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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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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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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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Visible light assisted photocatalytic reduction of CO2 to ethane using CQDs/Cu2O nanocomposite photocatalyst
摘要： CO2 reduction through photocatalysis is considered a promising way to mitigate the abundance of this greenhouse gas in the earth’s atmosphere. In this work, blue-fluorescent carbon quantum dots (CQDs) were synthesized via a facile top-down hydrothermal method using biochar as the carbon source. The as-synthesized CQDs were incorporated together with commercial copper (I) oxide (Cu2O) nanoparticles to form CQDs/Cu2O nanocomposite. The CQDs, Cu2O and CQDs/Cu2O nanocomposite were then applied for gas phase photocatalytic reduction of CO2. The experiments were performed under visible light irradiation in a self-designated photoreactor which was connected to an online Gas Chromatography (GC). High resolution transmission electron microscopy (HRTEM) confirmed the uniform deposition of CQDs with size ranging from 2.5 to 6.0 nm on the surface of Cu2O nanoparticles. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy further revealed the presence of CQDs on the surface of Cu2O. The CQDs/Cu2O nanocomposite photocatalyst showed a considerable improvement in the CO2 photoreduction with an enhancement of 54% compared to the pure Cu2O. In addition, the band alignment of CQDs/Cu2O, charge carriers transfer and separation as well as possible reaction pathways for CO2 photoreduction was proposed. Finally, the photostability test revealed the CQDs/Cu2O nanocomposite was able to retain its photostability of up to ~90% under five cycles of photoreaction.
关键词： copper (I) oxide,carbon quantum dots,CO2 photoreduction,photocatalyst
更新于2025-09-23 15:21:01
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Plasmonic Electronsa??Driven Solara??toa??Hydrocarbon Conversion over Au NR@ZnO Corea??Shell Nanostructures
摘要： This work demonstrates the long-range redox reactivity of gold plasmon-generated hot electrons for solar-driven CO2 conversion. A series of Au NR@ZnO core-shell photocatalysts with a tunable shell thickness are rationally designed to achieve the solar-to-CH4 conversion, where the hot plasmonic electrons-induced photoreduction takes place on the polar oxide moiety. The shell thickness-independent activity implies that the core, gold nanorods, plays a dominant role in the CH4 generation. The ZnO metal oxide semiconductor shell is beneficial to prolong the lifetime of hot electrons, thereby enhancing the photocatalytic efficiency. However, the thickness of ZnO shell is not relevant to the production rate. Both of these two parts are co-excitated by solar light and synergetic enhance the photocatalytic activity.
关键词： gold nanorod,core-shell nanostructure,ZnO,photocatalysis,CO2 photoreduction,plasmon resonance
更新于2025-09-23 15:19:57
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Phenyl-grafted carbon nitride semiconductor for photocatalytic CO2-reduction and rapid degradation of organic dyes
摘要： Molecular engineering of graphitic carbon nitride (g-C3N4) is achieved by the copolymerization of π-conjugated phenyl urea, melamine, and urea. Integration of aromatic phenyl rings into the heptazine network of g-C3N4 alters its structural, optical and electronic properties. The fusion of polymeric g-C3N4 core with aromatic phenyl groups induces band gap tuning, greatly improves the separation and lifetime of charge-carriers. As a result, CO2 photoreduction experiments conducted by using phenyl grafted g-C3N4 afford methane and formic acid in high yields. Furthermore, a selective model organic pollutant rhodamine B dye is rapidly decomposed under visible light irradiation. This work suggests that pyrolysis of a suitable aromatic π-deficient molecular dopant such as phenyl urea can drastically alter the photo-response of carbon nitride photocatalyst and may enhance its photocatalytic activity. Hence, the present work is expected to be of significant value in sustainable energy production and environmental remediation.
关键词： CO2 photoreduction,photocatalysis,Carbon nitride,Phenyl grafted g-C3N4,dye degradation
更新于2025-09-19 17:15:36
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New Understanding of Crystal Control and Facet Selectivity of Titanium Dioxide Ruling Photocatalytic Performance
摘要： Engineering crystals of titanium dioxide (TiO2) to expose with the most reactive facet has been proved to significantly improve the photocatalytic performance. While most of TiO2 with facets reported in the past were in a particle form, herein we directly grow TiO2 with arbitrarily tunable facets onto the transparent conductive substrate. This could reduce interparticle boundaries, and thus suppress charge recombination and facilitate more efficient charge transport compared to particle-assembled films. Combined systematic experimental and theoretical (Density Function Theory, DFT) studies reveal that fluoride ions (F-) and protons (H+) could play a synergistic role in controlling TiO2 crystals in the way that F- ions change the crystal phase of TiO2 to anatase with low-indexed facets, while H+ ions increase of {001}/{101} ratio. Moreover, the reductive and oxidative sites of facets are clearly elucidated by a selective photodeposition of noble metal and metal oxide. Different photocatalytic tests manifested that {001} facet, which is conventionally believed as the highest reactive facet, does not always show highest performance. On the other hand, the facets reactivity appeared to depend on the types of reactions (reduction or oxidation) and the co-existing synergy of facets. These findings would clarify the ambiguous understanding about the true factors controlling facets, the true order of reactivity of each facet that has still been controversial, and pave a way to improve both efficiency and selectivity of TiO2 in a wide variety of photocatalytic applications in the future.
关键词： Facet Control,CO2 Photoreduction,TiO2,Crystal Growth,PEC Water Splitting
更新于2025-09-19 17:15:36