Recent Advancements in Photocatalytic Valorization of Plastic Waste to Chemicals and Fuels

Chen, Aizhu; Yang, Min‐Quan; Wang, Sibo; Qian, Qingrong

doi:10.3389/fnano.2021.723120

Cited by 40 publications

(37 citation statements)

References 53 publications

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“…Due to the growing consumption of fossil fuels and consequent energy crisis and climate changes, considerable efforts have been exerted to seek alternatives for renewable energy. Hydrogen (H2) has been regarded as environmentfriendly and clean energy, which has motivated the exploration of various H2-producing technologies during the past decades [1][2][3][4][5] . Photocatalytic H2 evolution with semiconductor materials by virtue of abundant sunlight has become a promising strategy for renewable energy production without the release of hazardous substances [6][7][8][9][10] .…”

mentioning

confidence: 99%

Hollow NiCo2S4 Nanospheres as a Cocatalyst to Support ZnIn2S4 Nanosheets for Visible-Light-Driven Hydrogen Production

Xiong¹,

Hou²,

Yuan³

et al. 2021

Acta Physico Chimica Sinica

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The rational interface tailoring of nanosheets on hollow spheres is a promising strategy to develop efficient photocatalysts for hydrogen production with solar energy. Among the various photocatalyst materials, metal sulfides have been extensively researched because of their relatively narrow band gap and superior visible-light response. ZnIn2S4 is a layered ternary chalcogenide semiconductor photocatalyst with a tunable band gap energy (approximately 2.4 eV). Among various metal sulfide photocatalysts, ZnIn2S4 has gained considerable attention. However, intrinsic ZnIn2S4 only exhibits a relatively moderate photocatalytic activity, which is mainly owing to the high recombination and low migration rate of photocarriers. Loading cocatalysts onto semiconductor photocatalysts is an effective way to improve the performance of photocatalysts, because it can not only facilitate the separation of electron-hole pairs, but also reduce the activation energy for proton reduction. As a ternary transition metal sulfide, NiCo2S4 features a high electrical conductivity, low electronegativity, excellent redox properties, and outstanding electrocatalytic activity. Such favorable characteristics suggest that NiCo2S4 can expedite charge separation and transfer, thereby promoting photocatalytic H2 production by serving as a cocatalyst. Moreover, both NiCo2S4 and ZnIn2S4 possess the ternary spinel crystal structure, which may facilitate the construction of NiCo2S4/ZnIn2S4 hybrids with tight interfacial contact for an enhanced photocatalytic performance. Herein, ultrathin ZnIn2S4 nanosheets were grown in situ on a non-noble-metal cocatalyst, namely NiCo2S4 hollow spheres, to form hierarchical NiCo2S4@ZnIn2S4 hollow heterostructured photocatalysts with an intimately coupled interface and strong visible light absorption extending to ca. 583 nm. The optimized NiCo2S4@ZnIn2S4 hybrid with a NiCo2S4 content of ca. 3.1% exhibited a high hydrogen evolution rate of 78 μmol•h −1 , which was approximately 9 times higher than that of bare ZnIn2S4 and 3 times higher than that of 1% (w, mass fraction) Pt/ZnIn2S4. Additionally, the hybrid photocatalysts displayed good stability in the reaction. Photoluminescence and electrochemical analysis results indicated that NiCo2S4 hollow spheres served as an efficient cocatalyst for facilitating the separation and transport of light-induced charge carriers as well as reducing the hydrogen evolution reaction barrier. Finally, a possible reaction mechanism for the photocatalytic hydrogen evolution was proposed. In the NiCo2S4@ZnIn2S4 composite photocatalyst, the NiCo2S4 cocatalyst with high electrical conductivity favorably accepts the photoinduced electrons transferred from ZnIn2S4 and then employs the electrons to reduce protons for H2 production on the reactive sites. Concurrently, the photogenerated holes are trapped by TEOA that acts as a hole scavenger to accomplish the photoredox cycle. This study provides guidance for the fabrication of hierarchical hollow heterostructures based on nanosheet semiconducto...

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confidence: 99%

Hollow NiCo2S4 Nanospheres as a Cocatalyst to Support ZnIn2S4 Nanosheets for Visible-Light-Driven Hydrogen Production

