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Polyaniline sensitized Pt@TiO2 for visible-light-driven H2 generation
摘要： Polyaniline is a typical conducting polymer with high migration electron rate, good stability, eco-friendly properties, and high absorption coefficients for visible light. In the present study, polyaniline decorated Pt@TiO2 for visible light-driven H2 generation is reported for the first time. The above-mentioned nanocomposite is prepared through a simple oxidative-polymerization and characterized by infrared spectroscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, and ultraviolet-visible diffuse reflectance spectra. Polyaniline modification improves the absorption of the nanocomposite in visible light region via a photosensitization effect similar to dye-sensitization but does not influence the crystal structure and size of Pt@TiO2. The polyaniline modified Pt@TiO2 exhibits a remarkable visible light activity (61.8 μmol h-1 g-1) and good stability for H2 generation (with an average apparent quantum yield of 10.1%) with thioglycolic acid as an electron donor. This work provides new insights into using conducting polymers, including polyaniline, as a sensitizer to modify Pt@TiO2 for visible-light hydrogen generation.
关键词： Polyaniline,TiO2,Hydrogen generation,Photocatalysis
更新于2025-09-19 17:15:36
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Oxygen doped MoS <sub/>2</sub> quantum dots for efficient electrocatalytic hydrogen generation
摘要： In this study, we report an oxygen-doped MoS2 quantum dot (O–MoS2 QD) hybrid electrocatalyst for the hydrogen evolution reaction (HER). The O–MoS2 QDs were prepared with a one-pot microwave method by hydrazine-mediated oxygen-doping. The synthetic method is straightforward, time-saving, and can be applied in large scale preparation. Ultra-small O–MoS2 QDs with the average size of 5.83 nm and 1–4 layers can be uniformly distributed on the surface of reduced graphene oxide (RGO). Benefited from the unique structure and the doping effect of oxygen in the MoS2 QDs and the great number of active sites, the O–MoS2 QD hybrid displayed outstanding electrocatalytic performance toward HER. A low overpotential of 76 mV at 10 mA/cm2 and a Tafel slope of 58 mV/dec were obtained in an acidic solution toward HER. Additionally, the resultant O–MoS2 QD hybrid also exhibited excellent stability and durability toward HER, displaying negligible current density loss after 1000 cycles of cyclic voltammetry. The design and synthesis of the electrocatalyst in this work open up a prospective route to prepare active and stable electrocatalysts toward substituting precious metals for hydrogen generation.
关键词： electrocatalytic hydrogen generation,oxygen-doped MoS2 quantum dots,microwave synthesis,reduced graphene oxide,hydrogen evolution reaction
更新于2025-09-19 17:13:59
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Applications of Laser Ablation - Thin Film Deposition, Nanomaterial Synthesis and Surface Modification || Application of Liquid Laser Ablation: Organic Nanoparticle Formation and Hydrogen Gas Generation
摘要： Laser ablation is induced by a heating process of materials through the absorption of laser light and results in an explosive expansion of materials. For materials located in liquid, in contrast to those in vacuum, laser ablation proceeds under rather mild conditions via a cycle of heating and cooling by mediated solvent; therefore, it is applicable for organic solids to fragment into nanoparticles. Alternatively, for effective light absorbers, the irradiated site becomes the reaction centre of a photochemical reaction even in liquids, resulting in hydrogen gas generation. In this chapter, two topics of laser ablation in the liquid phase are presented: nanoparticle formation of organic materials and hydrogen gas generation from solid carbon in water. Thereby, the extended abilities of liquid laser ablation to transform ordinary materials into functional ones are introduced.
关键词： spectroscopy,carbon-based nanoparticles,hydrogen generation,colloidal solution,nanosecond laser pulses,organic nanoparticles
更新于2025-09-12 10:27:22
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Size dependence of photocatalytic hydrogen generation for CdTe quantum dots
摘要： CdTe quantum dots (QDs) are attractive photosensitizers for photocatalytic proton reduction due to their broad absorbance profile that can extend from the ultraviolet to near-infrared regions, providing access to a larger portion of the solar spectrum than possible with analogous CdSe and CdS QD photosensitizers. Here, the photocatalytic hydrogen (H2) generation from various sizes of dihydrolipoic acid (DHLA)-capped CdTe QDs, ranging from 2.5 to 7.5 nm in diameter, and a molecular Ni-DHLA catalyst in aqueous solutions was evaluated, and an unusual size-dependent photocatalytic activity with CdTe QDs was observed. Under optimized conditions, using 3.4 nm CdTe-DHLA and a 1:20 ratio of QD/Ni-DHLA catalyst, as many as 38 000 turnover numbers (mol H2 per mol QD) were achieved. However, below this critical size, the H2 production efficiency decreased; this behavior is attributed to the rapid oxidation of the QD surface, resulting in detrimental surface trap states. These results are consistent with ultrafast transient absorption spectroscopic measurements, which suggest the presence of extremely fast charge-trapping processes in the oxidized CdTe-DHLA QDs. While fast electron transfer from CdTe-DHLA QDs is observed in the presence of the Ni-DHLA catalyst, the charge trapping processes occur on a competitive time scale, thus lowering the efficiency of the CdTe/Ni-DHLA H2 production system. Understanding rapid charge trapping in CdTe QDs may help suggest potential improvements for the overall CdTe photocatalytic system.
