CuAl Hydrotalcite Formed CuAl‐Mixed Metal Oxides for Photocatalytic Removal of Rhodamine B and Cr(VI)

Abstract Mixed metal oxides (MMOs) are important semiconductor photocatalysts for water treatment, such as removal of organic dyes and metal ions. In this paper, CuAl hydrotalcite‐like compounds (CuAl‐HTLcs) were synthesized by the coprecipitation method using Al(NO 3 ) 3 ⋅9H 2 O and Cu (NO 3 ) 2 ⋅3H 2 O as raw materials. Cu 2 O/Cu 2 Al 2 O 4 mixed metal oxides (MMO) were prepared by calcining CuAl‐HTLcs at 900 °C. The obtained composites were characterized by various methods, including X‐ray diffraction (XRD), Scanning electron microscopy (SEM), and UV‐Vis diffuse reflectance spectroscopy (DRS), among others. Their photocatalytic activities towards removal of Rhodamine B (RhB) and Cr(VI) were evaluated by spectrophotometry, XRD revealed that CuAl‐MMO composites were composed of high crystallinity Cu 2 O and Cu 2 Al 2 O 4 grains. DRS showed the strong ultraviolet absorption ability of the composites. The electrochemical testing demonstrated CuAl‐MMO composites with good photocatalytic activities towards the removal of Rhodamine B (RhB) and Cr(VI) under ultraviolet light, with reaction rate constants determined as 0.41 h −1 and 0.49 h −1 , respectively. The relevant photocatalytic activities of CuAl‐MMO composites were attributed to the synergy between the two components. Overall, these data look promising for future use of CuAl‐MMO as an important photocatalyst for water remediation.