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1.
Environ Res ; 242: 117761, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38036214

RESUMO

This paper describes a simple phyto-remediation of feather-like silver/copper bi-matrix (BMs) was constructed by employing pommagrant waste peel (PWP) extract as crucial role of reducing agent and chelating agents. Numerous strategies, including UV-Visible, XRD, SEM-EDX, and TEM and BET isotherm were used to analysis the optical, structural, surface area and functional properties. Ag/Cu BPNMs of TEM characterization shows feather-like architectural features with constrained size and shape. The Ag/Cu co-catalytic nanoparticles have a particle size of 34-64 nm. The photocatalytic efficiency of Ag/Cu BMs was investigated using a garment dye, Congo red (CR), at successive time intervals under halogen lamp exposure. For Ag/Cu bimetallic nanoparticles, the photocatalytic degradation rate was recorded to be 100% after 40 min which is caused by adsorption of Congo red dye molecules on Ag/Cu and their degradation by reactive oxygen species (ROS). ROS are free hydroxyl radicals such as •OH and O2• ions that have high oxidizing capacity. The developed Ag/Cu BMs shown effective bacteriostatic action against many infections.


Assuntos
Vermelho Congo , Nanopartículas Metálicas , Animais , Cobre/química , Plumas , Espécies Reativas de Oxigênio , Vestuário , Nanopartículas Metálicas/química
2.
Int J Mol Sci ; 25(13)2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-39000196

RESUMO

The green and sustainable electrocatalytic conversion of nitrogen-containing compounds to ammonia is currently in high demand in order to replace the eco-unfriendly Haber-Bosch process. Model catalysts for the nitrate reduction reaction were obtained by electrodeposition of metal Co, Fe, and bimetallic Fe/Co nanoparticles from aqueous solutions onto a graphite substrate. The samples were characterized by the following methods: SEM, XRD, XPS, UV-vis spectroscopy, cyclic (and linear) voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. In addition, the determination of the electrochemically active surface was also performed for all electrocatalysts. The best electrocatalyst was a sample containing Fe-nanoparticles on the layer of Co-nanoparticles, which showed a Faradaic efficiency of 58.2% (E = -0.785 V vs. RHE) at an ammonia yield rate of 14.6 µmol h-1 cm-2 (at ambient condition). An opinion was expressed to elucidate the mechanism of coordinated electrocatalytic action of a bimetallic electrocatalyst. This work can serve primarily as a starting point for future investigations on electrocatalytic conversion reactions to ammonia using model catalysts of the proposed type.


Assuntos
Amônia , Cobalto , Ferro , Nanopartículas Metálicas , Nitratos , Oxirredução , Amônia/química , Catálise , Ferro/química , Nanopartículas Metálicas/química , Nitratos/química , Cobalto/química , Técnicas Eletroquímicas/métodos
3.
Angew Chem Int Ed Engl ; : e202409945, 2024 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-39031539

RESUMO

Metal halide perovskites (MHPs) have emerged as attractive candidates for producing green hydrogen via photocatalytic pathway. However, the presence of abundant defects and absence of efficient hydrogen evolution reaction (HER) active sites on MHPs seriously limit the solar-to-chemical (STC) conversion efficiency. Herein, to address this issue, we present a bi-functionalization strategy through decorating MHPs with a molecular molybdenum-sulfur-containing co-catalyst precursor. By virtue of the strong chemical interaction between lead and sulfur and the good dispersion of the molecular co-catalyst precursor in the deposition solution, a uniform and intimate decoration of the MHPs surface with lead sulfide (PbS) and amorphous molybdenum sulfide (MoSx) co-catalysts is obtained simultaneously. We show that the PbS co-catalyst can effectively passivate the Pb-related defects on the MHPs surface, thus retarding the charge recombination and promoting the charge transfer efficiency significantly. The amorphous MoSx co-catalyst further promotes the extraction of photogenerated electrons from MHPs and facilitates the HER catalysis. Consequently, drastically enhanced photocatalytic HER activities are obtained on representative MHPs through the synergistic functionalization of PbS and MoSx co-catalysts. A solar-to-chemical (STC) conversion efficiency of ca. 4.63% is achieved on the bi-functionalized FAPbBr3-xIx, which is among the highest values reported for MHPs.

