Abatement of contaminants of emerging concerns (CECs) in water sources has been widely studied employing TiO₂ based heterogeneous photocatalysis. However, low quantum energy yield among other limitations of titania has led to its modification with other semiconductor materials for improved photocatalytic activity. In this work, a 0.05 wt.% CuWO₄ over TiO₂ was prepared as a powder composite. Each component part synthesized via the sol-gel method for TiO₂, and CuWO₄ by co-precipitation assisted hydrothermal method from precursor salts, underwent gentle mechanical agitation. Homogenization of the nanopowder precursors was performed by zirconia ball milling for 2 h. The final material was obtained after annealing at 500 °C for 3.5 h. Structural and morphological characterization of the synthesized material has been achieved employing X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) N₂ adsorption–desorption analysis, Scanning electron microscopy-coupled Energy dispersive X-ray spectroscopy (SEM-EDS), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis diffuse reflectance spectroscopy (UV-vis DRS) for optical characterization. The 0.05 wt.% CuWO₄-TiO₂ catalyst was investigated for its photocatalytic activity over carbamazepine (CBZ), achieving a degradation of almost 100% after 2 h irradiation. A comparison with pure TiO₂ prepared under those same conditions was made. The effect of pH, chemical scavengers, H₂O₂ as well as contaminant ion effects (anions, cations), and humic acid (HA) was investigated, and their related influences on the photocatalyst efficiency towards CBZ degradation highlighted accordingly.

Contaminants of emerging concerns (CECs) spread across a wide range of organic product compounds. As biorecalcitrants, their removal from conventional wastewater treatment systems remains a herculean task. To address this issue, heterogenous solar driven advanced oxidation process based-TiO₂ and other semiconductor materials has been extensively studied for their abatement from wastewater sources. In this study, we have synthesized by hydrothermal assisted co-precipitation Ag doped ZnSnO₃. Structural and morphological characterizations were performed via X-ray diffraction (XRD), Fourier transform infra-red (FTIR), N₂ adsorption-desorption at 77 K by Brunauer-Emmet-Teller (BET) and Barrett, Joyner, and Halenda (BJH) methods, Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy coupled with Energy dispersive spectroscopy (SEM-EDS), and UV-visible absorption in Diffuse reflectance spectroscopy (UV-vis/DRS) mode. Crystallite size estimate for Ag-ZnSnO₃ and undoped form was 19.4 and 29.3 nm, respectively, while respective TEM particle size estimate was 79.0 nm and 98.2 nm. BET surface area and total pore volume by BJH for Ag-ZnSnO₃ were estimated with respective values of 17.2 m²/g and 0.05 cm³/g in comparison to 18.8 m²/g and 0.06 cm³/g for ZnSnO₃. Derived energy band gap (Eg) values were 3.8 eV for Ag-ZnSnO₃ and 4.2 eV for ZnSnO₃. Photocatalytic performance of Ag-ZnSnO₃ was tested towards caffeine achieving about 68% removal under (natural) unmodified pH = 6.50 and almost 100% removal at initial pH around 7.5 after 4 h irradiation. The effect of initial pH, catalyst dosage, pollutant concentration, charge scavengers, H₂O₂, contaminant inorganic ions (anions) as well as humic acid (HA) on the photocatalyst activity over caffeine degradation were assessed. In accordance with the probation test of the reactive species responsible for photocatalytic degradation process, a reaction mechanism was deduced.

ZnWO₄MnPc was synthesized via a hydrothermal autoclave method with 1 wt.% manganese (iii) phthalocyanine content. The material was characterized for its structural and morphological features via X-ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, transmission emission microscopy (TEM), scanning electron microscopy-Energy dispersive X-ray spectroscopy (SEM-EDX), N₂ adsorption–desorption at 77K, X-ray photoelectron spectroscopy (XPS), and UV-visible/diffuse reflectance spectroscopy(UV-vis/DRS). ZnWO₄MnPc photocatalytic performance was tested on the degradation of bisphenol A (BPA). The ZnWO₄MnPc material removed 60% of BPA after 4 h of 365 nm UV irradiation. Degradation process improved significantly to about 80% removal in the presence of added 5 mM H₂O₂ after 4 h irradiation. Almost 100% removal was achieved after 30 min under 450 nm visible light irradiation in the presence of same concentration of H₂O₂. The effect of ions and humic acid (HA) towards BPA removal was also investigated.

