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Journal ArticleDOI

Photocatalytic mineralization of hydrogen sulfide as a dual-phase technique for hydrogen production and environmental remediation

TL;DR: In this article, the performance of photocatalysts is evaluated in terms of quantum yield, space-time yield, and other operational variables, including mode of operation, irradiation time, and relative humidity.
Abstract: Hydrogen sulfide (H2S) is regarded as a broad-spectrum poison associated with severe health consequences. Among the available treatment options, photocatalytic technology may be effectively applied to the production of hydrogen gas through the splitting of H2S molecules and the addition of 79.9 kJ mol−1 of energy. As a result, advanced photo-reactive media may provide a win-win strategy to treat the parent pollutant (H2S) while producing hydrogen gas. This review encompasses both TiO2 and non-TiO2 catalysts capable of operating under ultraviolet, visible, and solar light irradiation. The performances of photocatalysts are assessed in terms of quantum yield, space-time yield, and other operational variables, including mode of operation, irradiation time, and relative humidity. The concept of space velocity is used to compare photocatalysts in reference to benchmark parameters for the treatment of H2S. This review addresses current limitations and future prospects of the application of photocatalytic technology to efficiently mitigate H2S pollution.
Citations
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Journal ArticleDOI
TL;DR: In this article, a review of the recent processes and advances on catalytic elimination of VOCs over nanoparticles catalysts is presented, and the perspectives to the scientific issues and challenges faced, as well as the future outlooks are proposed.
Abstract: Volatile organic compounds (VOCs) with the properties of volatility, toxicity and diffusivity pose a serious threat to human health and eco-environment. Catalytic oxidation technology has been considered as a highly efficient option for the treatment of VOCs. This review systematically summarizes the recent processes and advances on catalytic elimination of VOCs over nanoparticles catalysts. Firstly, catalytic performances of catalysts for VOC degradation are evaluated and compared on the basis of unified performance metrics. Secondly, catalytic mechanisms of VOC oxidation, based on experimental and theoretical studies, are systematically introduced. Then, catalytic reactors employed in VOC elimination processes are summarized. In particular, photothermocatalysis by integrating (thermo)catalysis with photocatalysis is also elucidated. Lastly, the perspectives to the scientific issues and challenges faced, as well as the future outlooks are proposed. Collectively, this review will provide theoretical and experimental foundation for rational fabrication and application of nanoparticles catalysts toward VOC elimination in future.

299 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the photocatalytic applications of COFs is presented, including heterogeneous photocatalysis, degradation and conversion of amines to imines under visible light irradiation.

104 citations

Journal ArticleDOI
TL;DR: In this article, the authors showed that the co-presence of toluene and acetone does not change the catalytic mechanism, and the reaction pathway for the oxidative removal of tolpoxide and acyclic acid in the mixture may follow the pathway for single tolpioxene or acetone.
Abstract: We prepare TiO2 nanosheet-supported Pt nanocatalysts with an average size of 1.3, 1.9, and 3.0 nm. Due to the great decrease in the adsorption ability for toluene and acetone, mutual inhibition is first observed over Pt1.9 nm/TiO2 for the catalytic removal of a toluene and acetone mixture. At 140 °C, the toluene and acetone reaction rate is 0.033 and 0.045 μmol/(gcat s), respectively, for the oxidation of 500 ppm toluene or acetone, which is much higher than the corresponding reaction rate (0.020 and 0.007 μmol/(gcat s)) for the oxidation of the mixture. Pt1.9 nm/TiO2 exhibits a good catalytic stability and H2O and CO2 tolerance. With strong evidence, we find that the co-presence of toluene and acetone does not change the catalytic mechanism, and the reaction pathway for the oxidative removal of toluene and acetone in the mixture may follow the pathway for the oxidation of single toluene or acetone.

101 citations

Journal ArticleDOI
TL;DR: In this article, a one-step confined template method is proposed to obtain high-quality 1 T MoS2 in the CuS nanoframe (CuS-MoS2-1 T).
Abstract: The large-scale synthesis of the metallic phase MoS2 (1 T MoS2) is important for enhancing the photocatalytic hydrogen evolution reaction (HER). However, it’s difficult to obtain a high-quality of 1 T MoS2, especially when integrated with other semiconductors for hetero nanomaterials. Herein, a one-step confined template method is proposed to obtain high-quality 1 T MoS2 in the CuS nanoframe (CuS–MoS2–1 T). During the synthesis, a unique porous Cu–Mo-based metal–organic framework (MOF), i.e., NENU-5 template has been adopted and in situ sulfurized, where 1 T MoS2 and CuS have been simultaneously obtained. Interestingly, we find that the confined pores of the CuS nanoframe inhibits the bulk growth of MoS2 to produce high-stability and large-scale 1 T MoS2 (a high concentration of ∼70 %). The obtained nanomaterial exhibits remarkable photocatalytic activity with the hydrogen production rate of approximately 9648.7 μmol g−1 h−1, which is much higher than other various newly developed photocatalysts reported early. This study develops a new strategy via MOF confined template for high-quality 1 T MoS2 production and achieves outstanding performance in the photocatalytic water splitting. This approach may also shed light on other similar confined templates for the praparation of high-quality metastable nanomaterials.

