One-Pot Facile Synthesis of CuO–CdWO4 Nanocomposite for Photocatalytic Hydrogen Production (original) (raw)
Related papers
Journal of Environmental Chemical Engineering, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
CuO Quantum Dots Decorated TiO2 Nanocomposite Photocatalyst for Stable Hydrogen Generation
Industrial & Engineering Chemistry Research, 2018
An efficient and stable CuO-TiO 2 nanocomposite photocatalyst was synthesized by using simple molten-salt method. Characterization by HR-TEM confirmed existence of both TiO and CuO in the nanocomposite, revealed hexagonal TiO nanoparticles (NPs) with average particles size of 23.8 nm. CuO QDs decorated on TiO 2 surface was in the range of 2.2 to 4.6 nm. Photocatalytic experiments for hydrogen (H 2) production were carried out under LED (λ=365 nm) lamp and natural solar light. The effect of Cu-loading in CuO-TiO 2 NCs and synthesis time were studied. The optimized CuO-TiO 2 NCs abbreviated as CuT-4 and CuT-3 showed 27.7 and 9.0 folds superior rate of H 2 production compared to pristine TiO 2 NPs under LED and solar irradiation respectively. At optimal conditions CuO-TiO 2 NCs demonstrated good photoactivity for H 2 evolution during 75 h illumination under LED light. The experimental results confirmed the cocatalytic role of CuO for improved H 2 generation by minimized recombination of excitons.
Ceramics International, 2019
Cadmium tungstate (CdWO 4) photocatalyst was successfully fabricated with flower like nanosheets-assembly (FNA) by modified hydrothermal method. The as-synthesized nanostructures were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), BET surface area analysis, Fourier Transform Infrared spectroscopy (FTIR) and Photoluminescence (PL). The photocatalytic degradation performance of FNA was explored for two model dyes, Congo red (CR) and methyl orange (MO), under visible light irradiation while hydrogen absorption features were also studied at three different temperatures. Slight difference in degradation rate constants is observed for CR and MO dyes i.e. 0.0262 min-1 and 0.0517 min-1
The Potential of Supported Cu 2 O and CuO Nanosystems in Photocatalytic H 2 Production
ChemSusChem, 2009
Over the last decade, owing to their possible applications in various areas, p-type semiconducting Cu 2 O-and CuO-based nanostructures have been the focus of a great interest. Cubic Cu 2 O (E g % 2.1 eV) and the monoclinic CuO (E g % 1.2 eV) both have a broad perspective of attractive utilizations as active components in superconductors, electrode materials, field emitters, solar cells, and photocatalysts. In the latter context, a challenging and strategic concern is actually the use of copper oxide based nanosystems for the direct photocatalytic splitting of water, an attractive solution to provide clean and recyclable H 2 energy in view of increased environmental concerns. To date, most of the investigations have focused on the use of nanocomposite Cu x O-TiO 2 (x = 1, 2) systems, whereas the properties of pure copper oxides in these fields, especially as a function of their nanoscale organization, have been scarcely addressed despite their extensive use in solar cell devices. In particular, pure Cu 2 O and CuO thin films have been reported to be inactive in H 2 O photocatalytic splitting, as a result of very fast recombination phenomena and the position of the conduction band edge, respectively. Nevertheless, the design of supported nanostructured photocatalytic films can enhance performances and eliminate the necessity of filtration processes for recovery of the powdered catalyst. In fact, the development of effective and low-cost preparation routes for these materials is still an ongoing challenge. Herein, we demonstrate for the first time that tailoring the system morphology by appropriate synthetic strategies is a key tool to achieve unprecedented performances of the CuÀO system in photo-activated H 2 generation even in the absence of TiO 2 . In particular, we report on a chemical vapor deposition (CVD) approach to obtain copper oxide nanostructures. The systems were grown under O 2 -based atmospheres on HFetched
Solar Energy Materials and Solar Cells, 2016
A series of Cu doped titania, Cu x Ti 1 À x O 2 À δ (x¼0.0, 0.02, 0.06) and copper oxide-titanium oxide nanocomposites, xCuO-yTiO 2 (x:y¼ 1:9, 2:8, 5:5) were synthesized by sol-gel method and characterized by relevant techniques. The role of Cu ions in enhancement of photocatalytic evolution of H 2 from H 2 Omethanol/glycerol mixtures in both sunlight and UV-visible irradiation over Cu/Ti oxides was investigated. X-ray absorption fine structure (XAFS), supported by X-ray diffraction and Raman studies, revealed that Cu substitution in TiO 2 stabilized anatase lattice, lengthened Ti-O bonds, decreased the coordination number around Cu ions, and induced oxygen ion vacancies and distortion (σ) in lattice. Distorted structures are more open and flexible with improved charge carrier dynamics and favourable photocatalytic properties. Nanosized Cu-Ti-O powders with enhanced N 2-BET surface area and microporosity exhibited improved photocatalytic properties. Reduction of CuO to photocatalytically more active Cu 2 O by photo-generated eon the surface of composites was evident by the absence of Cu 2 þ peak in the XPS spectra of the composite sample after exposure to light. The most active formulations for sunlight assisted photocatalytic H 2 generation were Cu 0.02 Ti 0.98 O 2 for the doped samples, referred to as CuTi(2), and xCuO-yTiO 2 (x:y ¼2:8) for the composite samples. Performance of the most active, CuTi(2), was monitored in a up-scaled photoreactor in order to investigate the influence of illumination area, catalyst concentration, form of catalyst (powder/films) and different sacrificial agents on H 2 yield. With an aim to identify practical materials for pilot plants, 6 mg of CuTi(2) was dispersed on (30 cm  0.7 cm) ITO/PET films that exhibited enhanced efficiency (3.06%) as compared to same amount of CuTi(2) powder (1.41%). The results showed that the utilization of the CuTi(2) photocatalyst (without costly cocatalysts) with the proper selection of optimum operational conditions under sunlight in a up-scaled photoreactor, generated H 2 yield of 1.167 L/h/m 2 with apparent quantum efficiency, AQE, of 7.5% and solar to fuel efficiency, SFE, of 3.9% for the photocatalytic hydrogen evolution reaction (HER). Our results suggest that with this efficiency, H 2 at 1 L/h would be evolved photocatalytically over 0.9 m 2 of CuTi(2) photocatalyst, exposed to sunlight. Inputs obtained from the present study will be useful for further scale up of sunlight driven photocatalytic hydrogen production over low cost and efficient Cu modified TiO 2 .
