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In this study, pure ZnO and iron (Fe) and cobalt (Co) co-doped ZnO nanoparticles were synthesized by varying Fe and Co concentrations using the co-precipitation method. The physical properties of as-prepared samples were investigated through XRD, FTIR, SEM, and UV–vis spectroscopy. X-ray diffraction confirmed the strong influence of Fe and Co ions on structural parameters without disturbing the basic ZnO hexagonal structure. The microstructural study was executed by using the Scherrer, W–H, and SSP methods. FTIR confirmed the presence of Zn–O, and Zn–M–O (M = Fe, Co) vibrational modes, which further confirmed the successful incorporation of dopants ions. The energy bandgap (E g) extracted from UV–vis spectra has shown red-shift (3.37–2.7 eV) for decreasing Fe contents, whereas blue-shift (3.37–3.39 eV) for increasing Co concentration. SEM was used to investigate surface morphology, which represents the high rate of agglomeration. The photocatalytic test was performed on grown samples against various dyes and also observed the effects of varying concentrations of Fe and Co ions. The maximum degradation efficiency (98.8%) at 6%Fe and 4%Co under direct sunlight in 60 min against methylene blue (MB) was achieved. The photocatalytic activity of optimized concentration (6%Fe and 4%Co) was further tested against cresol red (CR), methyl orange (MO), safranin-O (SO), rhodamine-B (RhB), and methyl red (MR) dyes. The maximum degradation efficiency against MR dye (96.0%) was observed. The antibacterial test against Staphylococcus aureus and Klebsiella pneumoniae bacterial strains have shown that co-doped ZnO nanoparticles have a higher activity as compared to pristine ZnO, and furthermore, the sample with 6%Fe and 4%Co concentration exposed the highest antibacterial actively for both bacterial strains. [ABSTRACT FROM AUTHOR]

[Display omitted] • NiVCuO/C 60 nanocomposites synthesized for the first time by solution method. • Recent advances in properties modified with fullerene were discussed. • Excellent photocatalytic application modified with fullerene. • Tuning the band gap and surface of the NiO catalyst. • Degradation of dyes (MB, RhB, SO, and CR) dye more efficiently. NiO act as an efficient photocatalyst, and an appropriate design is necessary to support simultaneous highest photon absorption and lower charge carrier recombination. In this study, V/Cu were co-doped in NiO nanoparticles and then coupled with fullerene (C 60). X-ray diffraction and FTIR spectroscopy are used to investigate the structural variations. Further characterization tools were used to disclose the origin of surface imperfections inside the nanostructures, including Raman, UV, and PL spectroscopy. XPS was employed to examine the chemical composition of Ni, Cu, V, and C. EDX confirmed the elements in NiVCuO/C 60 composition. These imperfections decrease the charge carrier recombination and improve photocatalytic degradation (∼99.8%) of RhB dye, with a rate constant ∼0.042 min−1 under sunlight exposure. In addition, NiCuVO/C 60 has degradation efficiency of 99.5, 98.6, and 75% towards SO, MB, and CR dyes, respectively. The fabricated NiVCuO/C 60 nanocomposite achieved the high degradation required for practical application. [ABSTRACT FROM AUTHOR]

