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NiSe as an effective co-catalyst coupled with TiO2 for enhanced photocatalytic hydrogen evolution
摘要： Construction of semiconductor heterojunctions can effectively accelerate the separation of photo-induced charge carriers and thereby enhance photocatalytic activity. Here, NiSe was used as an effective co-catalyst to construct an active NiSe/TiO2 heterojunction for improving the photocatalytic H2 production of TiO2. The resultant 10%NiSe/TiO2 heterojunction exhibited 11 times higher photocatalytic H2-production activity than that of bare TiO2. The NiSe/TiO2 heterojunction and the photo-reduction of partial Ni2t to Ni0 notably accelerated the separation and transfer of photo-excited electron-hole pairs, and thus resulted in obvious improvement of H2-evolution activity. This work holds promise for the application of NiSe in photocatalysis as a high-efficiency photocatalytic cocatalyst.
关键词： NiSe/TiO2,Photoreduction,Heterojunction,Metal Ni0,Photocatalytic H2 evolution
更新于2025-11-14 17:04:02
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Photocatalytic CO2 reduction on porous TiO2 synergistically promoted by atomic layer deposited MgO overcoating and photodeposited silver nanoparticles
摘要： In this work, a porous TiO2 photocatalyst derived from metal-organic framework MIL-125 was synthesized and tested for photocatalytic CO2 reduction with water. To improve the photocatalytic performance, innovative materials modifications were employed by decorating TiO2 with atomic layer deposited (ALD) MgO overcoating and photodeposited silver (Ag) nanoparticles at different orders: MgO deposition followed by Ag (i.e. Ag/MgO/TiO2), or Ag deposition followed by MgO (i.e. MgO/Ag/TiO2). The addition of Ag promoted transfer of photoinduced electrons, while the coating of an ultrathin MgO layer inhibited surface charge recombination and enhanced CO2 adsorption. The combination of MgO and Ag resulted in synergistic promotion on CO2 photoreduction greater than the sum of individual promotional effects. The Ag/MgO/TiO2 catalyst with 7 ALD-layers of MgO and 5% Ag was 14 times more active than the pristine TiO2 in terms of CO and CH4 production. In addition, the sequence of MgO/Ag decoration influenced the catalytic activity. The Ag/MgO/TiO2 catalysts were in general more active than the MgO/Ag/TiO2 counterparts, likely due to the different electron mobility and Ag nanoparticle distribution on the surface. This work for the first time reports the novel materials structure of ALD coated MgO and photodeposited Ag nanoparticles on TiO2, and it reveals the importance of optimizing materials morphology and structure to promote the catalytic activity.
关键词： CO2 photoreduction,magnesium oxide,silver nanoparticles,atomic layer deposition,porous TiO2
更新于2025-11-14 17:03:37
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Promoting Photoreduction Properties via Synergetic Utilization between Plasmonic Effect and Highly Active Facet of BiOCl
摘要： Exploring highly efficient photocatalysts is an urgent task for achieving efficient solar-to-chemical conversion. Plasmonic effect is widely used in improving the photocatalytic properties via reducing the activation barrier for chemical reactions, enhancing the absorption of the photocatalysts or injecting the hot carriers into the photocatalysts from the plasmon metals. In this work, we design BiOCl-Ag-E with Ag loaded on the edge side of BiOCl. This hybrid structure takes the advantages of highly photocatalytic active (001) facet of BiOCl and the plasmonic effect. The plasmon metal is proposed to provide the (001) facets with more photogenerated charge carriers driving by the internal electric field, which is convinced by the photocurrent response and the detection of active species. Due to the accumulation of more negative charge carriers on (001) facet, BiOCl-Ag-E presents outstanding waste-water cleaning and CO2 photoreduction properties. The methodology of material design in this work paves the way for future design of efficient photocatalysts.
关键词： photocatalyst,synergy effect,surface plasmon resonance,CO2 photoreduction,selective growth
更新于2025-11-14 15:27:09
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Oxygen-vacancies-engaged efficient carrier utilization for the photocatalytic coupling reaction
摘要： Defects can greatly optimize the solar light harvesting capability and electronic structure of oxide materials. However, it remains challenging to achieve a defect engineering strategy under mild conditions. Meanwhile, the simultaneous exploitation of photogenerated holes (h+) and electrons (e?) to promote both photooxidation and photoreduction in a coupled system has rarely been reported. For the first time, we reveal an oxygen-vacancies-mediated photocatalytic strategy in which the electrons and holes are fully utilized for nitrobenzene reduction coupled with benzyl alcohol oxidation. The oxygen vacancies (OVs) generated in situ on the surface of TiO2 greatly extend light absorption into the visible region and promote the photogenerated electron transport for efficient photocatalysis. The experimental and theoretical results together indicate that chemisorption on the TiO2 surface decreases the oxidation potential of benzyl alcohol and causes an upward shift in its HOMO, which facilitates the oxidation reaction of benzyl alcohol to benzaldehyde. The in situ generated surface OVs also act as a bridge to enable the trapping and transferring of the photoinduced electrons to the nitrobenzene. This work provides a new perspective of utilizing the chemisorption between the reactant and catalyst to achieve a defect engineering strategy for synergetic photocatalysis.