4.
Nanotechnology ; 34(44)2023 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-37527631

RESUMO

We report the formation of Mo1-xWxO3-CdS (0 ≤ x ≤1) nanophotocatalysts by a combination of solid-state and solution-impregnation processes. The formation of 2D+1D heterostructured composite was revealed by electron microscopy and the structure of ternary co-catalyst and photocatalysts were confirmed by spectroscopic analyses. The H2evolution activity of the nanocomposites was assessed via photocatalytic splitting of water under the irradiation of visible light. All the nanocomposites studied here exhibit notable catalytic activity and good photostability using lactic acid as the sacrificial electron donor compared to a pristine compound. Among these nanocomposites, WO3-CdS shows superior activity with H2evolution rates of 15.19 mmolg-1h-1, 28 times higher than the pure CdS. The WO3-CdS photoactivity is not only superior among all the composites studied here but also highest among the reported WO3composite catalysts to date. The novel construction of the oxide-based nanocomposite photocatalyst shown here efficiently enhances the catalytic activity by effective separation of charge carriers and inhibits photocorrosion of CdS nanorods. The apparent quantum yield of the hydrogen evolution for WO3-CdS was found to be 8% in the visible spectral range. The disparity of the catalytic ability between MoO3and WO3and the variance among the compositions was unraveled through optical band-offset alignment with respect to CdS. Though the 2D+1D novel fabrication is common to all the composites, the difference in the type of band alignment MoO3(type-I) and WO3(type-II) with CdS plays a highly significant role in the co-catalytic activity.

5.
J Environ Sci (China) ; 132: 12-21, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37336602

RESUMO

In the present work, functional diamine groups into indium frameworks to synthesize cyclic carbonates from CO2 and epoxides with efficient catalytic activity in the absence of co-catalyst and solvent are reported for the first time. Crystalline porous materials (CPM)-5 modified with 1,2-phenylene diamine and ethylene diamine (CPM-5-PhDA and CPM-5-EDA), were prepared using a post-synthetic modification (PSM) method. The properties of the modified CPM-5 were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), N2-adsorption, scanning electron microscopy (SEM), CO2 adsorption, and temperature programmed desorption TPD methods. The presence of diamine groups as basic sites and indium Lewis acid sites in the framework structure were desirable for high catalytic activity. For a given catalyst weight, CPM-5-PhDA was the best candidate to appear with great catalytic activity and selectivity for the cycloaddition reaction at 100°C and 1 MPa CO2 under co-catalyst and solvent free conditions. CPM-5-PhDA also was found to afford large and bulky epoxides. The catalyst can be easily separated and reused five times without any decline in activity.


Assuntos
Dióxido de Carbono , Índio , Solventes , Dióxido de Carbono/química , Diaminas , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Compostos de Epóxi/química
6.
Nanotechnology ; 33(26)2022 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-35303734

RESUMO

Hematite (α-Fe2O3) photoanode suffers from significant photocarrier recombination and sluggish water oxidation kinetics for photoelectrochemical water splitting. To address these challenges, this work demonstrates the construction of dual co-catalysts modified Fe2O3nanorods photoanode by strategically incorporating CoPi and Co(OH)xfor photoelectrochemical water oxidation. The Fe2O3/CoPi/Co(OH)xnanorods photoanode exhibits the lowest ever turn-on potential of 0.4VRHE(versus reversible hydrogen electrode) and a photocurrent density of 0.55 mA cm-2at 1.23VRHE, 358% higher than that of pristine Fe2O3nanorods. The dual co-catalysts modification enhances the light-harvesting efficiency, surface photovoltage and hole transfer kinetics of the hybrid photoanode. The dual co-catalyst coupling also increases the carrier density and significantly reduces the depletion width (1.9 nm), resulting in improved conductivity and favorable band bending, boosting photogenerated hole transfer efficiency for water oxidation.

7.
Environ Res ; 206: 112631, 2022 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-34973199

RESUMO

TiO2 is a well-known semiconductor used widely in the photocatalyst field, but its photocatalytic applications are hampered by a fast electron-hole recombination rate and low visible light absorption due to a wide-band-gap energy. Herein, we present a simple, low cost, and green approach to obtain carbon dots from microalgae, namely microalgae-based carbon dots (MCDs), using an unprecedented microwave-assisted treatment. The MCDs were successfully decorated on the surface of TiO2 nanoparticles. The as-prepared composite exhibited a superior photodegradation of methylene blue, compared with pristine TiO2 (83% and 27%, respectively) under visible light irradiation. The MCDs in TiO2-MCDs serve as electron reservoirs to trap photoinduced electrons and as photosensitizers for the improvement of visible light absorption; both factors play an important role in the improvement of the TiO2 photocatalytic activity. Furthermore, the as-prepared composite photocatalyst also exhibits high photostability and recyclability during the photodegradation of methylene blue. Therefore, this work provides an original approach to the development of environmentally friendly and highly effective photocatalysts for the treatment of various organic pollutants, which can go a long way toward ensuring a safe and sustainable environment.