Au nanoparticles of size ranging 2–6 nm were deposited over hexagonal CdS using three conventional metal deposition methods namely; deposition precipitation (DP), incipient wet impregnation (WI), photo-deposition (PD) and a recently reported KI method by our group [1]. The later involves reduction of Au 3+ ions with iodide ions. XRD results confirmed the formation of CdS hexagonal phase from as prepared cubic phase at 600 °C under the N 2 atmosphere. Transmission electron spectroscopy (TEM), diffused reflectance spectroscopy (DRS), X-Ray fluorescence (XRF), ICP-OES and photoreactions were conducted to study the effect of Au particle size, Au loading and Au plasmonic properties on H 2 production activity. It was found that surface plasmon resonance (SPR) is directly linked to Au particle size. Among all four methods, 3 wt.% Au deposited over hexagonal CdS by KI method with mean Au particle size of 4 nm showed highest performance for hydrogen production from water electrolyte mixture under visible light irradiation (>420 nm and a flux of 35 mW/cm 2 ). XPS results of Au/CdS prepared by KI method showed that Au is exclusively present in zero oxidation state before and after photocatalytic H 2 production testes indicating the stable nature of Au/CdS catalyst. The H 2 production activity of Au/CdS catalysts prepared by different metal deposition methods and H 2 production mechanism in a water-electrolyte is discussed in detail. [ABSTRACT FROM AUTHOR]

Novel Zn 0 · 95 Mn 0 · 05 O and Zn 0 · 9 Mn 0.05 M 0.05 O (M = Al, Bi, Sr, Ag) nanocrystals were prepared via the co-precipitation technique. The X-ray diffraction pattern confirmed the substitution of Mn, Al, Bi, Sr, and Ag dopants without altering the basic ZnO structure. The microstructural study was performed by employing the Scherrer plot, Williamson-Hall, and SSP methods. The energy bandgap calculated from UV–vis spectra using different methods observed red-shifted by co-doping. The other optical parameters were also studied and discussed in detail. The FTIR spectra confirmed the presence of Zn–O, and Zn-M–O vibrational modes. Raman spectra demonstrated the presence of ZnO phonon modes, and the Raman shift exhibited the structural defects induced by dopants. The PL spectra showed strong NBE and DLE in the UV and visible region due to extrinsic defects. The IV measurements exhibited the enhancement in the electrical conductivity of ZnO by co-doping. The photocatalytic activity was performed under direct sunlight for methyl orange and methylene blue dyes, and the enhanced degradation efficiency was achieved by co-doping. Furthermore, this article enhances the understanding of tuning the physical properties of ZnO by co-doping and introduces a new class of sunlight-driven photocatalysts. [ABSTRACT FROM AUTHOR]

• Direct dual Z-scheme TiO-WO 3 -CeO 2 heterostructured nanocomposite successfully synthesized by co-precipitation route. • The nanocomposite TiO-WO 3 -CeO 2 showed boosted photocatalytic activity towards different pollutants. • Systematic investigations confirmed the superior charge separation by direct dual Z-scheme. • Enhanced antibacterial activity of nanocomposite against various pathogenic bacterial strain. • The higher super-capacitive behaviour of nanocomposite. [Display omitted] Direct dual Z-scheme heterostructured nanocomposite TiO 2 -WO 3 -CeO 2 (NC) and pristine metal oxides nanostructures (NSs) were fabricated using a facile co-precipitation route. XRD, FTIR, and Raman data have confirmed the formation of NSs and NC. FESEM images showed quasi-mesoporous morphology of as-grown nanocomposite. EDX analysis confirmed the existence of titanium (Ti), cerium (Ce), and tungsten (W) in grown NC. The energy bandgap of NC was narrow 2.45 eV as compared to NSs. The higher electrical conductivity and lower recombination rate of NC were observed in IV and PL analysis. The photodegradation efficiency of NC was recorded 99.8% after 60 min under sunlight radiation against methylene blue (MB), which was significantly higher than NSs. NC catalyst has shown excellent photodegradation against other organic pollutants and has superior recyclability up to 7th cycle toward MB dye with a ~ 6% deficit in photodegradation efficiency. The antimicrobial activity results indicated the higher inhibition ability of NC against E. coli , K. pneumoniae , S. aureus , P. Vulgaris , and P. aeruginosa with maximum inhibition zone diameter 25, 29, 26, 28, and 27 mm, respectively. The electrochemical tests including CV, EIS, and GCD exhibited the superior capacitive behaviour of NC. These results demonstrate that grown NC is an efficient material for electrochemical devices, water purification, and biomedical applications. [ABSTRACT FROM AUTHOR]

