Ag/SiO₂ colloidal nanocomposites (NCs) were synthesised by the chemical reduction of silver ions on a silica surface; NaBH₄ was used as a reducing agent, while chitosan served as a stabiliser. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) results of Ag/SiO₂ showed a high-density distribution of silver nanoparticles on the silica surface. The influence of pH, ionic concentrations on the stability of Ag/SiO₂ colloidal NCs was investigated. Ag/SiO₂ colloidal NCs were stable in a wide range of pH values (3–10) and the presence of cations (Mg²⁺ 25 mM, Ca²⁺ 15 mM, Fe²⁺ 1 mM, Fe³⁺ 0.8 mM). Furthermore, the antimicrobial activity of Ag/SiO₂ colloidal NCs against Ralstonia solanacearum 15 (R. solanacearum 15), Bipolaris oryzae (B. oryzae) was evaluated. The minimum inhibitory concentration (MIC) of Ag/SiO₂ colloidal NCs for R. solanacearum 15 was 10 ppm, two times lower than that of silver nanoparticles (AgNPs) at 20 ppm, which were prepared by the same route. The inhibitory rate of Ag/SiO₂ colloidal NCs against B. oryzae was 99.3% higher than the inhibitory rate of AgNPs 80.4% at the same Ag concentration of 32 ppm. Therefore, Ag/SiO₂ colloidal NCs with high antimicrobial activity and stability in wide range pH and ionic strength are a promising pesticide in agriculture.

Ag/SiO ₂胶体纳米复合材料（NCs）是通过银离子在二氧化硅表面的化学还原合成的；NaBH ₄用作还原剂，而壳聚糖用作稳定剂。Ag/SiO _{2 的}扫描电子显微镜(SEM) 和透射电子显微镜(TEM) 结果表明，银纳米颗粒在二氧化硅表面上具有高密度分布。研究了pH值、离子浓度对Ag/SiO ₂胶体NCs稳定性的影响。Ag/SiO ₂胶体 NCs 在很宽的 pH 值范围 (3–10) 和存在阳离子 (Mg ²⁺ 25 mM, Ca ²⁺ 15 mM, Fe ²⁺ 1 mM, Fe ³⁺0.8 毫米）。此外，还评估了 Ag/SiO ₂胶体 NCs 对青枯病菌15 (R. solanacearum 15)、米双极( B. oryzae )的抗菌活性。青枯菌 15的 Ag/SiO ₂胶体 NCs的最小抑菌浓度 (MIC)为 10 ppm，是通过相同途径制备的 20 ppm 银纳米粒子 (AgNPs) 的两倍。Ag/SiO ₂胶体NCs对米曲霉的抑制率比AgNPs 80.4%的抑制率高99.3%，Ag浓度为32 ppm。因此，Ag/SiO ₂ 在广泛的 pH 值和离子强度范围内具有高抗菌活性和稳定性的胶体 NCs 是一种很有前途的农业杀虫剂。