Sustainable hydrogen production for the greener environment by quantum dots-based efficient photocatalysts: A review

Rao, Vempuluru Navakoteswara; Reddy, N. Lakshmana; Kumari, M. Mamatha; Cheralathan, K.K.; Ravi, P.; Sathish, M.; Neppolian, B.; Reddy, Kakarla Raghava; Shetti, Nagaraj P.; Prathap, P.; Aminabhavi, Tejraj M.; Shankar, M.V.

doi:10.1016/j.jenvman.2019.07.017

Cited by 142 publications

(40 citation statements)

References 85 publications

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“…CQDs present an important class of carbon materials since their discovery in 2004 by Xu et al [116], with varying sizes in the range of 1-10 nm. They are good materials for photocatalytic applications due to features, like superiority in chemical stability and low toxicity [117]. Pan et al synthesized he 2D carbon quantum dots modified porous g-C 3 N 4 /TiO 2 nano-heterojunction [91] and reached 6.497 µmol/h/g of produced H 2 with the full spectrum absorption.…”

Section: Tio 2 /G-c 3 Nmentioning

confidence: 99%

“…MoS 2 represents two-dimensional transition metal dichalcogenide (TMD) that can be prepared into ultrathin-layered structures and, thus, participates in the H 2 evolution reaction as an effective non-noble metal alternative [117,146]. Without the use of any sacrificial agent and co-catalyst, Huang et al [146] observed photocatalytic H 2 generation while using MoS 2 quantum dots@TiO 2 nanotube arrays nanocomposite in pure water under visible light.…”

Section: Tio 2 /Mosmentioning

confidence: 99%

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Recent Achievements in Development of TiO2-Based Composite Photocatalytic Materials for Solar Driven Water Purification and Water Splitting

et al. 2020

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Clean water and the increased use of renewable energy are considered to be two of the main goals in the effort to achieve a sustainable living environment. The fulfillment of these goals may include the use of solar-driven photocatalytic processes that are found to be quite effective in water purification, as well as hydrogen generation. H2 production by water splitting and photocatalytic degradation of organic pollutants in water both rely on the formation of electron/hole (e−/h+) pairs at a semiconducting material upon its excitation by light with sufficient photon energy. Most of the photocatalytic studies involve the use of TiO2 and well-suited model compounds, either as sacrificial agents or pollutants. However, the wider application of this technology requires the harvesting of a broader spectrum of solar irradiation and the suppression of the recombination of photogenerated charge carriers. These limitations can be overcome by the use of different strategies, among which the focus is put on the creation of heterojunctions with another narrow bandgap semiconductor, which can provide high response in the visible light region. In this review paper, we report the most recent advances in the application of TiO2 based heterojunction (semiconductor-semiconductor) composites for photocatalytic water treatment and water splitting. This review article is subdivided into two major parts, namely Photocatalytic water treatment and Photocatalytic water splitting, to give a thorough examination of all achieved progress. The first part provides an overview on photocatalytic degradation mechanism principles, followed by the most recent applications for photocatalytic degradation and mineralization of contaminants of emerging concern (CEC), such as pharmaceuticals and pesticides with a critical insight into removal mechanism, while the second part focuses on fabrication of TiO2-based heterojunctions with carbon-based materials, transition metal oxides, transition metal chalcogenides, and multiple composites that were made of three or more semiconductor materials for photocatalytic water splitting.

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Section: Tio 2 /G-c 3 Nmentioning

confidence: 99%

Section: Tio 2 /Mosmentioning

confidence: 99%

Recent Achievements in Development of TiO2-Based Composite Photocatalytic Materials for Solar Driven Water Purification and Water Splitting

et al. 2020

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“…This topic has been addressed in several review works such as Wang et al [28], Moniz et al [29], Yang et al [30], and Fajrina et al [31], who reported the synthesis and properties of different semiconductor-semiconductor heterojunctions. Moreover, Kandi et al [32] and Rao et al [33] gathered several references about the exceptional properties of using quantum dots to boost photocatalytic activity where the authors highlighted the quantum confinement effect of emitting multiple electrons, size-adjustable properties such as light absorption, and the benefits of quantum dot-semiconductor heterojunctions, especially in hydrogen production [34].…”