Photocatalytic coatings of TiO₂/ZnO/CuPc were developed on stainless steel substrates by subsequent sol gel dip coating for TiO₂, spray pyrolysis for ZnO, and spin coating for copper (ii) phthalocyanine (CuPc) deposition. The latter compound was successfully prepared using a Schiff-based process. The materials and coatings developed were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy with attached energy dispersive spectroscopy (SEM-EDS), UV-Vis spectroscopy, room temperature photoluminescence (RTPL) spectroscopy, H1-nuclear magnetic resonance (¹H-NMR) spectroscopy, C13-nuclear magnetic resonance (¹³C-NMR) spectroscopy, and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS). The as-deposited TiO₂/ZnO/CuPc on stainless steel retained in pristine state the structural and morphological/spectroscopic characteristics of its respective components. Estimated energy band gap values were 3.22 eV, 3.19 eV, 3.19 eV for TiO₂, ZnO, TiO₂/ZnO respectively and 1.60 eV, 2.44 eV, and 2.92 eV for CuPc. The photocatalytic efficiency of the fabricated TiO₂/ZnO/CuPc coatings was tested toward ibuprofen (IBF). After 4 h irradiation under 365 nm UV, an increased degradation of about 80% was achieved over an initial 5 mg/L ibuprofen (IBF). This was much higher compared to about 42% and 18% IBF degradation by TiO₂/ZnO and TiO₂ thin film, respectively. In all cases, the stability of the best-performing photocatalyst was investigated showing a small decline to 77% of IBF degradation after the 5th cycle run. The effect of pH, reactive oxygen species (ROS) probe, shed light on a possible catalytic mechanism that was suggested.

This study investigated the synthesis of two different types of photocatalysts, namely, boron/sodium fluoride co-doped titanium dioxide (B/NaF-TiO₂), and its analogue, a dye-sensitized form of silicon-based axial methoxy substituted phthalocyanine (B/NaF-TiO₂SiPc). Structural and morphological characterizations were performed via X-ray diffraction (XRD); Fourier transform infra-red (FTIR); N₂ adsorption–desorption at 77 K by Brunauer–Emmett–Teller (BET) and Barrett, Joyner, and Halenda (BJH) methods; transmission electron microscopy (TEM); X-ray photoelectron spectroscopy (XPS); and UV–visible absorption spectroscopy. The estimated crystallite size of pure TiO₂ and pure B/NaF-TiO₂ was 24 nm, and that of B/NaF-TiO₂SiPc was 29 nm, whereas particle sizes determined by TEM were 25, 28, and 31 nm for pure TiO₂, B/NaF-TiO₂ and B/NaF-TiO₂SiPc respectively. No significant differences between B/NaF-TiO₂ and B/NaF-TiO₂SiPc were observed for surface area by (BET) analysis (13 m²/g) or total pore volume by the BJH application model (0.05 cm³/g). Energy band gap values obtained for B/NaF-TiO₂ and B/NaF-TiO₂SiPc were 3.10 and 2.90 eV respectively, lower than pure TiO₂ (3.17 eV). The photocatalytic activity of the synthesized materials was tested using carbamazepine (CBZ) as the model substrate. Carbamazepine removal after 4 h of irradiation was almost 100% for B/NaF-TiO₂ and 70% for B/NaF-TiO₂SiPc; however, the substrate mineralization proceeded slower, suggesting the presence of organic intermediates after the complete disappearance of the pollutant.