关键词： Photocatalysis,Photoreduction,Surface complexation,Oxygen vacancies,Photooxidation
更新于2025-11-14 14:48:53
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Selective reduction of CO2 to CO under visible light by controlling coordination structures of CeOx-S/ZnIn2S4 hybrid catalysts
摘要： Engineering the electronic properties of heterogeneous catalysts is an important strategy to enhance their activity towards CO2 reduction. Herein, we prepared partially sulfurized cerium oxide (CeOx-S) nanoclusters with the size less than 2 nm on the surface of ZnIn2S4 layers. Surface electronic properties of CeOx-S nanoclusters are facilely modulated by cerium coordination to sulfur, inducing the emergence of abundant Ce3+ and oxygen vacancies. For the photoreduction of CO2, CeOx-S/ZnIn2S4 hybrid catalysts exhibited a CO productivity of 1.8 mmol g?1, which was twice as higher as that of ZnIn2S4 catalyst using triethylamine as a sacrificial electron donor. Further mechanistic studies reveal that the photogenerated electrons are trapped by oxygen vacancies on CeOx-S/ZnIn2S4 catalysts and subsequently transfer to CO2, benefiting the activation of CO2. Moreover, the extremely high selectivity of CO is derived from the weak adsorption of CO on the surface of CeOx-S/ZnIn2S4 catalysts.
关键词： CeOx-S Nanoclusters,CO2 photoreduction,Electronic properties,Partial sulfurization,Visible light
更新于2025-09-23 15:22:29
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Bulk Photodriven CO <sub/>2</sub> Conversion through TiO <sub/>2</sub> @Si(HIPE) Monolithic Macrocellular Foams
摘要： Operating photo-induced reactions exclusively on catalyst surfaces while not exploiting the full catalyst volume generates a major footprint penalty for the photocatalytic reactor and leads to an inefficient use of the catalytic material. Photonic investigations clearly show that the solid foams have a strongly multi-diffusive character, with photons being significantly trapped within the sample cores while addressing a photon mean free path lt = 20.1 ± 1.3 μm. This 3D process both greatly limits back-reactions and promotes outstanding selectivity toward methane (around 80%) generation, and even ethane (around 18%) through C-C coupling reaction, with residual carbon monoxide and dihydrogen contents (around 2%). Silica–titania TiO2@Si(HIPE) self-standing macrocellular catalysts lead to optimal efficient thicknesses up to 20 times those of powders, thereby enhancing the way for real 3D-photodriven catalytic processes above the millimeter scale and up to a 6 mm thickness. A rather simple Langmuir–Hinshelwood based kinetic model is proposed which highlights the strong dependence of photocatalytic reaction rates on light scattering and the crucial role on oxidation back-reactions. In addition, a strong correlation between light attenuation coefficient and photon mean free path and median pore aperture diameter is demonstrated, offering thus a tool for photocatalytic behavior prediction.
关键词： heterogeneous catalysis,CO2 photoreduction,sol–gel process,porous materials,integrative chemistry
更新于2025-09-23 15:22:29
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Enhanced Photocatalytic Reduction of Cr(VI) by Combined Magnetic TiO2-Based NFs and Ammonium Oxalate Hole Scavengers
摘要： Heavy metal pollution of wastewater with coexisting organic contaminants has become a serious threat to human survival and development. In particular, hexavalent chromium, which is released into industrial wastewater, is both toxic and carcinogenic. TiO2 photocatalysts have attracted much attention due to their potential photodegradation and photoreduction abilities. Though TiO2 demonstrates high photocatalytic performance, it is a difficult material to recycle after the photocatalytic reaction. Considering the secondary pollution caused by the photocatalysts, in this study we prepared Ag/Fe3O4/TiO2 nanofibers (NFs) that could be magnetically separated using hydrothermal synthesis, which was considered a benign and effective resolution. For the photocatalytic test, the removal of Cr(VI) was carried out by Ag/Fe3O4/TiO2 nanofibers combined with ammonium oxalate (AO). AO acted as a hole scavenger to enhance the electron-hole separation ability, thereby dramatically enhancing the photoreduction efficiency of Cr(VI). The reaction rate constant for Ag/Fe3O4/TiO2 NFs in the binary system reached 0.260 min?1, 6.95 times of that of Ag/Fe3O4/TiO2 NFs in a single system (0.038 min?1). The optimized Ag/Fe3O4/TiO2 NFs exhibited high efficiency and maintained their photoreduction efficiency at 90% with a recyclability of 87% after five cycles. Hence, taking into account the high magnetic separation behavior, Ag/Fe3O4/TiO2 NFs with a high recycling capability are a potential photocatalyst for wastewater treatment.
