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2022 Volume 41 Issue 8
2022, 41(8): 220800
doi: 10.14102/j.cnki.0254-5861.2022-0129
Abstract:
The carbon nitride supported Fe SAC (Fe1/CN) catalyst with an Fe loading of 11.2 wt% tends to adsorb the terminal O of peroxymonosulfate (PMS) on Fe-N4 sites. Consequently, the Fe1/CN can efficiently activate PMS to generate singlet oxygen (1O2) with 100% selectivity and further boost the degradation of p-chlorophenol (4-CP).![]()
2022, 41(8): 220800
doi: 10.14102/j.cnki.0254-5861.2022-0125
Abstract:
In electrocatalysis, the stability issue between catalyst and support still needs great attention. Here, a series of high-entropy alloy nanoparticles (HEA-NPs) embedded in carbon cloth (CC) were synthesized by using the scalable strategy-microwave heating. Among them, PtRhCoNiCu/CC exhibits outstanding hydrogen evolution reaction (HER) activity (19 and 170 mV overpotential at 10 and 1000 mA cm-2) and stability (150 h), outperforming other recently reported HEAs catalysts. IrRuCoNiCu/CC displays superior oxygen evolution reaction (OER) activity (166 and 354 mV overpotential at 10 and 1000 mA cm-2) and stability (150 h), and shows a lower overpotential than recently reported HEA catalysts. In water splitting, IrRuCoNiCu/CC(+)//PtRhCoNiCu/CC(-) electrolyzer achieves 500 mA cm-2 (1000 mA cm-2) high current density at 1.76 V (1.88 V) and exhibits excellent stability, which is one of the best catalysts currently. Therefore, the novel supported HEA catalyst with high stability is expected to be a promising candidate material for industrialized water splitting.
In electrocatalysis, the stability issue between catalyst and support still needs great attention. Here, a series of high-entropy alloy nanoparticles (HEA-NPs) embedded in carbon cloth (CC) were synthesized by using the scalable strategy-microwave heating. Among them, PtRhCoNiCu/CC exhibits outstanding hydrogen evolution reaction (HER) activity (19 and 170 mV overpotential at 10 and 1000 mA cm-2) and stability (150 h), outperforming other recently reported HEAs catalysts. IrRuCoNiCu/CC displays superior oxygen evolution reaction (OER) activity (166 and 354 mV overpotential at 10 and 1000 mA cm-2) and stability (150 h), and shows a lower overpotential than recently reported HEA catalysts. In water splitting, IrRuCoNiCu/CC(+)//PtRhCoNiCu/CC(-) electrolyzer achieves 500 mA cm-2 (1000 mA cm-2) high current density at 1.76 V (1.88 V) and exhibits excellent stability, which is one of the best catalysts currently. Therefore, the novel supported HEA catalyst with high stability is expected to be a promising candidate material for industrialized water splitting.
2022, 41(8): 220801
doi: 10.14102/j.cnki.0254-5861.2022-0127
Abstract:
Metal-organic polyhedra (MOPs) have emerged as novel porous platforms for proton conduction, however, the concerted employment of both linker and metal cluster vertex is rarely applied for the fabrication of MOPs-based high conducting materials. Herein we report the synthesis of sulfonate-functionalized polyoxovanadate-based MOPs for enhanced proton conduction via the synergistic effect from linker and metal cluster node. MOPs 1 and 2 exhibit octahedral cage configuration constructed from {V5O9Cl} vertex and 5-sulfoisophthalate linker. Owing to the ordered packing of octahedral cages along three axes, 3D interpenetrated open channels that are lined with high-density sulfonates are thus formed within 2. Coupled with the proton-conductive {V5O9Cl} vertexs as well as protonated counterions, an extensive H-bonded network is therefore generated for facile proton transfer. 2 exhibits high proton conductivity of 3.02×10-2 S cm-1 at 65 ℃ under 90% RH, recording the highest value for MOPs pellet sample. This value is enhanced ~1 order of magnitude compared with that of carboxylate-functionalized analogue 3, clearly illustrating the advantage of combining linker and metal cluster node for enhanced proton conduction. This work will further promote the exploitation of high proton conductive MOPs-based materials by the synergy design strategy.
