【摘要】 以AgNO₃和HAuCl₄为前驱体，以羧甲基壳聚糖（CMC）同时为还原剂和稳定剂制备了金银合金纳米粒子（Au-Ag ANPs）,研究了反应温度、时间、NaOH和CMC浓度的影响。通过紫外-可见吸收光谱（UV-Vis）、透射电子显微镜（TEM）、傅里叶变换红外光谱（FT-IR）和X-射线衍射（XRD）对Au-Ag ANPs进行了表征。考察了Ag_0.5Au_0.5投加量、4-NP/NaBH₄摩尔比、反应温度和不同条件下制备的Au-Ag ANPs对水溶液中4-硝基苯酚（4-NP）的催化还原性能的影响。结果表明：通过控制Au-Ag ANPs制备时AgNO₃和HAuCl₄的体积比(V_AgNO3/V_HAuCl4)即可灵活调整Au-Ag ANPs中Au、Ag元素的含量。相同V_AgNO3/V_HAuCl4时，NaOH和CMC浓度也会影响Au-Ag ANPs中Au、Ag元素的含量。Au-Ag ANPs的平均粒径在（4.5±1.2）nm(Ag_0.8Au_0.2)至（6.5±1.3）nm(Ag_0.2Au_0.8)之间，均小于AuNPs[（16.8±3.7）nm]和AgNPs[（11.7±1.4）nm]的平均粒径。不同Au、Ag元素含量的Au-Ag ANPs对4-NP的催化还原活性均大于AuNPs和AgNPs。在30℃,催化剂投加量60μL,4-NP/NaBH₄=1/500时，催化反应30min, Au_0.6Ag_0.4对4-NP的转化率为91.1%,反应速率常数为0.1289min^-1。更多还原

【Abstract】 Gold-silver alloy nanoparticles（Au-Ag ANPs） were synthesized with AgNO₃ and HAuCl₄ as precursors and carboxymethyl chitosan（CMC） as both reducing agent and stabilizer.The effects of reaction temperature, time, NaOH and CMC concentration on the properties of the Au-Ag ANPs were studied.Au-Ag ANPs were characterized by ultraviolet-visible absorption spectroscopy（UV-Vis）,transmission electron microscopy（TEM）,Fourier transform infrared spectroscopy（FT-IR） and X-ray diffraction（XRD）.The effects of Ag_0.5Au_0.5 dosage, 4-NP/NaBH₄ molar ratio, reaction temperature and the different synthesis conditions of Au-Ag ANPs on the catalytic reduction performance of 4-nitrophenol（4-NP） in aqueous solution were investigated.The results showed that the contents of Au and Ag elements in Au-Ag ANPs could be flexibly adjusted by controlling the volume ratio of AgNO₃ and HAuCl₄(V_AgNO3/V_HAuCl4) during the synthesis of Au-Ag ANPs.When V_AgNO3/V_HAuCl4 was the same, the concentration of NaOH and CMC also affected the contents of Au and Ag elements in Au-Ag ANPs.The average particle size of Au-Ag ANPs ranged from（4.5±1.2）nm(Ag_0.8Au_0.2) to（6.5±1.3）nm(Ag_0.2Au_0.8),which was smaller than that of AuNPs（16.8±3.7nm） and AgNPs（11.7±1.4nm）.The catalytic reduction activities of Au-Ag ANPs with different Au and Ag contents on 4-NP waere higher than those of AuNPs and AgNPs.The catalytic reaction was performed for 30 min at 30℃ with a catalyst dosage of 60μL and 4-NP/NaBH₄ of 1/500,and the conversion rate of Au_0.6Ag_0.4 to 4-NP was 91.1% and the reaction rate constant was 0.1289min^-1.更多还原