Assuntos
Microalgas , Nanopartículas , Carbono , Catálise , Fotólise , Titânio
8.
Chemistry ; 27(66): 16448-16460, 2021 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-34519374

RESUMO

At present, inefficient charge separation of single photocatalyst impedes the development of photocatalytic hydrogen evolution. In this work, the CoSX /NiCo-LDH core-shell co-catalyst was cleverly designed, which exhibit high activity and high stability of hydrogen evolution in anhydrous ethanol system when coupled with CdS. Under visible light (λ≥420 nm) irradiation, the 3 %Co/NiCo/CdS composite photocatalyst exhibits a surprisingly high photocatalytic hydrogen evolution rate of 20.67 mmol g-1 h-1 , which is 59 times than that of the original CdS. Continuous light for 20 h still showed good cycle stability. In addition, the 3 %Co/NiCo/CdS composite catalyst also shows good hydrogen evolution performance under the Na2 S/Na2 SO3 and lactic acid system. The fluorescence (PL), ultraviolet-visible diffuse reflectance (UV-vis) and photoelectrochemical tests show that the coupling of CdS and CoSX /NiCo-LDH not only accelerates the effective transfer of charges, but also greatly increases the absorption range of CdS to visible light. Therefore, the hydrogen evolution activity of the composite photocatalyst has been significantly improved. This work will provide new insights for the construction of new co-catalysts and the development of composite catalysts for hydrogen evolution in multiple systems.

9.
Environ Sci Technol ; 55(19): 13326-13334, 2021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34524793

RESUMO

The sluggish regeneration rate of FeII and low operating pH still restrict the wider application of classical Fenton process (FeII/H2O2) for practical water treatment. To overcome these challenges, we exploit the Mn-CNH co-catalyst to construct a solid-liquid interfacial Fenton reaction and accelerate the FeIII/FeII redox cycle at the interface for sustainably generating •OH from H2O2 activation. The Mn-CNH co-catalyst exhibits an excellent regeneration rate of FeII (∼65%) and a high tetracycline removal rate (Kobs) of 0.0541 min-1, which is 19.0 times higher than that of the FeII/H2O2 system (0.0027 min-1) at a near-neutral pH (pH ≈ 5.8), and it also attains 100% degradation of sulfamethoxazole, rhodamine B, and methyl orange. The cyclic mechanism of FeIII/FeII is further elucidated in an atomic scale by combining characterizations and density functional theory calculations, including FeaqIII specific adsorption and the electron-transfer process. Mn active sites can accumulate electrons from the matrix and adsorb FeaqIII to form Mn-Fe bonds at the solid-liquid interface, which accelerate electron transfer from Mn-CNH to FeaqIII and promote the regeneration of FeII at a wide pH range with a lower energy barrier. The regeneration rate of FeII in the Mn-CNH/FeII/H2O2 system outperforms the benchmark Fenton system and other typical metal nanomaterials, which has great potential to be widely applied in actual environment remediation.


Assuntos
Compostos Férricos , Peróxido de Hidrogênio , Catálise , Concentração de Íons de Hidrogênio , Oxirredução
10.
Ecotoxicol Environ Saf ; 212: 111975, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33550077

RESUMO

Natural chalcocite (NCC) was chosen as a co-catalyst for activation of persulfate (PS) to degrade organic contaminants in this study. A synergistic effect between NCC and ferrous ions (Fe2+) was found in catalyzing PS for degradation of orange G (OG). The main role of NCC in the NCC/Fe2+/PS system was to facilitate Fe3+ reduction back to Fe2+ and thus improve the stoichiometric efficiency of PS. The results of scavenging experiments and electron paramagnetic resonance tests proved that both sulfate and hydroxyl radicals were the primary reactive oxidants in the NCC/Fe2+/PS system. Twelve potential intermediate products of OG were identified, and the degradation pathway was proposed. Experiment parameters, such as NCC dose, Fe2+ concentration, initial pH, and the presence of anions (H2PO4‒ and Cl‒), all had important impacts on OG degradation. NCC had good reusability in synergistic activation of PS with Fe2+ for OG degradation for five cycles. This study demonstrated a natural sulfide mineral as an efficient co-catalyst towards PS activation for destruction of organic contaminants in water.


