الفهرس 
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Abstract
Al doped ZnO, Bi doped ZnO, and (Al-Bi) co-doped ZnO NPs were synthesized by co-precipitation of zinc nitrate, aluminum nitrate, and bismuth nitrate together in mole % of 1, 3, 5, and 7 by ammonia solution at pH 8, then calcined at 400 °C. The synthesized NPs were characterized by XRD, TEM, SEM, ICP-AES, EDS, BET, and UV-vis spectrophotometry. The photocatalytic activity of the doped ZnO NPs was investigated by photocatalytic degradation of Congo Red. All NPs had only the hexagonal Wurtzite crystal structure, except BZO included a secondary phase of -Bi2O3, which is due to the sparse solubility of Bi as a p-type dopant in ZnO. TEM and SEM images show that each family of the dopants take a specific trend of morphologies different from the plain ZnO. ICP-EAS and EDS show that all applied molar ratios entered into the precipitated crystal, except Bi, which was less than the started mole%. BET indicated almost unchanged specific surface area, although the doped NPs had different sizes than the plain ZnO. All doped ZnO NPs had red-shifted band gaps in the ascending order BZO<AZO<ABZO. However, the rate of their photocatalytic degradation to CR had the descending order ABZO>AZO>BZO, which we attribute to the enhanced Bi solubility in ZnO by co-doping with Al and formation of the acceptor-donor complex of more charge, less crystal deformations, lower recombination rate and more charge carrier mobility. Unlike BZO, which experiences remarkable crystal defects due to doping with Bi of the relatively large ionic radius and high valence.