 0.791g / ml into a 500ml large beaker that has been washed and dried in advance, add water to dilute to an aqueous ethanol solution containing 40% ethanol by mass, and mix the nitric acid with stirring Add 5.0ml of silver nitrate aqueous solution with a silver concentration of 0.10mol / L dropwise into an ethanol aqueous solution with a mass percentage of 40% ethanol to obtain a mixed solution, heat the mixed solution to 80°C, and then add polyvinylpyrrolidone after the temperature is stable Aqueous solution (containing 2g of polyvinylpyrrolidone, using polyvinylpyrrolidone of type K30 produced by Germany BASF company) 20mL, then add dropwise 5.0ml of aqueous sodium hydroxide solution with a concentration of sodium hydroxide of 0.10mol / L, and react at 90°C for 1.5h , after cooling down to 25°C, a solution containing silver nanoparticles is obtained;

[0063] 2) Under the condition of stirring, add 5.0ml of ammonia wat

[0067] 1) Pour 100ml of dehydrated ethanol with a density of 0.791g / ml into a 500ml large beaker that has been washed and dried in advance, add water to dilute it to an aqueous ethanol solution containing 60% ethanol by mass, and mix the nitric acid with stirring Add 5.0ml of silver nitrate aqueous solution with a silver concentration of 0.10mol / L dropwise into an aqueous ethanol solution containing 60% ethanol by mass to obtain a mixed solution, heat the mixed solution to 70°C, and then add polyvinylpyrrolidone after the temperature is stable Aqueous solution (containing 2g of polyvinylpyrrolidone, using polyvinylpyrrolidone of type K30 produced by BASF, Germany) 20mL, then dropwise added 5.0ml of aqueous sodium hydroxide solution with a sodium hydroxide concentration of 0.10mol / L, reacted at 70°C for 3h, After cooling down to 25°C, a solution containing silver nanoparticles is obtained;

[0068] 2) Under stirring conditions, add 5.0ml of ammonia water containing 0.91g of