Xiong¹,

Hou²,

Yuan³

et al. 2021

Acta Physico Chimica Sinica

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“…Meanwhile, the holes (h + ) located in the valence band migrate to the photocatalyst surface, which can directly oxidize plastics or react with H 2 O adsorbed to generate more •OH and degrade the plastic into a variety of small molecular organic compounds or eventually to CO 2 and H 2 O. [ 33,111 ] During the degradation process, the reactive oxygen species such as •OH are nonselective, which usually results in a complex mixture of products such as microplastics, nanoplastics, small organic fragments, and mineralized products. In general, the production of various reactive oxygen species and the photodegradation process of plastics are depicted below

\begin{matrix} Semiconductor (SC) + h v \to {normalh}_{(VB)}^{+} + {normale}_{(CB)}^{-} \end{matrix}

\begin{matrix} {normalh}_{(VB)}^{+} + {normalH}_{2} O \to \cdot OH + {normalH}^{+} \end{matrix}

\begin{matrix} {normale}_{(CB)}^{-} + {normalO}_{2} \to {normalO}_{2}^{\cdot -} \end{matrix}

\begin{matrix} {normalO}_{2}^{\cdot -} + {normale}_{(CB)}^{-} + 2 {normalH}^{+} \to {normalH}_{2} {normalO}_{2} \end{matrix}

\begin{matrix} {normalH}_{2} {normalO}_{2} + h v \to 2 \cdot OH \end{matrix}

…”

Section: Photodegradation Of Plastic Wastesmentioning

confidence: 99%

“…In recent years, upcycling catalytic methods for plastics conversion, such as thermocatalytic and photocatalytic routes, have received increasing attention because the plastic waste can be upgraded into valuable fuels, chemicals, or materials with additional economic benefits. [30][31][32][33][34][35][36] Compared to the thermochemical route, including pyrolysis and gasification, which generally require large energy inputs and harsh reaction conditions such as high temperature and pressure, photocatalysis is considered as a greener and cheaper technique owing to its mild conditions of ambient pressure and temperature using sunlight or artificial light (e.g., LEDs with low-energy consumption) as the energy source. [37][38][39][40][41][42] Furthermore, in contrast with the severe conditions applied during thermocatalysis, the mild process of photocatalysis has great potential for the precise activation of specific chemical bonds with other functional groups preserved, which can achieve high selectivity toward targeted products.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Conversion of Plastic Waste: From Photodegradation to Photosynthesis

Chu

Zhang

Zhao

et al. 2022

Advanced Energy Materials

123

106

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Plastic waste remains a global challenge due to the massive amounts being produced without satisfactory treatment technologies for recycling and upcycling. Photocatalytic processes are emerging as green and promising approaches to upcycle plastics into value‐added products under mild conditions using sunlight as the energy source. In this review, the recent advances in plastic conversion through photocatalysis have been comprehensively summarized. Special emphasis is placed on the photocatalytic mechanism and the selective CC and CH bond transformations of plastics to access fuels, chemicals, and materials. Finally, the challenges and the perspectives on establishing a new paradigm toward a sustainable and circular plastic economy are also put forward.

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“…Environmental treatment (plastic waste transformation, 208 domestic sewage treatment, 209,210 VOC, 76 factory exhaust desulfurization and denitrification, etc.) processes often require a large amount of energy, and the use of fossil energy makes these processes a source of carbon dioxide emissions 97 .…”

Section: Applications Of Single‐atom Catalysts In Carbon Neutralmentioning

confidence: 99%

Towards single‐atom photocatalysts for future carbon‐neutral application

Zhang

et al. 2022

SmartMat

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The implementation of carbon neutrality to achieve the goal of controlling global warming in the Paris Climate Agreement is currently the most important international climate issue. Efficient utilization of solar energy through photocatalysts is of great significance to the adjustment of energy structure. Single‐atom photocatalysts have excellent catalytic activity and selectivity in a variety of applications, including sustainable energy conversion, chemical synthesis, CO2 reduction, environmental remediation, and other areas, owing to their unique electronic structure and high atom usage. Here, we elaborated on the content and implementation direction of the carbon neutrality policy and demonstrated the design principles of single‐atom photocatalysts. Recent single‐atom synthesis strategies are summarized, and representative characterization methods have been shown to further reveal the structure–performance relationship. Then, we focus on the application of single‐atom photocatalysts in CO2 reduction, sustainable energy conversion, and environmental remediation. Finally, the opportunities and challenges in the application of single‐atom photocatalysts were discussed based on its current development.

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Recent Advancements in Photocatalytic Valorization of Plastic Waste to Chemicals and Fuels

Cited by 40 publications

References 53 publications

Hollow NiCo<sub>2</sub>S<sub>4</sub> Nanospheres as a Cocatalyst to Support ZnIn<sub>2</sub>S<sub>4</sub> Nanosheets for Visible-Light-Driven Hydrogen Production

Hollow NiCo<sub>2</sub>S<sub>4</sub> Nanospheres as a Cocatalyst to Support ZnIn<sub>2</sub>S<sub>4</sub> Nanosheets for Visible-Light-Driven Hydrogen Production

Photocatalytic Conversion of Plastic Waste: From Photodegradation to Photosynthesis

Towards single‐atom photocatalysts for future carbon‐neutral application

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