In this study, the micro-emulsion approach was adopted to fabricate rare earth (Nd) and transition metal (Cu) co-doped barium hexaferrite (Ba 1-x Nd x Fe 12-y Cu y O 19) nanoparticles (NPs). The fabricated co-doped and undoped materials were characterized by FTIR, XRD, and SEM techniques for structural and morphological investigation. Structural studies such as XRD and FTIR confirmed Nd and Cu doping at the tetrahedral and octahedral sites of barium hexaferrite, respectively. The SEM analysis made sure that the materials were successfully produced at the nanoscale. Dielectric measurements revealed that the dielectric constant and AC conductivity values of the co-doped sample were higher than those of the undoped sample. The VSM study confirms the improved magnetic properties of the sample after co-doping that facilitates its separation and reuse after photocatalytic experiments. The co-doped and undoped sample's photocatalytic activities (PCA) were explored by comparing their Methyl Green (MG) dye degradation efficiencies. The results revealed that the co-doped barium hexaferrite sample degraded almost 92.6% of the MG dye, while the undoped sample degraded just 37.4%. The higher PCA of the co-doped sample is credited to its structural defects, which adjust the band interval to increase electrical conductivity. In addition, the co-doped sample lost only 2% photocatalytic efficiency after five successive cycles, demonstrating its potential for reuse. Application studies have clearly shown that our Nd-Cu co-doped barium hexaferrite sample has a great potential for practical application to remove toxic dyes from the environment. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, tri-phase direct dual S-scheme ZnO–V 2 O 5 –WO 3 heterostructured nanocomposite and pure ZnO, V 2 O 5 , and WO 3 nanoparticles were synthesized by using a facile co-precipitation approach to investigate antibacterial and photocatalytic characteristics of the grown nanocomposite. The physical properties of as-synthesized products were examined by employing characterization techniques such as Scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman, Fourier transform infrared spectroscopy (FTIR), and UV–vis spectroscopy. The XRD results confirmed the formation of pristine ZnO, V 2 O 5 , WO 3 nanoparticles and the existence of diffraction peaks related to hexagonal phase ZnO, orthorhombic V 2 O 5 , and monoclinic phase of WO 3 in ZnO–V 2 O 5 –WO 3 nanocomposite. The variation in structural parameters was studied by SSP, Scherrer plot, and W–H models. The energy bandgap of nanocomposite (2.63 eV) was calculated from UV–vis spectroscopy, which indicated the usability as a photocatalyst under direct sunlight. FTIR and Raman's spectra also supported the formation of the ZnO–V 2 O 5 –WO 3 nanocomposite. Spherical and roughly hexagonal morphology were seen in SEM images. EDX analysis has confirmed the existence of Zn, V, W, and O in the nanocomposite. The antibacterial test against Klebsiella pneumonia, Staphylococcus aureus , Proteus Vulgaris, and Pseudomonas aeruginosa bacteria showed higher activity. The photocatalytic performance of the ZnO–V 2 O 5 –WO 3 nanocomposite (99.8%) was the highest against methylene blue (MB) as compared to pure ZnO (78.8%), V 2 O 5 (85.8%), and WO 3 (80.0%) under natural sunlight. The degradation efficiency of ZnO–V 2 O 5 –WO 3 against cresol