关键词： magnetic property,reusable,photoreduction,photocatalyst,TiO2
更新于2025-09-23 15:22:29
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1D/2D WO3 nanostructure coupled with nanoparticulate CuO cocatalyst for enhancing solar-driven CO2 photoreduction: The impact of the crystal facet
摘要： Photocatalytic reduction of CO2 into solar fuels is regarded as one of the most promising approaches to address the issues of global warming and the energy crisis. The promotion of spatial charge separation and transfer through crystal facet engineering could be conducive to improved photocatalytic activity. In this study, one-dimensional (1D) WO3 nanowires with a {110} dominant facet (WO3-110) and two-dimensional (2D) WO3 nanosheets with a {001} dominant facet (WO3-001) coupled with CuO nanoparticles are fabricated by a facile method and used for CO2 photoreduction. Its composition and structural characterizations suggest that the WO3-CuO hybrid features good contact between the WO3 and CuO nanostructures. Under light irradiation, the WO3 and WO3-CuO nanostructures are able to photoreduce CO2 into CH4. Notably, the prepared WO3-CuO nanohybrids with different exposed facets show improved CO2 reduction capability compared to pure WO3 and CuO. The heterojunction interface between the WO3 photocatalyst and the CuO cocatalyst through p-n contact can facilitate electron-hole pair separation and accordingly results in enhanced photocatalytic performance. With the assistance of the CuO cocatalyst, the {110} facet WO3-CuO hybrid displays superior photoreduction capability compared to the {001} facet WO3-CuO, which is attributed to the difference in the crystal facets in the heterostructure. The {110} facet WO3 nanowires have a more negative conduction band edge, contributing to the higher reduction capacity of this sample. On the other hand, it is shown that faster charge carrier transfer efficiency would enable more photoinduced electrons to participate in CO2 photoreduction, especially with the involvement of the nanoparticulate CuO cocatalyst. This work provides guidance for designing a hetero-photocatalyst-cocatalyst system through crystal facet engineering.
关键词： WO3-CuO composite,CO2 Photoreduction,1D/2D WO3 nanostructures,heterojunction,crystal facet impact
更新于2025-09-23 15:21:01
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Ni Metal-Organic Frameworks Monolayers for Photoreduction of Diluted CO2: Metal Nodes-Dependent Activity and Selectivity
摘要： Photocatalytic conversion of diluted CO2 into solar fuel is highly appealing yet still in its infancy. Herein, we demonstrate the metal nodes-dependent performance for photoreduction of diluted CO2 by constructing Ni metal-organic frameworks monolayers (Ni MOLs). In diluted CO2 (10%), Ni MOLs exhibits a highest apparent quantum yield of 1.96% with a spectacular CO selectivity of 96.8%, which not only exceeds reported systems in diluted CO2 but also is superior to most catalysts in pure CO2. Whereas its isostructural Co MOLs is almost inactive in diluted CO2, indicating the performance is dependent on the metal nodes. Experimental and theoretical investigations show that strong CO2 binding affinity of Ni MOLs is the crucial factor, which is beneficial to stabilize the Ni-CO2 adducts and facilitates CO2-to-CO conversion. The universality of the superiority of Ni for CO2 photoreduction can be extended to other Ni MOFs, providing an effective general strategy for the design of inorganic-organic complexes for artificial photosynthesis.
关键词： low concertation,MOFs,CO2 photoreduction,monolayers,selectivity
更新于2025-09-23 15:21:01
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Photocatalytic reduction of U(VI) in wastewater by mGO/g-C3N4 nanocomposite under visible LED light irradiation
摘要： Efficient elimination of U(VI) from uranium wastewater is an urgent task for sustainable nuclear energy and environmental protection. In this study, magnetic graphene oxide decorated graphitic carbon nitride (mGO/g-C3N4) nanocomposite was prepared and used for photocatalytic reduction of U(VI) in wastewater under visible LED light irradiation for the first time. The batch experiments indicated that the mGO/g-C3N4 (mGCN) nanocomposite could efficiently reduce U(VI) under visible LED light, and a high U(VI) extraction capacity of 2880.6 mg/g was obtained with an extraction efficiency of 96.02 %. The transmission electron microscopy (TEM) elemental mapping, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analyses demonstrated that the soluble U(VI) was immobilized by transforming it to metastudtite ((UO2)O2?2H2O) by mGCN nanocomposite under visible LED light irradiation. This work indicated that the mGCN is a promising visible light catalyst for treatment of uranium wastewater.
关键词： removal,photoreduction,wastewater,uranium
更新于2025-09-23 15:21:01