Metal-organic polyhedra (MOPs) have emerged as novel porous platforms for proton conduction, however, the concerted employment of both linker and metal cluster vertex is rarely applied for the fabrication of MOPs-based high conducting materials. Herein we report the synthesis of sulfonate-functionalized polyoxovanadate-based MOPs for enhanced proton conduction via the synergistic effect from linker and metal cluster node. MOPs 1 and 2 exhibit octahedral cage configuration constructed from {V5O9Cl} vertex and 5-sulfoisophthalate linker. Owing to the ordered packing of octahedral cages along three axes, 3D interpenetrated open channels that are lined with high-density sulfonates are thus formed within 2. Coupled with the proton-conductive {V5O9Cl} vertexs as well as protonated counterions, an extensive H-bonded network is therefore generated for facile proton transfer. 2 exhibits high proton conductivity of 3.02×10-2 S cm-1 at 65 ℃ under 90% RH, recording the highest value for MOPs pellet sample. This value is enhanced ~1 order of magnitude compared with that of carboxylate-functionalized analogue 3, clearly illustrating the advantage of combining linker and metal cluster node for enhanced proton conduction. This work will further promote the exploitation of high proton conductive MOPs-based materials by the synergy design strategy.
2022, 41(8): 220801
doi: 10.14102/j.cnki.0254-5861.2022-0050
Abstract:
One-dimensional nanostructures (1D) with short ion diffusion distance and fast ion transport path are excellent for lithium-ion batteries (LIBs). However, the nature of layered transition metal dichalcogenides makes it difficult to form 1D nanohybrids. Here, the MoTe2 nanorods with an average diameter of 100-200 nm and length of 1-3 μm encapsulated by reduced graphene oxide (MoTe2/rGO) have been fabricated via in-situ reaction of GO coated Mo3O10(C2H10N2) nanowires with Te under Ar/H2 atmosphere. When applied as anode of LIBs, the MoTe2/rGO delivers a high reversible capacity (637 mA h g-1 after 100 cycles at 0.2 A g-1), good rate capability (374 mA h g-1 at 2 A g-1) and excellent stability (360 mA h g-1 after 200 cycles at 0.5 A g-1), which surpasses bare MoTe2 nanorods and bulk MoTe2 crystallite. Furthermore, a lithium-ion full cell constructed by coupling MoTe2/rGO anode and LiCoO2 cathode shows a capacity of 105 mA h g-1 at 0.1 C. The enhanced performance mainly benefits from the advantages of 1D nanostructure, and meanwhile the rGO thin layers are able to improve the conductivity and maintain the structural stability. This work provides a simple pathway for the synthesis of 1D TMDs nanostructures for energy storage and conversion.
One-dimensional nanostructures (1D) with short ion diffusion distance and fast ion transport path are excellent for lithium-ion batteries (LIBs). However, the nature of layered transition metal dichalcogenides makes it difficult to form 1D nanohybrids. Here, the MoTe2 nanorods with an average diameter of 100-200 nm and length of 1-3 μm encapsulated by reduced graphene oxide (MoTe2/rGO) have been fabricated via in-situ reaction of GO coated Mo3O10(C2H10N2) nanowires with Te under Ar/H2 atmosphere. When applied as anode of LIBs, the MoTe2/rGO delivers a high reversible capacity (637 mA h g-1 after 100 cycles at 0.2 A g-1), good rate capability (374 mA h g-1 at 2 A g-1) and excellent stability (360 mA h g-1 after 200 cycles at 0.5 A g-1), which surpasses bare MoTe2 nanorods and bulk MoTe2 crystallite. Furthermore, a lithium-ion full cell constructed by coupling MoTe2/rGO anode and LiCoO2 cathode shows a capacity of 105 mA h g-1 at 0.1 C. The enhanced performance mainly benefits from the advantages of 1D nanostructure, and meanwhile the rGO thin layers are able to improve the conductivity and maintain the structural stability. This work provides a simple pathway for the synthesis of 1D TMDs nanostructures for energy storage and conversion.
2022, 41(8): 220802
doi: 10.14102/j.cnki.0254-5861.2022-0086
Abstract:
Photoelectrochemical (PEC) hydrogen production from water splitting is a green technology to convert solar energy into renewable hydrogen fuel. The construction of host/guest architecture in semiconductor photoanodes has been proven to be an effective strategy to improve solar-to-fuel conversion efficiency. In this study, WO3@Fe2O3 core-shell nanoarray heterojunction photoanodes are synthesized from the in-situ decomposition of WO3@Prussian blue (WO3@PB) and then used as host/guest photoanodes for photoelectrochemical water splitting, during which Fe2O3 serves as guest material to absorb visible solar light and WO3 can act as host scaffolds to collect electrons at the contact. The prepared WO3@Fe2O3 shows the enhanced photocurrent density of 1.26 mA cm-2 (under visible light) at 1.23 V. vs RHE and a superior IPEC of 24.4% at 350 nm, which is higher than that of WO3@PB and pure WO3 (0.43 mA/cm-2 and 16.3%, 0.18 mA/cm-2 and 11.5%) respectively, owing to the efficient light-harvesting from Fe2O3 and the enhanced electron-hole pairs separation from the formation of type-II heterojunctions, and the direct and ordered charge transport channels from the one-dimensional (1D) WO3 nanoarray nanostructures. Therefore, this work provides an alternative insight into the construction of sustainable and cost-effective photoanodes to enhance the efficiency of the solar-driven water splitting.