95 citations

References
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Journal ArticleDOI
07 Jul 1972-Nature
TL;DR: Water photolysis is investigated by exploiting the fact that water is transparent to visible light and cannot be decomposed directly, but only by radiation with wavelengths shorter than 190 nm.
Abstract: ALTHOUGH the possibility of water photolysis has been investigated by many workers, a useful method has only now been developed. Because water is transparent to visible light it cannot be decomposed directly, but only by radiation with wavelengths shorter than 190 nm (ref. 1).

27,819 citations

Journal ArticleDOI
TL;DR: In this article, the basic fundamental principles are described as well as the influence of the main parameters governing the kinetics (mass of catalyst, wavelength, initial concentration, temperature and radiant flux).

2,424 citations

Journal ArticleDOI
TL;DR: In this article, a review summarizes the basics of overall water splitting via both one-step excitation and Z-scheme processes, with a focus on standard methods of determining photocatalytic performance.
Abstract: Overall water splitting based on particulate photocatalysts is an easily constructed and cost-effective technology for the conversion of abundant solar energy into clean and renewable hydrogen energy on a large scale. This promising technology can be achieved in a one-step excitation system using a single photocatalyst or via a Z-scheme process based on a pair of photocatalysts. Ideally, such photocatalysis will proceed with charge separation and transport unaffected by recombination and trapping, and surface catalytic processes will not involve undesirable reactions. This review summarizes the basics of overall water splitting via both one-step excitation and Z-scheme processes, with a focus on standard methods of determining photocatalytic performance. Various surface engineering strategies applied to photocatalysts, such as cocatalyst loading, surface morphology control, surface modification and surface phase junctions, have been developed to allow efficient one-step excitation overall water splitting. In addition, numerous visible-light-responsive photocatalysts have been successfully utilized as H2-evolution or O2-evolution photocatalysts in Z-scheme overall water splitting. Prototype particulate immobilization systems with photocatalytic performances comparable to or drastically higher than those of particle suspension systems suggest the exciting possibility of the large-scale production of low-cost renewable solar hydrogen.

1,460 citations

Journal ArticleDOI
TL;DR: In this article, thin films of silicon-doped Fe2O3 were deposited by APCVD (atmospheric pressure chemical vapor deposition) from Fe(CO)5 and TEOS (tetraethoxysilane) on SnO2-coated glass at 415 °C.
Abstract: Thin films of silicon-doped Fe2O3 were deposited by APCVD (atmospheric pressure chemical vapor deposition) from Fe(CO)5 and TEOS (tetraethoxysilane) on SnO2-coated glass at 415 °C. HRSEM reveals a highly developed dendritic nanostructure of 500 nm thickness having a feature size of only 10−20 nm at the surface. Real surface area determination by dye adsorption yields a roughness factor of 21. XRD shows the films to be pure hematite with strong preferential orientation of the [110] axis vertical to the substrate, induced by silicon doping. Under illumination in 1 M NaOH, water is oxidized at the Fe2O3 electrode with higher efficiency (IPCE = 42% at 370 nm and 2.2 mA/cm2 in AM 1.5 G sunlight of 1000 W/m2 at 1.23 VRHE) than at the best reported single crystalline Fe2O3 electrodes. This unprecedented efficiency is in part attributed to the dendritic nanostructure which minimizes the distance photogenerated holes have to diffuse to reach the Fe2O3/electrolyte interface while still allowing efficient light abso...

1,442 citations

Journal ArticleDOI
TL;DR: An overview of the membrane technology in current use for natural gas treatment and outlines the future prospects can be found in this paper, with a focus on the membrane-based removal of natural gas contaminants.
Abstract: Every year, the world uses close to 100 trillion scf (standard cubic feet) of natural gas. All of this gas requires treatment before it enters the pipeline, making natural gas processing by far the largest market for industrial gas separation processes and equipment. Of this huge market, membranes have less than a 5% share, but this is changing; membrane-based removal of natural gas contaminants is growing faster than any other segment of the membrane gas separation business. This paper gives an overview of the membrane technology in current use for natural gas treatment and outlines the future prospects.

1,170 citations