3D-macroporous chitosan-based scaffolds (cryogels) were produced via growth of metal-polymer coordinated complexes and electrostatic interactions between oppositely charged groups of chitosan and metal ions under subzero temperatures. A mechanism of reduction of noble metal complexes inside the cryogel walls by glutaraldehyde is proposed, which produces discrete and dispersed noble metal nanoparticles. 3D-macroporous scaffolds prepared under different conditions were characterised using TGA, FTIR, nitrogen adsorption, SEM, EDX and TEM, and the distribution of platinum nanoparticles (PtNPs) and palladium nanoparticles (PdNPs) in the material assessed. The catalytic activity of the in situ synthesised PdNPs, at 2.6, 12.5 and 21.0 μg total mass, respectively, was studied utilising a model system of 4-nitrophenol reduction. The kinetics of the reaction under different conditions (temperature, concentration of catalyst) were examined, and a decrease of catalytic activity was not observed over 17 treatment cycles. Increasing the temperature of the catalytic reaction from 10 to 22 and 35 ͦC by PdNPs supported within the cryogel increased the kinetic rate by 44 and 126%, respectively. Turnover number and turnover frequency of the PdNPs catalysts at room temperature were in the range 0.20 − 0.53 h⁻¹. The conversion degree of 4-nitrophenol at room temperature reached 98.9% (21.0 μg PdNPs). Significantly less mass of palladium nanoparticles (by 30-40 times) was needed compared to published data to obtain comparable rates of reduction of 4-nitrophenol.

通过在零度以下温度下金属-聚合物配位复合物的生长以及壳聚糖和金属离子的带相反电荷的基团之间的静电相互作用，生成了基于3D-大分子壳聚糖的支架（cryogels）。提出了戊二醛还原冷冻凝胶壁内贵金属络合物的机理，该机理可产生离散的和分散的贵金属纳米颗粒。使用TGA，FTIR，氮吸附，SEM，EDX和TEM以及在所评估材料中铂纳米颗粒（PtNPs）和钯纳米颗粒（PdNPs）的分布，对在不同条件下制备的3D大型支架进行了表征。原位催化活性利用4-硝基苯酚还原模型系统研究了合成的PdNP，分别为2.6、12.5和21.0μg。检查了在不同条件（温度，催化剂浓度）下反应的动力学，在17个处理周期中未观察到催化活性的降低。冷冻凝胶中负载的PdNP将催化反应的温度从10°C升高到22°C和35°C，动力学速率分别提高了44％和126％。室温下PdNPs催化剂的周转数和周转频率在0.20-0.53 h ^-1的范围内。室温下4-硝基苯酚的转化率达到98.9％（21.0μgPdNPs）。与公布的数据相比，获得相当数量的4-硝基苯酚还原速率需要的钯纳米粒子质量要少得多（达30-40倍）。