Engineering of ZnO/rGO nanocomposite photocatalyst towards rapid degradation of toxic dyes

Mandal, Sujoy Kumar; Dutta, Shibsankar; Pal, Srimanta; Mandal, Sumit; Naskar, Avigyan; Pal, Pabitra Kumar; Bhattacharya, Tara Shankar; Singha, Achintya; Saikh, Rezaul; De, Sourya Joyee; Jana, Debnarayan

doi:10.1016/j.matchemphys.2018.11.002

Cited by 143 publications

(36 citation statements)

References 56 publications

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“…After implantation, an asymmetric tailing (higher wave number side) of E 2 low mode is found. This is consistent with earlier observations in ion irradiated, ball milled, disordered ZnO, and ZnO composites . This asymmetric tailing can be a cumulative effect of Raman modes at 120, 144, and 183 cm −1 (Figure a,b).…”

Section: Resultssupporting

confidence: 93%

Raman investigation of N‐implanted ZnO: Defects, disorder and recovery

Mondal

Pal

Sarkar³

et al. 2019

J Raman Spectroscopy

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Understanding defects, disorder and doping due to N implantation in ZnO is one of the most debated issues for the last few years. In the present work, a comprehensive investigation has been carried out using Raman, photoluminescence (PL) spectroscopy and grazing‐incidence X‐ray diffraction on 50 keV N ions implanted granular ZnO with different fluence (approximately up to 6.5% atomic concentration) along with postimplantation annealing. Raman investigation suggests that 275, 510, 643, and 857 cm−1 modes are directly related to nitrogen. Additionally, VZn may have some role in stabilizing 275 cm−1 mode. The broadening (or tailing) of E2low mode is related to vibration of distorted Zn sublattice, which may be a product of ion implantation generated defect cluster like VZn–VO. The distortion starts to reduce with annealing at elevated temperatures. Direct correlation between 555 cm−1 Raman mode and the tailing of E2low mode has been found. More defect clustering is vivid from the reduced PL of the ZnO samples with increasing implantation fluence. So, tailing of E2low Raman mode, increasing intensity of 555 cm−1 mode and nonradiative defect centers are of common origin. Both the ratios E1(2LO)/E1(LO) and E2high/E1(LO) can be used as parameters to measure the defective nature of ZnO after ion implantation/irradiation. Low temperature PL (selected samples) suggests absence of shallow acceptor states, although negative thermal quenching above 175 K has been observed (implantation fluence 1 × 1016 ions/cm2 and annealed at 500°C) which can be a signature of deep acceptors.

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Section: Resultssupporting

confidence: 93%

Raman investigation of N‐implanted ZnO: Defects, disorder and recovery

Mondal

Pal

Sarkar³

et al. 2019

J Raman Spectroscopy

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“…Regarding the Raman, UV visible, and XPS analysis, the lower charge carrier recombination may be due to the existence of more defect/oxygen vacancy. Additionally, the GO additive provided the additional carrier pathway, which can increase charge separation efficiency and prolong photocatalytic reaction lifetime [28,63,64].…”

Section: Resultsmentioning

confidence: 99%

Effect of GO Additive in ZnO/rGO Nanocomposites with Enhanced Photosensitivity and Photocatalytic Activity

et al. 2019

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Zinc oxide/reduced graphene oxide nanocomposites (ZnO/rGO) are synthesized via a simple one-pot solvothermal technique. The nanoparticle–nanorod turnability was achieved with the increase in GO additive, which was necessary to control the defect formation. The optimal defect in ZnO/rGO not only increased ZnO/rGO surface and carrier concentration, but also provided the alternative carrier pathway assisted with rGO sheet for electron–hole separation and prolonging carrier recombination. These properties are ideal for photodetection and photocatalytic applications. For photosensing properties, ZnO/rGO shows the improvement of photosensitivity compared with pristine ZnO from 1.51 (ZnO) to 3.94 (ZnO/rGO (20%)). Additionally, applying bending strain on ZnO/rGO enhances its photosensitivity even further, as high as 124% at r = 12.5 mm, due to improved surface area and induced negative piezoelectric charge from piezoelectric effect. Moreover, the photocatalytic activity with methylene blue (MB) was studied. It was observed that the rate of MB degradation was higher in presence of ZnO/rGO than pristine ZnO. Therefore, ZnO/rGO became a promising materials for different applications.

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“…In addition to limiting the recombination of the electron–hole pair, a large number of charges are available on the hybrid surface which helps to produce huge number of above‐mentioned radicals. As compared to ZnO NRs themselves, the increases in surface area and porosity of the ZnO–rGO hybrid NRs provide further means to enhance the photocatalytic activity of the catalyst . Figure b compares the photocatalytic degradation of RhB using the ZnO–rGO hybrid NRs to the equivalent process with a commercial Degussa P25, TiO 2 ‐based catalyst, under UV‐light irradiation the hybrid outperforms P25.…”

Section: Resultsmentioning

confidence: 99%

Microwave‐Assisted Synthesis of ZnO–rGO Core–Shell Nanorod Hybrids with Photo‐ and Electro‐Catalytic Activity

Jana

Gregory

2020

Chemistry A European J

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The unique two-dimensional structure and surface chemistry of reduced graphene oxide (rGO) along with its high electrical conductivity can be exploitedt om odify the electrochemical properties of ZnO nanoparticles (NPs). ZnO-rGO nanohybrids can be engineered in as imple new twostep synthesis, which is both fast and energy-efficient. The resulting hybrid materials show excellent electrocatalytic and photocatalytic activity.T he structure and compositiono f the as-prepared bare ZnO nanorods (NRs) andt he ZnO-rGO hybrids have been extensively characterised and the optical properties subsequently studied by UV/Vis spectroscopy and photoluminescence (PL) spectroscopy (including decay life-time measurements). The photocatalytic degradation of Rhodamine B( RhB) dye is enhanced using the ZnO-rGO hybrids as compared to bare ZnO NRs. Furthermore, potentiometry comparing ZnO and ZnO-rGO electrodes reveals af eatureless capacitive backgroundf or an Ar-saturated solution whereas for an O 2 -saturated solution aw ell-definedr edox peak was observed using both electrodes. The change in reductionp otential and significant increasei nc urrent density demonstrates that the hybrid core-shell NRs possess remarkable electrocatalytic activityf or the oxygen reduction reaction (ORR) as compared to NRs of ZnO alone. Figure 6. (a) Photoluminescences pectra of ZnO NRs and ZnO-rGO NRs, (b) proposedb and diagram of ZnO-rGO hybrid NRs.

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Engineering of ZnO/rGO nanocomposite photocatalyst towards rapid degradation of toxic dyes

Cited by 143 publications

References 56 publications

Raman investigation of N‐implanted ZnO: Defects, disorder and recovery

Raman investigation of N‐implanted ZnO: Defects, disorder and recovery

Effect of GO Additive in ZnO/rGO Nanocomposites with Enhanced Photosensitivity and Photocatalytic Activity

Microwave‐Assisted Synthesis of ZnO–rGO Core–Shell Nanorod Hybrids with Photo‐ and Electro‐Catalytic Activity

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