red (CR), rhodamine-B (RhB), methyl orange (MO), safranin-O (SO), and methyl red (MR) dyes was 67.0%, 86.6%, 98.0%, 76.8%, and 99.0%, respectively, under direct sunlight in 80 min. Different schematic models are designed to illustrate the photocatalytic reaction mechanism, whereas the separation of charge carriers and enhanced photocatalytic performance can be efficiently explained by S-scheme. [Display omitted] • Facile synthesis of tri-phase direct dual S-scheme ZnO–V 2 O 5 -WO 3 heterostructured NC and pure ZnO, V 2 O 5 , and WO 3 NPs. • SEM, EDX, XRD, Raman, FTIR, and UV–vis was carried out. • The photocatalytic performance was tested against MB, CR, RhB, MO, SO, and MR dyes. • S-scheme is more efficient than other schemes for enhancing photocatalytic activity. • The antibacterial test against different bacteria strain was performed. [ABSTRACT FROM AUTHOR]

Novel excellent antibacterial agent and efficient photocatalyst direct dual Z-scheme ZnO–CeO 2 -Yb 2 O 3 heterostructured nanocomposite and pristine ZnO, CeO 2 , and Yb 2 O 3 were prepared via a simple co-precipitation technique. The X-ray diffraction spectra confirmed the formation of pristine ZnO, CeO 2 , and Yb 2 O 3 , and the existence of their peaks ZnO (hexagonal), CeO 2 (cubic), and Yb 2 O 3 (cubic) in the nanocomposite. The Scherrer, Williamson-Hall, and Size-Strain plot models were used to measure the microstructural parameters. The UV–vis spectroscopy revealed the energy bandgap 3.0 eV, evident that the grown nanocomposite is a good photocatalyst under sunlight. The formation of the ZnO–CeO 2 -Yb 2 O 3 nanocomposite is further confirmed by Raman and Fourier transform infrared spectroscopy (FTIR). Current-Voltage (IV) measurements shown the ohmic nature of nanocomposite with high electrical behavior. Scanning electron microscopy (SEM) images revealed a cluster type morphology. The antibacterial activity was carried out for Escherichia coli and Staphylococcus aureus bacteria. The zone of inhibition (ZOI) showed higher antibacterial activity for E. coli bacteria. The nanocomposite showed the highest photocatalytic degradation efficiency against methylene blue as compared to rhodamine-B, methyl orange, cresol red, and safranin-O dyes under 40 min of sunlight illumination. The impact of various parameters on the photocatalytic activity of nanocomposite, including catalyst amount, dye concentration, and solution pH, was also investigated. The scavenger's experiments were performed to ascertain the reactive species and confirmed the mechanism based on Z-scheme. The recyclability test exhibits that the as-obtained nanocomposite has high stability and can be reusable for the 6th cycles. Image 1 • Novel excellent antibacterial agent and efficient photocatalyst direct dual Z-scheme ZnO–CeO 2 -Yb 2 O 3 heterostructured nanocomposite. • The antibacterial activity was carried out for Escherichia coli and Staphylococcus aureus bacteria. • The mechanism of enhanced antibacterial activity was also proposed. • The photocatalytic test was carried out against MB, MO, CR, RhB, and SF dyes under sunlight illumination. • The recyclability test exhibits that the as-obtained nanocomposite has high stability and can be reusable for 6th cycles. [ABSTRACT FROM AUTHOR]

