PREPARATION OF PALLADIUM-CHITOSAN HYDROSOL AND ITS CATALYTIC ACTIVITY IN COPPER PRECIPITATION REACTION
Rubrics: 1. CHEMISTRY
Authors:
1.
Udmurtskiy gosud. universitet
2.
Udmurt State University
Type:
Article
eLocation:
Status:
Published
Received:
04.08.2025
Accepted:
07.08.2025
Published:
07.08.2025
Language:
Russian
Keywords:
PALLADIUM, CHITOSAN, NANOPARTICLES, COPPER PRECIPITATION, CATALYSIS
Abstract (English):
The results of a study of a new method for obtaining a colloidal solution containing metallic palladium nanoparticles are presented. Pd(II) ions were reduced from a H2PdCl4solution at room temperature in the presence of chitosan biopolymer (C₆H₁₁O₄N)n (n ≈3100, degree of deacylation 90%) using sodium hypophosphite NaH₂PO₂. The process was monitored using spectrophotometry for the formation of a broad plasmon resonance band of metallic palladium nanoparticles. Optimum conditions for rapid (5-10 min) formation of stable hydrosol were achieved at the ratio Pd: C₆H₁₁O₄N = 1:90 and excess of reducing agent (NaH₂PO₂: Pd>20). When there is a deficiency of chitosan in the solutions, palladium black precipitate is formed. The obtained solutions remain stable for more than 30 days at room temperature and withstand heating to 80°C. Analysis of the IR spectra in the region of vibrations of amino groups of chitosan confirmed that the interaction of Pd(II) with chitosan occurs via electrostatic mechanism involving protonated NH3+ groups of chitosan and anionic [PdCl4] 2-. The catalytic activity of palladium hydrosol was demonstrated in the reaction of Cu(II) reduction to metal. When adding a catalyst at a ratio of Cu(II) : Pd = 2000: 1, the degree of precipitation of powdered copper in 20 minutes at 80°C reached 90%. The mechanism of catalysis involves activation of the hypophosphite ion on the palladium surface with subsequent transition of the process to the autocatalytic mode. The high catalytic activity of the obtained colloidal palladium solutions makes them promising for use in chemical copper plating processes.
The results of a study of a new method for obtaining a colloidal solution containing metallic palladium nanoparticles are presented. Pd(II) ions were reduced from a H2PdCl4solution at room temperature in the presence of chitosan biopolymer (C₆H₁₁O₄N)n (n ≈3100, degree of deacylation 90%) using sodium hypophosphite NaH₂PO₂. The process was monitored using spectrophotometry for the formation of a broad plasmon resonance band of metallic palladium nanoparticles. Optimum conditions for rapid (5-10 min) formation of stable hydrosol were achieved at the ratio Pd: C₆H₁₁O₄N = 1:90 and excess of reducing agent (NaH₂PO₂: Pd>20). When there is a deficiency of chitosan in the solutions, palladium black precipitate is formed. The obtained solutions remain stable for more than 30 days at room temperature and withstand heating to 80°C. Analysis of the IR spectra in the region of vibrations of amino groups of chitosan confirmed that the interaction of Pd(II) with chitosan occurs via electrostatic mechanism involving protonated NH3+ groups of chitosan and anionic [PdCl4] 2-. The catalytic activity of palladium hydrosol was demonstrated in the reaction of Cu(II) reduction to metal. When adding a catalyst at a ratio of Cu(II) : Pd = 2000: 1, the degree of precipitation of powdered copper in 20 minutes at 80°C reached 90%. The mechanism of catalysis involves activation of the hypophosphite ion on the palladium surface with subsequent transition of the process to the autocatalytic mode. The high catalytic activity of the obtained colloidal palladium solutions makes them promising for use in chemical copper plating processes.
Keywords:
PALLADIUM, CHITOSAN, NANOPARTICLES, COPPER PRECIPITATION, CATALYSIS
PALLADIUM, CHITOSAN, NANOPARTICLES, COPPER PRECIPITATION, CATALYSIS
