# Nanomaterials in Photocatalysis: An In-Depth Analysis of Their Role in Enhancing Indoor Air Quality
## 10 Perovskite Nanomaterials
The structure of perovskites facilitates efficient charge separation and transport, which minimizes recombination losses and enhances the overall photocatalytic activity. Furthermore, the tunability of perovskite materials allows for optimization of their bandgap, enabling them to effectively harness solar energy for various photocatalytic processes [232]. Perovskite photocatalytic nanomaterials have shown great potential in a range of applications (Table 5). One of the most significant is in the area of environmental remediation, where they can effectively degrade organic pollutants, including dyes and pharmaceuticals, through photocatalytic oxidation. Additionally, they are being actively researched for applications in hydrogen production through water splitting, offering an efficient pathway for solar-to-hydrogen conversion. The ability of perovskites to facilitate carbon dioxide reduction into valuable fuels and chemicals further highlights their versatility and potential impact in addressing energy sustainability and environmental challenges. With ongoing advancements in synthesis methods and material engineering, perovskite photocatalytic nanomaterials are poised to play a pivotal role in future photocatalytic applications. Perovskite materials exhibit excellent light-harvesting capabilities due to their tunable bandgap and high absorption coefficients, making them highly efficient under visible light. This gives them an advantage over traditional photocatalysts like TiO\({}_{2}\), which primarily rely on UV light for activation. The crystal structure of perovskites facilitates efficient charge separation and transport, reducing electron-hole recombination. This leads to enhanced photocatalytic activity compared to other materials with less efficient charge dynamics. Moreover, perovskites can be engineered with a wide variety of compositions (organic-inorganic hybrids, all-inorganic) to tailor properties such as bandgap, stability, and catalytic efficiency. This tunability is more versatile compared to fixed-structure materials like TiO\({}_{2}\) or ZnO. Many perovskites can be synthesized using relatively low-temperature and solution-based methods, making them more cost-effective and scalable compared to some metal oxide-based photocatalysts. One of the most significant drawbacks of perovskites, particularly hybrid organic-inorganic forms, is their susceptibility to degradation under environmental conditions such as moisture, UV light, and high temperatures. This is a critical limitation compared to more robust materials like TiO\({}_{2}\) and ZnO. Moreover, many high-performance perovskites, \begin{table}
\begin{tabular}{c c c c} \hline
**Perovskite Material** & **Structure** & **Applications** & **References** \\ \hline CH\({}_{3}\)NH\({}_{3}\)PbI\({}_{3}\) & Organomental halide perovskite with a cubic structure & CO\({}_{2}\) reduction & [233; 234] \\ CsPbBr\({}_{3}\) & Inorganic perovskite with a cubic lattice & Photocatalytic degradation of organic pollutants, CO\({}_{2}\) reduction & [235; 236] \\ MAPbBr\({}_{3}\) & Methylammonium lead bromide with a tetragonal structure & Photocatalytic CO\({}_{2}\) reduction, & [237; 238; 239] \\ Cs\({}_{2}\)AgBiBr\({}_{6}\) & Layered perovskite structure & Photocatalytic hydrogen production & [240] \\ BaTiO\({}_{3}\) & Classic perovskite structure & Photocatalytic degradation of pollutants, CO\({}_{2}\) reduction & [241; 242] \\ SrTiO\({}_{3}\) & Titanium-based perovskite & CO\({}_{2}\) reduction, degradation of pollutants & [243; 244; 245] \\ KTaO\({}_{3}\) & Potassium tantalate perovskite & Photocatalytic degradation of pollutants & [246; 247; 248] \\ LaTiO\({}_{3}\) & Lanthanum titanate perovskite & Photocatalytic degradation of pollutants & [249; 250] \\ MAPbI\({}_{3}\) & Doped organomental halide perovskite & Photocatalytic degradation of pollutants & [239; 251] \\ \hline \end{tabular}
\end{table} 
Table 5: Common perovskites in photocatalysis, structures, and examples of their applications.