The advanced photocatalytic performance of V doped CuWO4 for water splitting to produce hydrogen
International Journal of Hydrogen Energy, 2019
energy band gap but also increased the CB potential of the material. Therefore, the V eCuWO 4 generated significant amount of e À under visible light and the generated e À was strong enough to react with H þ to produce H 2. The optimal V/W ratio for maximum improving photocatalytic performance of the CuWO 4 was 6 wt%. Finally, we investigated that our prepared VeCuWO 4 showed high stability during long-term water splitting process.
Journal of Materials Science: Materials in Electronics, 2016
The present investigation reports a simple hydrothermal process for synthesizing Cu and CuO nanostructures using new set of low-cost starting reagents including CuSO 4 Á5H 2 O, ethylenediamine and hydrazine hydrate. The obtained nanostructures were characterized by techniques such as XRD, SEM, EDX, DRS and FTIR. Effect of hydrazine hydrate, ethylenediamine, reaction temperature and time on morphology of prepared nanostructures was well studied. Our results showed ethylenediamine and hydrazine hydrate play crucial role on particle growth, formation mechanism of nanostructures and consequently on morphology of nanostructures. Furthermore, the efficiency of CuO nanostructures as a photocatalyst for the decolorization of methylene blue using ultraviolet light irradiation was evaluated and the CuO nanoparticles compared to nanorods showed more efficient photocatalytic activity.
ChemCatChem, 2019
Copper doped-TiO2 (P25) nanomaterials have been intensively studied as promising catalysts for H2 production by photo-reforming of selected organic compounds. However, the role of copper oxidation states on the improvement of photocatalytic activity is still debated. In this work, CuOx-impregnated P25-TiO2 catalysts were used for photocatalytic production of hydrogen from methanol. Copper species/oxidation states both in the as-prepared catalysts and after the photocatalytic process were investigated. To this purpose, H2 production rates were correlated to physico-chemical properties of the samples, both before and after photocatalytic process, by means of Raman, X-Ray Diffraction, Electron Paramagnetic Resonance spectroscopy, X-Ray Photoelectron Spectroscopy, Temperature-Programmed Reduction and High Resolution Transmission Electron Microscope techniques. Results revealed the presence of both Cu2O and CuO deposits on the samples surface after calcination. Notably, under near-UV irradiation, the fraction of highly dispersed CuO particles undergo a partial dissolution process, followed by reduction to metallic copper Cu(s) by photogenerated electrons, boosting H2 production rate. Our findings indicate that both Cu2O and Cu(s) act as co-catalysts for H2 generation, yet by different mechanisms. Overall this study, lies the basis to enhance catalytic performance of red-ox active systems through UV-irradiation approach.
Journal of Alloys and Compounds, 2020
The heterogeneous structure of Cu 2 O quantum dots (QDs) sensitized CdS nanorods (NRs) was synthesized by an easy and cost-effective technique. The morphology, structure and optical properties of asprepared photocatalysts are thoroughly investigated by field emission gun scanning electron microscopy (FEG-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (UVDRS) and photoluminescence (PL) spectroscopic techniques. The different weight percentages (10, 20, and 30) of Cu 2 O QDs deposited on the CdS NRs structures and their photocatalytic hydrogen (H 2) evolution (PCHE) performance are systematically investigated. The Cu 2 O QDs deposition on CdS NRs shows an increase in the rate of hydrogen (H 2) evolution due to the formation of type II heterojunction in between Cu 2 O QDs and CdS NRs. The 20% loading of Cu 2 O QDs on CdS exhibits the highest photocatalytic H 2 generation than other ratios as well as pure Cu 2 O QDs and CdS NRs. The photocatalytic rate of H 2 evolution of 26060 mmolg-1 h-1 was obtained for 20 % Cu 2 O-CdS, which is18 times more than pure Cu 2 O QDs and 5.1 times than CdS NRs. Photoelectrochemical (PEC) measurements, electrochemical impedance spectroscopy, and photoluminescence measurements suggest that the Cu 2 O QDs deposition on CdS NRs reduces interfacial recombination of photogenerated charge carrier owing to the formation of the p-n junction between the components. The apparent quantum yield (AQY) obtained for 20 % Cu 2 O QDs modified CdS NRs photocatalysts is exceptionally high i.e. 20.67%. This convenient and cost-effective strategy will pave the way for large-scale synthesis of type II heterogeneous photocatalyst for efficient H 2 evolution.