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Hybrid photocatalytic systems have drawn significant attention to produce renewable hydrogen from water splitting. High performances of hybrid catalysts depend upon synergism and effective charge transfer, specifically during the photoreaction. In this work, Cu–Fe-loaded dual-doped hybrid Si–gC3N4/Al–rTiO2catalysts have been synthesized and introduced. Cu–Fe cocatalysts were deposited by coprecipitation and chemical reduction, whereas Si and Al doping was in situ achieved on hydrothermal reactions. Catalysts were abbreviated as Cu–Fe@Si–CN/Al–TO, where CN = gC3N4and TO = rTiO2. Morphology and optical characteristics have been evaluated by X-ray diffraction (XRD), Raman, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), UV–vis/drs, photoluminescence (PL), electron dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS), whereas the electrochemical response has been justified via electron impedance spectroscopy (EIS) technique. All photoreactions have been performed in a quartz reactor (150 mL/Velp-UK), whereas hydrogen evolution activities have been monitored on a gas chromatograph (GC–TCD/Shimadzu-Japan). Results depict that existence of Al dopants reduced the band gap of rTiO2and has extended its photon/light absorption capability. The Si dopants in gC3N4sheets enhance the overall electron transfer by contributing relatively higher charge induction to active sites. It has been predicted that Cu generates high-energy electrons (i.e., surface plasmon resonance, SPR-induced charges) that progressively transfer to Si–gC3N4, where they are dragged to Al–rTiO2via Fe cocatalysts that act as an electron mediator. Although there are many challenges ahead, the aforementioned catalyst has potential to replace the costly and conventional catalysts that have been priorly used for hydrogen generation technologies.

The ecological impact and rising expenses of fossil fuels have led researchers to investigate alternative renewable-energy sources. Current work reported a novel and sustainable water splitting system comprising TiO2/Pd/Au integrated on g-C3N4surfaces. The phase purity and crystallization were analyzed by XRD, revealing characteristic patterns of TiO2, g-C3N4, and loaded Pd–Au cocatalysts. The electronic and structural properties were analyzed by Raman spectroscopy. The efficient charge separation in Pd/Au@g-C3N4/TiO2was demonstrated by PL spectral and TRPL analyses. Interface analysis, charge transfer resistance/capacitance, and dynamics were evaluated by EIS and temporal photocurrent responses. FTIR spectra indicate the interfacial connection between g-C3N4/TiO2, while UV–vis/DRS revealed that Pd/Au@g-C3N4/TiO2exhibited superior optical absorption (absorption edge at 457 nm). The BET technique confirmed the mesoporous nature of Pd/Au@g-C3N4/TiO2, while SEM demonstrated its lumpy surface morphology with high dispersion of cocatalysts. The elemental compositions and electronic states were further confirmed by EDX and XPS. Hydrogen evolution activities were conducted in the sunlight using a GC equipped with TCD. Activities indicated an encouraging rate of H2generation on fabricated g-C3N4/TiO2heterojunctions (Z-scheme interaction) having a Au-LSPR effect along with a Pd Schottky barrier impact. The maximum H2evolution rate of 36.51 mmol g–1h–1(Q.E = 10.46%) was applied with 5 mg of Pd/Au@g-C3N4/TiO2in the presence of triethanolamine pH 7.5. The durability of Pd/Au@g-C3N4/TiO2catalysts was assessed by recycling tests and optimized by experimental conditions. In the current work, the hydrogen evolved by Pd/Au@g-C3N4/TiO2was ≈11.23- and 6.97-fold higher than those by bulk TiO2(3.25 mmol g–1h–1) and g-C3N4(7.87 mmol g–1h–1), respectively. Based on the results, Pd/Au@g-C3N4/TiO2is recommended for reliable energy and fuel applications.

Drinking ground water in many areas of Pakistan is contaminated by dissolved arsenic. The consumption of arsenic-contaminated water causes many carcinogenic diseases. Hence, this work aims to estimate and eliminate arsenic from ground water used for drinking purposes in the Layyah District (Punjab – PK). For the purpose, water samples were collected from selected areas of the aforementioned district, and average arsenic concentration was estimated to be 95 ppb. Thereafter, to remove dissolved arsenic contents (As3+and As5+), sulphur-doped copper ferrite, i.e., S–CuFe2O4adsorbent, was developed viaa hydrothermal approach. To justify its effectiveness, structural morphology of the adsorbent was evaluated viaXRD, FT-IR, Raman and AFM analysis, whereas its stability was investigated viaTGA analysis. Its purity and chemical compositions were determined using SEM, EDX and XPS techniques. Magnetic properties of S–CuFe2O4were examined viaVSM. The results indicated that spinel cubic morphology of S–CuFe2O4facilitates the effective adsorption of arsenic contents. For complete elimination, arsenic contents were first converted to an arsenomolybdate complex (AMC) and then removed from water viaadsorption on S–CuFe2O4. The adsorption was found to be spontaneous with ΔG= −13.51 kJ mol−1, and adsorption kinetics for the AMC were well fitted by pseudo second order with a correlation coefficient (R2) of 0.99997. Adsorption isotherm and electrostatic interaction between S–CuFe2O4and AMC were confirmed and revealed using Langmuir and Temkin models with R2= 0.97021 and R2= 0.87431, respectively. Results suggested that one gram of S–CuFe2O4is enough to deliver 275 gal of arsenic free water.