Section: Introductionmentioning

confidence: 99%

Unravelling the Mechanisms that Drive the Performance of Photocatalytic Hydrogen Production

2020

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The increasing interest and applications of photocatalysis, namely hydrogen production, artificial photosynthesis, and water remediation and disinfection, still face several drawbacks that prevent this technology from being fully implemented at the industrial level. The need to improve the performance of photocatalytic processes and extend their potential working under visible light has boosted the synthesis of new and more efficient semiconductor materials. Thus far, semiconductor–semiconductor heterojunction is the most remarkable alternative. Not only are the characteristics of the new materials relevant to the process performance, but also a deep understanding of the charge transfer mechanisms and the relationship with the process variables and nature of the semiconductors. However, there are several different charge transfer mechanisms responsible for the activity of the composites regardless the synthesis materials. In fact, different mechanisms can be carried out for the same junction. Focusing primarily on the photocatalytic generation of hydrogen, the objective of this review is to unravel the charge transfer mechanisms after the in-depth analyses of already reported literature and establish the guidelines for future research.

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“…Noble metal NPs can also improve the photocatalytic activity of TiO 2 due to their surface plasmon resonance (SPR) effect, allowing visible light activity [5][6][7][8]. The collective oscillation of electrons at the surface of metal NPs can be induced by light irradiation which results in the enhancement of the photocatalytic activity.…”

Section: Introductionmentioning

confidence: 99%

Visible light sensitization of TiO2/Ag/N nanostructures synthesized by microwave irradiation for oxidative degradation of organic dyes

et al. 2020

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The synthesis of photocatalysts for organic pollutants degradation is a topic of fundamental interest and practical importance, in particular if using green methodologies. In this study, Methyl Orange (MO) and Indigo Carmine (IC) photodegradation on composite TiO 2 nanostructures containing silver or nitrogen was examined. TiO 2 nanotubes (NTs), TiO 2 nanoparticles (NPs) and Ag NPs were prepared by microwave-assisted chemistry (MWAC) using different precursors. The photocatalysts were characterized by XRD, TEM, UV-Vis, BET, XPS and EIS techniques. The degradation rate of MO by the TiO 2 NTs@Ag NPs photocatalyst, under UV-Vis illumination, was about six times higher than that exhibited by the pristine TiO 2 NTs. Additionally, the photodegradation rate of MO on TiO 2 NTs@Ag NPs under visible light (λ ≥ 400 nm) was more than three times higher than pristine TiO 2 NTs irradiated with UV-Vis light. TiO 2 NPs prepared using a water-soluble titanium complex [TALH: Titanium(IV) bis(ammoniumlactato)dihydroxide] as precursor, presents high photodegradation rate for IC and MO under UV-Vis and only visible light irradiation. The presence of nitrogen in the TiO 2 NPs lead to lower band gap values, compared to pristine NTs, which may explain the visible light activity of this photocatalyst. Additionally, Mott-Schottky analysis gave information about the donor density and the absolute position of the flatband potential of the nanostructured TiO 2 thin film electrodes showing a correlation between those parameters and the photocatalytic observed activity. The present work also shows that a green methodology, such as MWAC, coupled to a mild water-soluble precursor, like TALH, may lead to its use in environmental remediation applications with direct utilization of solar light as a sustainable technology.

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Sustainable hydrogen production for the greener environment by quantum dots-based efficient photocatalysts: A review

Cited by 142 publications

References 85 publications

Recent Achievements in Development of TiO2-Based Composite Photocatalytic Materials for Solar Driven Water Purification and Water Splitting

Recent Achievements in Development of TiO2-Based Composite Photocatalytic Materials for Solar Driven Water Purification and Water Splitting

Unravelling the Mechanisms that Drive the Performance of Photocatalytic Hydrogen Production

Visible light sensitization of TiO2/Ag/N nanostructures synthesized by microwave irradiation for oxidative degradation of organic dyes

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