Photoelectrochemical (PEC) hydrogen production from water splitting is a green technology to convert solar energy into renewable hydrogen fuel. The construction of host/guest architecture in semiconductor photoanodes has been proven to be an effective strategy to improve solar-to-fuel conversion efficiency. In this study, WO3@Fe2O3 core-shell nanoarray heterojunction photoanodes are synthesized from the in-situ decomposition of WO3@Prussian blue (WO3@PB) and then used as host/guest photoanodes for photoelectrochemical water splitting, during which Fe2O3 serves as guest material to absorb visible solar light and WO3 can act as host scaffolds to collect electrons at the contact. The prepared WO3@Fe2O3 shows the enhanced photocurrent density of 1.26 mA cm-2 (under visible light) at 1.23 V. vs RHE and a superior IPEC of 24.4% at 350 nm, which is higher than that of WO3@PB and pure WO3 (0.43 mA/cm-2 and 16.3%, 0.18 mA/cm-2 and 11.5%) respectively, owing to the efficient light-harvesting from Fe2O3 and the enhanced electron-hole pairs separation from the formation of type-II heterojunctions, and the direct and ordered charge transport channels from the one-dimensional (1D) WO3 nanoarray nanostructures. Therefore, this work provides an alternative insight into the construction of sustainable and cost-effective photoanodes to enhance the efficiency of the solar-driven water splitting.
2022, 41(8): 220803
doi: 10.14102/j.cnki.0254-5861.2022-0112
Abstract:
Exploring bifunctional electrocatalysts with high-efficiency and stability toward overall water splitting is desirable for sustainable energy technologies, yet challenging. Herein, we report the construction of Ni3N on the surface of Ni-MOF-74 through an in-situ nitriding process. The obtained Ni-MOF-74/Ni3N exhibits remarkable HER activity with an overpotential of 73 mV to deliver 10 mA cm−2. Theoretical calculations and experimental study demonstrate the electron transport between Ni3N and Ni-MOF-74, leading to the improved H2O adsorption, optimized hydrogen adsorption, and increased Had diffusion, which contributes to the enhanced HER performance. Besides, the obtained Ni-MOF-74/Ni3N also possesses outstanding activity toward OER and overall water splitting.
Exploring bifunctional electrocatalysts with high-efficiency and stability toward overall water splitting is desirable for sustainable energy technologies, yet challenging. Herein, we report the construction of Ni3N on the surface of Ni-MOF-74 through an in-situ nitriding process. The obtained Ni-MOF-74/Ni3N exhibits remarkable HER activity with an overpotential of 73 mV to deliver 10 mA cm−2. Theoretical calculations and experimental study demonstrate the electron transport between Ni3N and Ni-MOF-74, leading to the improved H2O adsorption, optimized hydrogen adsorption, and increased Had diffusion, which contributes to the enhanced HER performance. Besides, the obtained Ni-MOF-74/Ni3N also possesses outstanding activity toward OER and overall water splitting.
2022, 41(8): 220803
doi: 10.14102/j.cnki.0254-5861.2022-0130
Abstract:
Integrating the advantages of anion vacancies and heterostructures into the catalytic materials may increase the binding affinities to intermediates, provide more active sites, and significantly promote the activity of overall water splitting. However, the successful assembly of anion vacancies and heterostructures for high-efficiency water splitting performance is still challenging. In this work, we ingeniously present the co-construction of sulfur vacancies and heterogeneous interface into Ni3S2/MoS2 catalysts on nickel foam (NF). The introduction of sulfur vacancies and Ni3S2/MoS2 heterostructures can significantly improve electron and ion transport, effectively improve structural stability, and enhance overall water splitting activity. The obtained VS-Ni3S2/MoS2 catalysts (VS stands for sulfur vacancies) exhibit superior OER and HER activities, and the overpotentials for OER and HER are 180 and 71 mV at 10 mA·cm-2, respectively. Furthermore, a low water splitting voltage of 1.46 V is required at 10 mA·cm-2 for the VS-Ni3S2/MoS2 catalysts, which is considerably lower than most that of water splitting electrocatalysts currently reported. This work offers an effective mean for the preparation of catalysts with both anion vacancies and heterostructures for achieving high-performance alkaline overall water splitting.
