## 1 Introduction
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**NC/NC/NC/NC/Sine (nm)** & **Polultants** & **Reaction Conditions** & **Removal** \\
**Reference** & **Efficiency (\%)** & **Efficiency (\%)** \\ \hline \multicolumn{4}{c}{_Heterogeneous photostatalysis_} \\ \hline TiO, & Phenol (\(500\pm 7\) mg/(1), super oil and grease (SOC) & \(8\,\mathrm{g}/\mathrm{L}\) of catalyst, auction flow rate of 1.225 L/min, & 76\% of phenol and 88\% of SOC \\ \hline O(nm)[17] & (\(400\pm 2\) mg/(1) and oil refrigerator) wastewater & \(200\) mg/(L of catalyst, solar irradiation) & 57\% \\ \hline TiO, & Ardenighment & \(200\) mg/(L of catalyst, solar irradiation) & 57\% \\ (443-48-0 nm) [18] & (\(0.5\) mg/(L) & \(100\) mg/(L), \(200\) mg/(L) & \(57\%\) \\ \hline \multirow{2}{*}{Hierarchically structured-to-ISO shallow nanocatalyst} & Pritchanum delivery wastewater & pH7.5, 1.649 g/L of catalyst, pH3, COPD ratio of & \\  & COD 127 mg/L & \(1\) mg/mg/(L)-AMP solar irradiation, & 90.85\% of COPD \\ \hline \multirow{2}{*}{ZnO or NO[20]} & Anthracome & pH7.25, 55 mg/(L of catalyst, emulsion & 90\% with ZnO and 87\% with NiO for anthracene \\  & (\(01.8\) mg/(L) & solution–\(200\) min, anthracaceous aqueous ethanol solution & 55\% with ZnO and 86\% with \\  & Zo@ nanorods & & & \\  & Zo@ nanorods & & & \\  & & & & \\  & & & &  
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The crystal structure of the catalyst plays an important role in the efficiency of its functioning. Compared to a bulk-size CuS catalyst, hierarchically structured CuS hollow nanocatalyst HS-CuS-HNCs with a narrower band gap (Eg = 0.96 eV) exhibited characteristics of strong visible light absorption, highly enhanced quantum efficiency and large specific area (101.5 m\({}^{2}\)/g). HS-CuS-HNCs showed significantly enhanced activity for the degradation of pollutants under both artificial and real solar light sources. About 66% of COD in PRW was removed in 3 h within the degradation process in the presence of a 1.0 g/L nanocatalyst and pH 7.6 [15]. NComs, in comparison with NCs, show higher activity due to their increased active surface area. Activated carbon, graphite carbonitrides g-C\({}_{3}\)N\({}_{4}\), Bi\({}_{2}\)WO\({}_{6}\), three-dimensional graphene gels, MOFs and others are tested as carriers for obtaining NComs, with the possibility of loading a large number of NCs. A tendency to increase the efficiency of degradation of pollutants was revealed for NComs such as TiO\({}_{2}\)@ZnHCF compared with TiO\({}_{2}\)[23], and for activated carbon-supported copper (II) oxide CuO/AC, better results were found in comparison with CuO [29]. MOFs and their derivatives become an integral part of heterogeneous catalysts in the mineralization of organic substances due to their large specific surface area, large number of active centers and simplicity of structural regulation [25; 30]. When combining different AOPs, a synergistic effect can be expected. The activity of hierarchically structured CuS hollow nanocatalyst HS-CuS-HNCs was drastically enhanced further in the presence of hydrogen peroxide (H\({}_{2}\)O\({}_{2}\)) (98% of COD was removed in 2 h in PRW in the presence of 1.0 g/L catalyst, 3.0 g/L H\({}_{2}\)O\({}_{2}\) and pH 7.6). This was attributed to the synergistic effect between HS-Cs-Hns and H\({}_{2}\)O\({}_{2}\), leading to the enhanced quantum efficiency and production of more reactive oxygen species [15]. The highest efficiency (89.58-98%) of wastewater cleaning with minimal time (0.5-2 h) is observed when combinations of NCs are used [15; 30; 31; 32]. An increase in the concentration of the oxidants and the doses of NCs are expected to increase the efficiency of removing organic pollutants [37; 38]. In the course of wastewater treatment from organic pollutants, the presence of some cations and anions in the medium in combination with the oxidizer used and a certain structure plays an important role. The salinity of water (1-4% NaCl) had practically no effect on the efficiency of photocatalytic decomposition of phenolic derivatives with ZnO nanorods.