Assuntos
Poluentes Químicos da Água/química , Compostos Azo , Catálise , Radical Hidroxila , Ferro , Minerais , Oxidantes , Oxirredução , Sulfatos , Sulfetos , Poluentes Químicos da Água/análise
11.
Molecules ; 26(22)2021 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-34834053

RESUMO

The electrochemical reduction of carbon dioxide (CO2ER) is amongst one the most promising technologies to reduce greenhouse gas emissions since carbon dioxide (CO2) can be converted to value-added products. Moreover, the possibility of using a renewable source of energy makes this process environmentally compelling. CO2ER in ionic liquids (ILs) has recently attracted attention due to its unique properties in reducing overpotential and raising faradaic efficiency. The current literature on CO2ER mainly reports on the effect of structures, physical and chemical interactions, acidity, and the electrode-electrolyte interface region on the reaction mechanism. However, in this work, new insights are presented for the CO2ER reaction mechanism that are based on the molecular interactions of the ILs and their physicochemical properties. This new insight will open possibilities for the utilization of new types of ionic liquids. Additionally, the roles of anions, cations, and the electrodes in the CO2ER reactions are also reviewed.

12.
Angew Chem Int Ed Engl ; 60(5): 2541-2547, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33241666

RESUMO

Effective transfer and utilization of the photogenerated electrons are a key factor for achieving highly efficient H2 generation by photocatalytic water splitting. Apart from the activity of the co-catalyst, the interface between the co-catalyst and semiconductor is of particular importance. Guided by DFT calculations, single-atom (SA) Pt doped carbon nitride (CN) is successfully synthesized for use as the co-catalyst to the semiconducting CuS. The catalyst system (Pt1-CN@CuS) exhibits an enhanced photocatalytic performance for water splitting with a H2 production rate of 25.4 µmol h-1 and an apparent quantum yield (AQY) of 50.3 % under the illumination of LED-530. Solar-to-hydrogen (STH) conversion efficiency is calculated to be 0.5 % under AM 1.5 illumination. This is the very first investigation of SA as the co-catalyst, which decreases the overpotential of CN during the water splitting and lowers interfacial resistance of the catalyst/co-catalyst and co-catalyst/electrolyte.

13.
Angew Chem Int Ed Engl ; 60(34): 18876-18881, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34170591

RESUMO

Although being attractive materials for photoelectrochemical hydrogen evolution reaction (PEC HER) under neutral or acidic conditions, conjugated polymers still show poor PEC HER performance in alkaline medium due to the lack of water dissociation sites. Herein, we demonstrate that tailoring the polymer skeleton from poly(diethynylthieno[3,2-b]thiophene) (pDET) to poly(2,6-diethynylbenzo[1,2-b:4,5-b']dithiophene (pBDT) and poly(diethynyldithieno[3,2-b:2',3'-d]thiophene) (pDTT) in conjugated acetylenic polymers (CAPs) introduces highly efficient active sites for water dissociation. As a result, pDTT and pBDT, grown on Cu substrate, demonstrate benchmark photocurrent densities of 170 µA cm-2 and 120 µA cm-2 (at 0.3 V vs. RHE; pH 13), which are 4.2 and 3 times higher than that of pDET, respectively. Moreover, by combining DFT calculations and electrochemical operando resonance Raman spectroscopy, we propose that the electron-enriched Cß of the outer thiophene rings of pDTT are the water dissociation active sites, while the -C≡C- bonds function as the active sites for hydrogen evolution.

14.
Molecules ; 25(6)2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32245102

RESUMO

Ferrous ion co-catalyst enhancement of dilute-acid (DA) pretreatment of biomass is a promising technology for increasing the release of sugars from recalcitrant lignocellulosic biomass. However, due to the reductive status of ferrous ion and its susceptibility to oxidation with exposure to atmosphere, its effective application presumably requires anaerobic aqueous conditions created by nitrogen gas-purging, which adds extra costs. The objective of this study was to assess the effectiveness of oxidative iron ion, (i.e., ferric ion) as a co-catalyst in DA pretreatment of biomass, using an anaerobic chamber to strictly control exposure to oxygen during setup and post-pretreatment analyses. Remarkably, the ferric ions were found to be as efficient as ferrous ions in enhancing sugar release during DA pretreatment of biomass, which may be attributed to the observation that a major portion of the initial ferric ions were converted to ferrous during pretreatment. Furthermore, the detection of hydrogen peroxide in the liquors after DA/Fe ion pretreatment suggests that Fenton reaction chemistry was likely involved in DA/Fe ion pretreatments of biomass, contributing to the observed ferric and ferrous interchanges during pretreatment. These results help define the extent and specification requirements for applying iron ions as co-catalysts in DA pretreatments of biomass.