In this study, we report a promising approach and new catalysts, namely Au@Al–CeVO4photocatalysts, for sustainable hydrogen production from water splitting. Al doping into CeVO4was done hydrothermally to enhance the electron quenching centres. The structural and optical properties of as-synthesized catalysts were evaluated with XRD, SEM, BET, AFM, EIS and UV-vis–DRS techniques. The purity and chemical compositions were confirmed with EDX and XPS techniques. Electron impedance spectroscopy and photoluminescence were used to ensure the charge transfer mechanism for water splitting on Au@Al–CeVO4. Photocatalytic reactions were done in a quartz reactor, whereas hydrogen generation activities were monitored on a GC-TCD (Shimadzu-2010/Japan). The presence of Au cocatalysts on Al–CeVO4surfaces offers more highly localized electrons to accelerate water reduction. The results of this study show that Au1.0@Al–CeVO4was the most active catalyst, delivering 52.93 mmol g−1h−1of hydrogen compared to bare CeVO4or Al–CeVO4catalysts that deliver 2.57 and 8.69 mmol g−1h−1, respectively. It has been found that gold loading and Al doping reduce the back reaction by localized surface plasmon electrons and electron quenching, respectively. In addition, gold cocatalysts and Al doping enhanced the catalytic sites and light harvesting ability of Au@Al–CeVO4. On the basis of these results, it can be concluded that the aforementioned approach shows eventual promise to replace conventional technologies used for hydrogen generation.

Arsenic is regarded as a highly toxic element that naturally exists in ground drinking water. Owing to its inherent carcinogenic nature, arsenic free water becomes necessary for a healthy life. To remove arsenic from the ground drinking water, the Bahawalnagar district of Pakistan was chosen for sample collection. For the complete removal of dissolved arsenic contents (AsIII/AsV), ferrites have been found to be very effective in purifying natural water. In this study, sulphur-doped copper ferrites (CuFe2SxO4−x) were synthesized for the first time using a hydrothermal strategy. XRD results revealed that CuFe2SxO4−xhas spinel cubic structures, whereas SEM results illustrate that spherical morphologies indicate higher adsorption of arsenic over CuFe2SxO4−x. The purity and elemental compositions were confirmed by EDX results, whereas the stability was revealed by thermogravimetric analysis (TGA). For the quantitative study, dissolved arsenic contents were converted into an arsenomolybdate complex (AMC). The adsorption of AMC on CuFe2SxO4−xwas found to be a spontaneous process (ΔG= −13.41 kJ mol−1). The adsorption kinetic performances of CuFe2SxO4−xfor AMC were well fitted by pseudo first order and had the correlation coefficient R2= 0.95458. The adsorption isotherm data for AMC removal were fitted with the Langmuir model (R2= 0.99981), whereas an electrostatic relationship between CuFe2SxO4−xand AMC (R2= 0.66186) was revealed by the Temkin model. The maximum adsorption capacity observed on CuFe2SxO4−xwas 188.8 mg g−1, which is higher than those from previous reports.

The coexistence of organic contaminants and Cr metal in industrial sewage pollutes drinking water reservoirs. These toxins produce consistent health issues not only for the aquatic but also for terrestrial life. This project aims to eliminate selective organic dyes, and ciprofloxacin (CIP) and Cr(vi) contents from the water of various industrial zones of Pakistan. To remove these contaminants effectively, BiVO4and silver deposited (Ag–BiVO4) catalysts were synthesized by hydrothermal treatment. The morphologies of the as-prepared catalysts were evaluated and confirmed viaXRD, FT-IR, Raman, SEM and AFM analysis, whereas the optical characteristics and chemical composition were obtained by UV-vis-DRS, PL, EDX and XPS techniques. BET analysis was conducted for the pore volume and surface area measurements. UV-vis spectrophotometry (PerkinElmer λ-365) was used to monitor the photocatalytic dye degradation reactions. Results of this project depict that the as prepared Ag–BiVO4catalysts have the ability to remove 92.6% of methylene blue (MB), 66.8% of rhodamine B (RhB), 99.2% of crystal violet (CV), and 98.6% of Congo red (CR). Similarly, 98.2% of ciprofloxacin (CIP) and 95.63% of Cr(vi) were eliminated simultaneously from contaminated water. The higher catalytic efficiencies were attributed to the surface plasmon electrons of silver and formation of a Schottky junction on BiVO4surfaces. In addition, the effect of pH on catalytic activities was optimised. On the basis of results, it could be concluded that this work has the potential to remove toxic contents from polluted water that can diminish the health issues in aquatic and terrestrial life.