Integrating the advantages of anion vacancies and heterostructures into the catalytic materials may increase the binding affinities to intermediates, provide more active sites, and significantly promote the activity of overall water splitting. However, the successful assembly of anion vacancies and heterostructures for high-efficiency water splitting performance is still challenging. In this work, we ingeniously present the co-construction of sulfur vacancies and heterogeneous interface into Ni3S2/MoS2 catalysts on nickel foam (NF). The introduction of sulfur vacancies and Ni3S2/MoS2 heterostructures can significantly improve electron and ion transport, effectively improve structural stability, and enhance overall water splitting activity. The obtained VS-Ni3S2/MoS2 catalysts (VS stands for sulfur vacancies) exhibit superior OER and HER activities, and the overpotentials for OER and HER are 180 and 71 mV at 10 mA·cm-2, respectively. Furthermore, a low water splitting voltage of 1.46 V is required at 10 mA·cm-2 for the VS-Ni3S2/MoS2 catalysts, which is considerably lower than most that of water splitting electrocatalysts currently reported. This work offers an effective mean for the preparation of catalysts with both anion vacancies and heterostructures for achieving high-performance alkaline overall water splitting.
2022, 41(8): 220804
doi: 10.14102/j.cnki.0254-5861.2022-0141
Abstract:
Designing simple, efficient, and environmentally friendly methods to construct high-efficient photocatalysts is an important strategy to promote the further development of the field of photocatalysis. Herein, flower-like carbon quantum dots (CQDs)/BiOBr composite photocatalysts have been prepared via in-situ synthesis by mechanical ball milling in the existence of ionic liquid. The CQDs/BiOBr composites exhibit higher photo-degradation performance for tetracycline (TC) than BiOBr monomer and the commercial Bi2O3 under visible light irradiation. For comparison, the different Br sources and synthetic methods are chosen to prepare BiOBr and CQDs/BiOBr composites. Photocatalysts prepared by ball milling and ionic liquid present significantly enhanced photocatalytic performance for removing TC. In addition, the introduction of CQDs could distinctly enhance the photocatalytic performances of pure BiOBr. The reason is that CQDs as electron acceptor effectively separate electrons and holes and inhibit their recombination. The intermediates during photocatalytic degradation were tested using liquid chromatography-mass spectrometry (LC-MS) and possible degradation pathways were given. During degradation, •OH, O2•- and h+ were identified to be the main active species based on electron spin resonance (ESR) spectra and free radical trapping experiments. A possible mechanism of CQDs/BiOBr with enhanced photocatalytic performances was further proposed.
Designing simple, efficient, and environmentally friendly methods to construct high-efficient photocatalysts is an important strategy to promote the further development of the field of photocatalysis. Herein, flower-like carbon quantum dots (CQDs)/BiOBr composite photocatalysts have been prepared via in-situ synthesis by mechanical ball milling in the existence of ionic liquid. The CQDs/BiOBr composites exhibit higher photo-degradation performance for tetracycline (TC) than BiOBr monomer and the commercial Bi2O3 under visible light irradiation. For comparison, the different Br sources and synthetic methods are chosen to prepare BiOBr and CQDs/BiOBr composites. Photocatalysts prepared by ball milling and ionic liquid present significantly enhanced photocatalytic performance for removing TC. In addition, the introduction of CQDs could distinctly enhance the photocatalytic performances of pure BiOBr. The reason is that CQDs as electron acceptor effectively separate electrons and holes and inhibit their recombination. The intermediates during photocatalytic degradation were tested using liquid chromatography-mass spectrometry (LC-MS) and possible degradation pathways were given. During degradation, •OH, O2•- and h+ were identified to be the main active species based on electron spin resonance (ESR) spectra and free radical trapping experiments. A possible mechanism of CQDs/BiOBr with enhanced photocatalytic performances was further proposed.