Assuntos
Biomassa , Compostos Férricos/química , Compostos Ferrosos/química , Lignina/química , Aerobiose , Anaerobiose , Catálise , Peróxido de Hidrogênio/química , Hidrólise , Ferro , Oxirredução , Oxigênio
15.
J Environ Manage ; 248: 109246, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31323456

RESUMO

Nano-size photocatalysts exhibit multifunctional properties that opened the door for improved efficiency in energy, environment, and health care applications. Among the diversity of catalyst Quantum dots are a class of nanomaterials having a particle size between 2 and 10 nm, showing unique optoelectrical properties that are limited to some of the metal, metal oxide, metal chalcogenides, and carbon-based nanostructures. These unique characteristics arise from either pristine or binary/ternary composites where noble metal/metal oxide/metal chalcogenide/carbon quantum dots are anchored on the surface of semiconductor photocatalyst. It emphasized that properties, as well as performance of photocatalytic materials, are greatly influenced by the choice of synthesis methods and experimental conditions. Among the chemical methods, photo-deposition, precipitation, and chemical reduction, are the three most influential synthesis approaches. Further, two types of quantum dots namely metal based and carbon-based materials have been highlighted. Based on the optical, electrical and surface properties, quantum dots based photocatalysts have been divided into three categories namely (a) photocatalyst (b) co-catalyst and (c) photo-sensitizer. They showed enhanced photocatalytic performance for hydrogen production under visible/UV-visible light irradiation. Often, pristine metal chalcogenides as well as metal/metal oxide/carbon quantum dots attached to a semiconductor particle exhibit enhanced the photocatalytic activity for hydrogen production through absorption of visible light. Alternatively, noble metal quantum dots, which provide plenty of defects/active sites facilitate continuous hydrogen production. For instance, production of hydrogen in the presence of sacrificial agents using metal chalcogenides, metal oxides, and coinage metals based catalysts such as CdS/MoS2 (99,000 µmol h-1g-1) TiO2-Ni(OH)2 (47,195 µmol h-1g-1) and Cu/Ag-TiO2 nanotubes (56,167 µmol h-1g-1) have been reported. Among the carbon-based nanostructures, graphitic C3N4 and carbon quantum dots composites displayed enhanced hydrogen gas (116.1 µmol h-1) production via overall water splitting. This review accounts recent findings on various chemical approaches used for quantum dots synthesis and their improved materials properties leading to enhanced hydrogen production particularly under visible light irradiation. Finally, the avenue to improve quantum efficiency further is proposed.


Assuntos
Grafite , Pontos Quânticos , Catálise , Hidrogênio , Semicondutores
16.
Chemistry ; 22(46): 16410-16414, 2016 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-27643616

RESUMO

A systematic study on the effects of Lewis or Brønsted acid co-catalysts in gold-catalyzed reactions was undertaken using representative reactions (O-, N-, and C-nucleophilic additions to alkynes). Through these reactions, it was demonstrated that an acidic co-catalyst can increase the catalyst turnover significantly, enabling practical reaction rates at competitive catalyst loadings (<1 mol %). Further investigation is currently underway to improve the understanding of the subtle principles underlying these experimental observations.

17.
Angew Chem Int Ed Engl ; 53(51): 14201-5, 2014 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-25327934

RESUMO

The high-pressure hydrogenation of commercially available anatase or anatase/rutile TiO2 powder can create a photocatalyst for H2 evolution that is highly effective and stable without the need for any additional co-catalyst. This activation effect cannot be observed for rutile; however, for anatase/rutile mixtures, a strong synergistic effect can be found (similar to results commonly observed for noble-metal-decorated TiO2). EPR and PL measurements indicated the intrinsic co-catalytic activation of anatase TiO2 to be due to specific defect centers formed during hydrogenation. These active centers can be observed specifically for high-pressure hydrogenation; other common reduction treatments do not result in this effect.

