Nano spinel NiAl₂O₄: structure, optical and photocatalytic performance evaluation and optimization

Area of Science:

• Materials Science
• Nanotechnology
• Environmental Chemistry

Background:

• Spinel NiAl2O4 is a promising material for photocatalysis.
• Controlling synthesis parameters is crucial for optimizing material properties and performance.
• Impurities can significantly impact photocatalytic efficiency.

Purpose of the Study:

• To synthesize spinel NiAl2O4 using the polyacrylamide gel method.
• To investigate the influence of different aluminum and nickel salts on the material's structure, optical properties, and photocatalytic activity.
• To optimize experimental parameters for enhanced photocatalytic degradation of tetracycline hydrochloride.

Main Methods:

• Polyacrylamide gel method for spinel NiAl2O4 synthesis.
• Characterization techniques (e.g., XRD, optical spectroscopy) to analyze material structure and properties.
• Photocatalytic experiments, response surface methodology, and free radical verification to assess degradation efficiency and mechanism.

Main Results:

• Spinel NiAl2O4 synthesized with aluminum sulfate (Al2(SO4)3·18H2O) and nickel sulfate hexahydrate (NiSO4·6H2O) showed no NiO impurity and exhibited higher photocatalytic activity.
• The presence of NiO and C-O functional groups, arising from using aluminum nitrate (Al(NO3)3·9H2O), inhibited photocatalytic activity.
• Optimized conditions (50 mg L-1 initial concentration, pH 5.33, 1 g L-1 catalyst) achieved 86.3% degradation of tetracycline hydrochloride.

Conclusions:

• The choice of aluminum salt significantly affects the purity and photocatalytic performance of spinel NiAl2O4.
• The polyacrylamide gel method is effective for synthesizing high-performance spinel NiAl2O4 photocatalysts.
• C-O functional groups can act as impurity levels and influence electron transfer, impacting degradation efficiency.