Novel direct dual Z-scheme ZnO-Er 2 O 3 -Nd 2 O 3 @rGO heterostructured nanocomposite along with simple ZnO-Er 2 O 3 -Nd 2 O 3 nanocomposite was prepared by co-precipitation route. The X-ray diffraction pattern exhibited the diffraction peaks associated with ZnO (hexagonal), Er 2 O 3 (cubic), and Nd 2 O 3 (hexagonal) in both nanocomposites. The FTIR spectra further confirmed the formation of nanocomposites. The energy bandgap of simple and rGO decorated nanocomposites were 3.1 and 2.82 eV. The antibacterial characteristics of grown samples showed that the rGO anchored nanocomposite has higher antibacterial activity as compared to simple nanocomposite. The ZnO-Er 2 O 3 -Nd 2 O 3 @rGO nanocomposite exhibited higher photodegradation (97.0%) against methylene blue (MB) than simple nanocomposite (86.0%). The effectiveness of grown ZnO-Er 2 O 3 -Nd 2 O 3 @rGO nanocomposite as photocatalyst was also tested for degradation of other dyes such as RhB, MO, CR, and SO. The effect of operating parameters was investigated for ZnO-Er 2 O 3 -Nd 2 O 3 @rGO nanocomposite. A possible conventional heterojunction and Z-scheme for the degradation using ZnO-Er 2 O 3 -Nd 2 O 3 @rGO nanocomposite has been designed to elucidate the photocatalytic mechanism. • ZnO-Er 2 O 3 -Nd 2 O 3 and ZnO-Er 2 O 3 -Nd 2 O 3 @rGO nanocomposites successfully prepared. • The photocatalytic application was studied using MB, RhB, MO, CR and SO dyes. • The effect of operating parameters for the degradation of SO dye investigated. • The antibacterial activity against different bacterial strains was investigated. [ABSTRACT FROM AUTHOR]

In this work, novel sunlight driven photocatalyst direct dual Z-scheme ZnO-Sm 2 O 3 –Y 2 O 3 @rGO heterostructured nanocomposite was synthesized through co-precipitation technique. The obtained products were characterized by XRD, FTIR, SEM, I–V, and UV–vis to investigate structural, morphological, electrical, and optical properties. The photocatalytic activity of ZnO-Sm 2 O 3 –Y 2 O 3 @rGO nanocomposite against MB dye is approximately 98.5% at 75 min under sunlight irradiation, which is higher than simple ZnO-Sm 2 O 3 –Y 2 O 3 nanocomposite 78.0%. The enhanced photocatalytic properties are attributed to the presence of Z-scheme and the use of rGO, which acts as electrons/interfacial mediators and reduced electron/hole pair recombination. Furthermore, the photocatalytic experiments were also performed by varying conditions using ZnO-Sm 2 O 3 –Y 2 O 3 @rGO nanocomposite. The trapping experiments and reusability test was also carried out. Image 1 • Sunlight driven photocatalyst direct dual Z-scheme ZnO-Sm 2 O 3 -Y 2 O 3 @rGO heterostructured nanocomposite. • Structural, morphological, electrical, and optical studies of grown nanocomposite. • Detail study of photocatalytic activity. • The different possible schemes were designed to elaborate the photocatalytic mechanism. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Novel 3D [{NiII(4,4′-dipy) 4 }{Ni(CN) 4 }] n (1)) coordination polymer has been synthesized. • Compound 1 is functionalized by making its composite with P25 (titanium dioxide). • The 1 /TiO 2 composite is used as a photocatalyst for H 2 production from water. • The 5 wt% 1 /TiO 2 composite showed the maximum H 2 production of 11.2 mmol h−1 g−1. Abstract A new three dimensional (3D) cyanide-bridged homo-metallic coordination polymer [{NiII(4,4′-dipy) 4 }{Ni(CN) 4 }] n ·(4,4′-dipy)·3H 2 O·C 2 H 6 O 2 (1) (4,4′-dipy = 1,3-di(4-pyridyl)propane) has been functionalized by making its composite with P25 (titanium dioxide) for photocatalytic hydrogen production from water. 1 /TiO 2 composite manifests appreciable hydrogen production in contrast with the virgin compounds 1 and P25, accentuating that the photocatalytic activity greatly corresponds to the well separation of photo generated charge carriers. Different wt% (2.5%, 5%, 7% and 10%) of 1 in 1 /TiO 2 composites were assessed for photocatalytic activity in 5 vol% glycerol water mixture. The 5 wt% 1 /TiO 2 composite showed the maximum hydrogen production of 11.2 mmol h−1 g−1. The veiled mechanism is revealed on the basis of results obtained by cyclic voltammetry, photoluminescence and diffused reflectance UV–visible studies. The key step in proposed mechanism is the transfer of electrons from conduction band of TiO 2 to compound 1. Compound 1 not only quenches the conduction band electrons of titania but also acts as a co-catalyst to reduce the protons into hydrogen. This outcome is envisaged to manage the future advancement of proficient, inexpensive semiconductor photocatalysts for solar Hydrogen production. [ABSTRACT FROM AUTHOR]