18.
J Colloid Interface Sci ; 672: 631-641, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-38865877

RESUMO

The sustainable generation of ammonia by photocatalytic nitrogen fixation under mild conditions is fascinating compared to conventional industrial processes. Nevertheless, owing to the low charge transfer efficiency, the insufficient light absorption capacity and limited active sites of the photocatalyst cause the difficult adsorption and activation of N2 molecules, thereby resulting in a low photocatalytic conversion efficiency. Herein, a novel bimetallic CoMoB nanosheets (CoMoB) co-catalyst modified carbon nitride with dual moiety defects (CN-TH3/3) Schottky junction photocatalyst is designed for photocatalytic nitrogen reduction reaction (NRR). The photocatalytic nitrogen reduction rate of the optimized CoMoB/CN-TH3/3 photocatalyst is 4.81 mM·g-1·h-1, which is 6.2 and 2.2 times higher than carbon nitride (CN) (0.78 mM·g-1·h-1) and CN-TH3/3 (2.21 mM·g-1·h-1), respectively. The excellent photocatalytic NRR performance is ascribed not only to the introduction of dual moiety defects (cyano and cyanamide groups) that extends the visible light absorption range and promotes exciton polarization dissociation, but also to the formation of interfacial electric field between CoMoB and CN-TH3/3, which effectively facilitates the interfacial charge transfer. Thus, the synergistic interaction between CN-TH3/3 and CoMoB further increases the electron numble of CoMoB active sites, which effectively strengthens the adsorption and activation of N2 and weakens the NN triple bond, thereby enhancing the photocatalytic NRR activity. This work highlights the introduced dual moiety defects and bimetallic CoMoB co-catalyst to synergistically enhance the photocatalytic nitrogen reduction performance.

19.
ACS Nano ; 18(19): 12524-12536, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38687979

RESUMO

Highly active and low-cost co-catalysts have a positive effect on the enhancement of solar H2 production. Here, we employ two-dimensional (2D) MBene as a noble-metal-free co-catalyst to boost semiconductor for photocatalytic H2 production. MoB MBene is a 2D nanoboride, which is directly made from MoAlB by a facile hydrothermal etching and manual scraping off process. The as-synthesized MoB MBene with purity >95 wt % is treated by ultrasonic cell pulverization to obtain ultrathin 2D MoB MBene nanosheets (∼0.61 nm) and integrated with CdS via an electrostatic interaction strategy. The CdS/MoB composites exhibit an ultrahigh photocatalytic H2 production activity of 16,892 µmol g-1 h-1 under visible light, surpassing that of pure CdS by an exciting factor of ≈1135%. Theoretical calculations and various measurements account for the high performance in terms of Gibbs free energy, work functions, and photoelectrochemical properties. This work discovers the huge potential of these promising 2D MBene family materials as high-efficiency and low-cost co-catalysts for photocatalytic H2 production.

20.
J Colloid Interface Sci ; 662: 928-940, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38382376

RESUMO

The development of low-cost and efficient metal sulfide photocatalysts through morphological and structural design is vital to the advancement of the hydrogen economy. However, metal sulfide semiconductor photocatalysts still suffer from low carrier separation and poor solar-to-hydrogen conversion efficiencies. Herein, two-dimensional ZnIn2S4 nanosheets were grown on Zn0.5Cd0.5S hollow nanocages to construct Zn0.5Cd0.5S@ZnIn2S4 hollow nanocages for the first time. Novel hollow core-shell Zn0.5Cd0.5S@ZnIn2S4/MoS2 nanocages with Z-scheme heterojunction structures were obtained by incorporating MoS2 nanosheet co-catalyst via the solvothermal method. The resulting Zn0.5Cd0.5S@ZnIn2S4/MoS2 exhibited unique structural and compositional advantages, leading to remarkable photocatalytic hydrogen evolution rates of up to 8.5 mmol·h-1·g-1 without the use of any precious metal co-catalysts. This rate was 10.6-fold and 7.1-fold higher compared to pure ZnIn2S4 and Zn0.5Cd0.5S, respectively. Moreover, the optimized Zn0.5Cd0.5S@ZnIn2S4/MoS2 photocatalyst outperformed numerous reported ZnIn2S4-based photocatalysts and some ZnIn2S4-based photocatalysts based on precious metal co-catalysts. The exceptional photocatalytic performance of Zn0.5Cd0.5S@ZnIn2S4/MoS2 can be attributed to the Z-scheme heterojunction of core-shell structure that enhanced charge carrier separation and transport, as well as the co-catalytic action of MoS2. Overall, the proposed Zn0.5Cd0.5S@ZnIn2S4/MoS2 with heterojunction structure is a promising candidate for the preparation of efficient photocatalysts for solar-to-hydrogen energy conversion.

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