2022, 41(8): 220805
doi: 10.14102/j.cnki.0254-5861.2022-0143
Abstract:
Developing efficient and promising non-noble catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is vital but still a huge challenge for the clean energy system. Herein, we have integrated the active components for OER (Ni(OH)2) and HER (NiS2 and Ni(OH)2) into Ni(OH)2@NiS2 heterostructures by a facile reflux method. The in-situ formed Ni(OH)2 thin layer is coated on the surface of hollow NiS2 nanosphere. The uniform Ni(OH)2@NiS2 hollow sphere processes enlarge the electrochemically active specific surface area and enhance the intrinsic activity compared to NiS2 precursor, which affords a current density of 10 mA cm-2 at the overpotential of 309 mV and 100 mA cm-2 at 359 mV for OER. Meanwhile, Ni(OH)2@NiS2 can reach 10 mA cm-2 at 233 mV for HER, superior to pure NiS2. The enhanced performance can be attributed to the synergy between Ni(OH)2 and NiS2. Specifically, Ni(OH)2 has three functions for water splitting: providing active sites for hydrogen adsorption and hydroxyl group desorption and working as real OER active sites. Moreover, Ni(OH)2@NiS2 displays great stability for OER (50 h) and HER (30 h).
Developing efficient and promising non-noble catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is vital but still a huge challenge for the clean energy system. Herein, we have integrated the active components for OER (Ni(OH)2) and HER (NiS2 and Ni(OH)2) into Ni(OH)2@NiS2 heterostructures by a facile reflux method. The in-situ formed Ni(OH)2 thin layer is coated on the surface of hollow NiS2 nanosphere. The uniform Ni(OH)2@NiS2 hollow sphere processes enlarge the electrochemically active specific surface area and enhance the intrinsic activity compared to NiS2 precursor, which affords a current density of 10 mA cm-2 at the overpotential of 309 mV and 100 mA cm-2 at 359 mV for OER. Meanwhile, Ni(OH)2@NiS2 can reach 10 mA cm-2 at 233 mV for HER, superior to pure NiS2. The enhanced performance can be attributed to the synergy between Ni(OH)2 and NiS2. Specifically, Ni(OH)2 has three functions for water splitting: providing active sites for hydrogen adsorption and hydroxyl group desorption and working as real OER active sites. Moreover, Ni(OH)2@NiS2 displays great stability for OER (50 h) and HER (30 h).
2022, 41(8): 220805
doi: 10.14102/j.cnki.0254-5861.2022-0151
Abstract:
Rational design and controllable synthesis of visible-light-responsive photocatalysts that exhibit both good hydrogen-producing efficiency and stability in the water splitting reaction are undoubtedly a challenge. Here we report an integrated CdS nanorod/oxygen-terminated Ti3C2Tx MXene nanosheet heterojunction with a high catalytic hydrogen evolution reaction (HER) activity. By incorporating one-dimensional (1D) CdS nanorods onto annealed ultrathin two-dimensional (2D) MXene nanosheets, the mixed-dimensional 1D/2D heterojunction achieved a hydrogen-evolving rate of 8.87 mmol⋅g-1⋅h-1, much higher than that of bulk CdS and CdS/unmodified MXene hybrid catalysts. The enhanced HER activity and stability of the designed heterojunction catalyst are attributed to the presence of oxygen-containing terminal groups on the surface of thermally treated Ti3C2Tx MXene, extended light absorption spectra as well as the precisely constructed intimate Schottky contact, implying an accelerated interfacial charge transfer and efficient, long-term photocatalytic hydrogen production performance. The results demonstrate that oxygen-terminated 2D MXene can be well utilized as a functional platform for the development of novel heterojunction photocatalysts.
Rational design and controllable synthesis of visible-light-responsive photocatalysts that exhibit both good hydrogen-producing efficiency and stability in the water splitting reaction are undoubtedly a challenge. Here we report an integrated CdS nanorod/oxygen-terminated Ti3C2Tx MXene nanosheet heterojunction with a high catalytic hydrogen evolution reaction (HER) activity. By incorporating one-dimensional (1D) CdS nanorods onto annealed ultrathin two-dimensional (2D) MXene nanosheets, the mixed-dimensional 1D/2D heterojunction achieved a hydrogen-evolving rate of 8.87 mmol⋅g-1⋅h-1, much higher than that of bulk CdS and CdS/unmodified MXene hybrid catalysts. The enhanced HER activity and stability of the designed heterojunction catalyst are attributed to the presence of oxygen-containing terminal groups on the surface of thermally treated Ti3C2Tx MXene, extended light absorption spectra as well as the precisely constructed intimate Schottky contact, implying an accelerated interfacial charge transfer and efficient, long-term photocatalytic hydrogen production performance. The results demonstrate that oxygen-terminated 2D MXene can be well utilized as a functional platform for the development of novel heterojunction photocatalysts.