Abstract A two dimensional Cu/Ni based coordination polymer [{CuII(4,4ʹ-dipy) 2 }{Ni(CN) 4 }] n ·0.7(C 2 H 6 O 2)·1.6(H 2 O) (CP-1) (4,4ʹ-dipy = 1,3-di (4-pyridyl)propane) has been demonstrated as a potential co-catalyst on TiO 2 support for hydrogen evolution under UV light. CP-1 /TiO 2 composite exhibits considerable hydrogen production in comparison with the pristine CP-1 and TiO 2 (P25), highlighting that the photocatalytic performance is significantly related with the good separation of photo generated e−/h+ pairs. Different wt. % (2.5, 5 and 7.5%) of CP-1 in CP-1 /TiO 2 composites were tested for photocatalytic hydrogen production in 5 vol % glycerol/water mixture. The 5 wt % CP-1 /TiO 2 composite displayed the greatest hydrogen production of 9.2 mmolh−1g−1. The concealed mechanism is divulged on the behalf of results obtained by cyclic voltammetry, photoluminescence and diffused reflectance/UV-visible studies which demonstrate that upon irradiation of UV light, electrons transfer from TiO 2 conduction band to CP-1. CP-1 not only grabs the conduction band electrons of titania but also performes as a co-catalyst to reduce the protons into hydrogen. These results are anticipated to direct the forthcoming advancement in creating proficient, cheap semiconductor photocatalysts for solar hydrogen production. Graphical abstract Image 1 Highlights • A composite of bimetal (Cu/Ni) coordination polymer (CP-1) and TiO 2 is synthesized. • CP-1/TiO 2 composite is utilized as photocatalyst for H 2 generation from water. • The 5 wt % CP-1/TiO 2 composite displayed H 2 production of 9.2 mmolh−1g−1. [ABSTRACT FROM AUTHOR]

Developing effective and noble-metal-free electrocatalysts for the grim oxygen evolution reaction (OER) and photocatalysts for pollutant elimination is critical for long-term energy supply and environmental remediation. Herein a simple sol-gel technique is used to synthesize NiO/C60 electrophotocatalyst and is characterized via different state-of-art techniques. All the characteristic analytical studies have discovered that the structural components dramatically increased the OER and photocatalytic activity for grown NiO/C60 nanocomposite. TEM results showed that the C60 uniformly covering NiO has a particle size of 46 nm. NiO/C60 electrocatalyst has outperformed the overpotential of 310 mV at a current density of 10 mA/cm2. At the applied voltage, electrochemical impedance spectroscopy showed that the catalytically active surfaces of NiO/C60 and charge transfer rate are much greater than simple NiO. It was also discovered that the grown nanocomposite remained stable for 30 h without degrading, outlasting numerous recent noble-metal-free electrocatalysts. In addition, the NiO/C60 has also exhibited excellent photocatalytic reduction efficiency for Methylene blue (MB) dye and completely degraded after 40 min under sunlight with the stability of up to six cycles. Our findings show that NiO-based water oxidation electrocatalysts and efficient photocatalysts may now be produced at a low cost with outstanding performance. Recycleable core-shell NiO/C60 photocatalyst and electrocatalyst. [Display omitted] • Development of NiO/C60 core-shell electrocatalyst/photocatalyst. • Lower overpotential 310 mV and Tafel slope 43 mV/dec at 10 mA/cm2 for OER. • Complete MB dye degradation in 40 min under natural sunlight. • Remarkable stability 1500 cycles for OER and 6 cycles for photocatalysis. • Dual-functional, low-cost, noble-metal-free catalyst with outstanding performance. [ABSTRACT FROM AUTHOR]