# Nanomaterials in Photocatalysis: An In-Depth Analysis of Their Role in Enhancing Indoor Air Quality
## 10 Perovskite Nanomaterials  
The study of perovskite materials for photocatalysis began gaining significant attention in the early 2000s, but the broader interest in perovskites dates back to their discovery in the 19 th century and their initial use in electronic and optical applications in the 20 th century. The turning point for perovskites in photocatalysis occurred after 2010, following the surge of interest in perovskite-based solar cells. Research into perovskites for photocatalysis began with studies of metal oxide-based perovskites, such as barium titanate (BaTiO\({}_{3}\)) and strontium titanate (SrTiO\({}_{3}\)). These materials demonstrated potential for applications like water splitting and pollutant degradation, though their UV-light activation limited broader applications. The breakthrough in hybrid perovskite materials like methylammonium lead halides (e.g., CH\({}_{3}\)NH\({}_{3}\)PbI\({}_{3}\)) for solar cells sparked an explosion of research into their optical and electronic properties. Soon after, their potential for photocatalysis, particularly under visible light, was explored. In the mid-2010s, researchers began optimizing perovskite materials for photocatalytic applications, focusing on improving their stability, charge carrier dynamics, and scalability. This period also saw the exploration of lead-free and fully inorganic perovskites to address toxicity and stability challenges. Perovskite photocatalytic nanomaterials have emerged as an innovative class of materials in the field of photocatalysis, particularly due to their unique crystal structure, which enables remarkable light absorption and efficient charge carrier dynamics. These materials, characterized by the general formula ABX\({}_{3}\), where A and B are cations and X represents an \begin{table}
\begin{tabular}{c c c c} \hline \hline
**MOF Name** & **Structure** & **Applications** & **References** \\ \hline MOF-5 & \begin{tabular}{c} Composed of zinc oxide clusters and \\ terephthalate linkers \\ \end{tabular} & Photocatalytic degradation of organic pollutants & [213] \\ ZIF-8 & \begin{tabular}{c} Zinc imidazoline framework with a \\ sodalite topology \\ \end{tabular} & CO\({}_{2}\) conversion, degradation of pollutants & [214; 215; 216] \\ MIL-125 & \begin{tabular}{c} Titanium-based framework with a \\ paddle-wheel structure \\ \end{tabular} & Photocatalytic degradation of dyes and pollutants & [217; 218] \\ UiO-66 & \begin{tabular}{c} Zirconium-based with a \\ octahedral topology \\ \end{tabular} & Photocatalytic degradation of dyes and pollutants & [219] \\ NH2-MIL-125 & Amino-functionalized variant of MIL-125 & Photocatalytic degradation of dyes and pollutants & [220; 221] \\ ZIF-67 & \begin{tabular}{c} Cobalt imidazolate framework \\ \end{tabular} & Photocatalytic degradation of dyes and pollutants & [222; 223] \\ MOF-808 & \begin{tabular}{c} Zirconium-based with a fcu topology \\ \end{tabular} & Photocatalytic CO\({}_{2}\) & [224; 225] \\  & \begin{tabular}{c} The MIL-53 structure consists of \\ inorganic [M-OH] chains, which are \\ \end{tabular} & \begin{tabular}{c} Photocatalytic degradation of dyes and pollutants \\ \end{tabular} & [226; 227; 228] \\ MIL-53 & \
\begin{tabular}{c} connected to four neighboring inorganic \\ chains by therephthalate-based \\ linker molecules \\ \end{tabular} & Photocatalytic degradation of dyes and pollutants & [226; 228; 227] \\ Cu-BTC &
\begin{tabular}{c} Copper-based with a \\ three-dimensional structure \\ \end{tabular} & Photocatalytic degradation of pollutants & [229] \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Common MOF in photocatalysis, structures, and examples of their applications. anion, can be composed of a variety of elements, allowing for tunable properties and enhanced photocatalytic performance. Perovskites can exist in both organic-inorganic hybrid forms and fully inorganic forms, with notable examples including methylammonium lead halides (MAPbX\({}_{3}\)) [230] and barium titanate (BaTiO\({}_{3}\)) [231].