An emerging photocatalyst for wastewater remediation: a mini-review on CaCu₃Ti₄O₁₂ photocatalysis

Ceramics-based filter for water treatment is an ancient technology to procure potable water at the household level. The traditional clay pots (vessels or hollow cylindrical container) have been used since long in the developing countries. The ceramic material (CaCu₃Ti₄O₁₂ or CCTO) is a hetero-junction of titanium oxide, a well-known UV-active photocatalyst, and visible light absorbing CuO materials. This hetero-junction is able to overcome the limitations such as high bandgap, poor stability, low efficiency, and high photo-generated charge (e^-/h⁺) recombination rate, associated with the other commonly used metal oxide semiconductor photocatalysts. Moreover, the low-cost, viable and facile synthesis routes for CCTO triggered its potential applications in photoelectrochemical and photocatalytic processes. This review will elaborate on the available literature demonstrating the visible light activity of CCTO photocatalysts in water treatment technologies. Furthermore, the mechanism of photocatalysis and synthesis routes are presented in this work for broader impact of the CCTO potential applications. The extended porous character and excellent surface texture have made the ceramic materials as an ideal choice to combat the bacteria, pathogens and turbidity in aqueous medium at household level. Specifically, the controlled size and shape make the CaCu₃Ti₄O₁₂ (CCTO) an excellent visible light-driven photocatalyst, involving highly reactive species such as ^•OH, ^•O₂^- anions, h⁺, and e^-, for the removal of organic and inorganic pollutants from water.