Preparation Of Bimetallic Functional Nanomaterials And Their Applications For Catalysis And Colorimetric Detection

Bimetallic nanocatalysts have attracted more attentions in the fields of environment,medicine,new energy and various chemical products due to their unique optical properties,excellent stability,activity and synergistic effect.Noble metals such as Ag and Au have received great attention because of their good stability and excellent catalytic efficiency.In this paper,bimetallic catalysts based on Au and Ag were designed and prepared,which were respectively applied to the catalytic reduction of 4-nitrophenol and the colorimetric detection of serum glutathione according to their different catalytic properties in practical samples.The main contents are as follows:Part 1:Low-Ag-content Ni₃N-Ni/Ag@C catalyst for the reduction of 4-nitrophenol.It is promising for the treatment of contaminated water to find an effective,easy synthesis,stability,long-life,affordable catalyst with a low level of noble metals.This resulted in the development of a novel catalyst for the catalytic reduction of 4-nitrophenol（4-NP）in the presence of Na BH₄ with a low Ag concentration（0.6 wt%）.At 380°C annealing,Ni₃N-Ni heterostructures were embedded in a carbon matrix using the urea-glass method,and then Ag nanoparticles were added to the Ni₃N-Ni@C by galvanically replacing Ag NO₃ with Ni.Ni₃N-Ni/Ag（0.6 wt%）@C demonstrated excellent catalytic activity and stability toward 4-NP reduction,with a rate constant normalised by Ag mass of 8.1×10³ s^-1g_Ag^-1.The effects of inorganic and organic species on the catalytic efficiency were further tested and they demonstrated negligible impacts.Lake water contaminated with highly concentrated 4-NP（140 ppm）could be rapidly purified by the catalyst within 6 min.This research paves a new path to synthesise low-cost and efficient catalysts for the treatment of water contamination.Part 2:Dendritic Au Cu alloy as a nanozyme for colorimetric detection of glutathione in serum.Colorimetric biological analysis has attracted wide attention due to its simplicity and high sensitivity.In this work,dendritic Au Cu alloy nanomaterials were rapidly prepared by galvanic displacement reaction at room temperature.The alloy was proved to be a nanoenzyme based on its characteristic Michaelis-Menten equation.Au Cu alloyed nanoenzyme was used to oxidize colourless tetramethylbenzidine（TMB）into blue oxide TMB（ox-TMB）in the presence of H₂O₂.Meanwhile,since glutathione（GSH）played an inhibiting effect in the oxidation of TMB,Au Cu alloyed nanoenzyme was further used for colorimetric detection of GSH with the linear range of 0.04～16.67μM and limit of detection of 40 n M.The detection of GSH in human serum was performed,holding the standard recoveries in the range of 96.5%～108.0%.It is expected to achieve rapid and sensitive detection of low concentration GSH in complex systems.The preparation of the artificial nanoenzyme is simple and low-cost,pushing great application potential in routine blood detection.