关键词： size dependence,photocatalytic hydrogen generation,Ni-DHLA catalyst,CdTe quantum dots,dihydrolipoic acid
更新于2025-09-12 10:27:22
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5 nm NiCoP nanoparticles coupled with g-C3N4 as high-performance photocatalyst for hydrogen evolution; 负载5 nm磷化钴镍纳米颗粒的石墨相氮化碳高效光催化产氢催化剂;
摘要： Graphitic carbon nitride (g-C3N4) coupled with NiCoP nanoparticles with sizes around 5 nm have been fabricated via a controllable alcohothermal process. NiCoP is an excellent electron conductor and cocatalyst in photocatalytic reactions. The coupling between tiny NiCoP nanoparticles and g-C3N4 through in-situ fabrication strategy could be a promising way to eliminate the light screening effect, hinder the recombination of photo-induced charge carriers, and improve the charge transfer. The NiCoP/g-C3N4 nanohybrids exhibit an excellent photocatalytic activity in the hydrogen generation, with a significantly improved performance compared with original g-C3N4, CoP/g-C3N4 and Ni2P/g-C3N4, respectively. This study paves a new way to design transition metal phosphides-based photocatalysts for hydrogen production.
关键词： nanohybrids,photocatalytic hydrogen generation,carbon nitride,transition metal phosphides
更新于2025-09-12 10:27:22
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Phase-junction design of MOF-derived TiO2 photoanodes sensitized with Quantum Dots for efficient hydrogen generation
摘要： Photoelectrochemical (PEC) water splitting is a promising and environmentally friendly pathway for exploiting renewable energy sources, to address the ever-growing demand for clean energy. Due to its excellent photostability and favorable band alignment, titanium dioxide (TiO2) is the one of the most common metal oxide for water splitting. However, the efficiency in TiO2-based PEC systems is limited by the high recombination of photo-generated electron/hole pairs and large intrinsic band gap (3.2 eV) which limit the absorption of the sunlight. Herein, we explore a simple metal organic framework (MOF)-derived synthesis to obtain a controlled mixed-phase (anatase and rutile) of TiO2 nanoparticles, which retain the MOF crystal morphology. Compared with commercial TiO2 films, the MOF-derived TiO2 film sensitized by core-shell CdSe@CdS QDs, showed an enhanced PEC device stability of +42.1% and PEC performance of +47.6%. The enhanced performance is due to the presence of the mixed rutile/anatase phases, that creates a favorable band energy alignment for the separation of the photogenerated charges. The proposed MOF-derived TiO2 is an efficient strategy to improve the efficiency of the TiO2-QDs heterojunction based PEC system for hydrogen generation.
关键词： Metal organic framework,Mixed-phase TiO2,Photoelectrochemical water splitting,Quantum dots,Hydrogen generation
更新于2025-09-11 14:15:04
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Nanocomposites based on 3D honeycomb-like carbon nitride with Cd0·5Zn0·5S quantum dots for efficient photocatalytic hydrogen evolution
摘要： Honeycomb-like graphitic carbon nitride (HeC3N4) with unique morphology has been studied as a promising polymer photocatalyst. Herein, a novel binary metal sulfide constructed with HeC3N4 (Cd0·5Zn0·5S/HeC3N4) was prepared though the facile in situ precipitation method. The characterization data suggest that Cd0·5Zn0·5S quantum dots (QDs) are well dispersed on the macroporous structure of HeC3N4 (156 m2 g?1), which can provide higher surface area, more catalytic active sites and larger interface contact area with accelerating the migration and separation of charge carriers. By taking advantage of 0D/3D heterojunction structure, the Cd0·5Zn0·5S/HeC3N4 dramatically boosts the photocatalytic H2 evolution rate with the visible-light illumination. The Cd0·5Zn0·5S/HeC3N4-3 yields the highest photocatalytic activity of 5145 mmol h?1 g?1, which is 4.3 times as high as that of pure Cd0·5Zn0.5S. Furthermore, Cd0·5Zn0·5S/HeC3N4 composite presents high stability after four recycles. The enhanced visible-light-driven photocatalytic H2 production is attributed to the construction of n-n type heterojunction as well as the large surface area, which can inhibit the agglomeration of Cd0·5Zn0·5S nanoparticles, and efficiently transfer the photo-excited electron-hole pairs in Cd0·5Zn0.5S. Therefore, this work provides a potential way for designing advanced 0D/3D heterojunction.
关键词： Heterojunction,Honeycomb-like graphitic carbon nitride,Cd0·5Zn0·5S,Photocatalytic hydrogen generation
更新于2025-09-11 14:15:04
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Effect of Linking Pattern of Dibenzothiophene- <i>S</i> , <i>S</i> -dioxide-Containing Conjugated Microporous Polymers on the Photocatalytic Performance
摘要： Conjugated microporous polymers (CMPs) exhibit great potential for photocatalytic hydrogen generation due to their tunable electronic structure. The rational molecular design is a key point for developing an efficient CMP photocatalyst. Herein, we developed two CMPs photocatalysts via the copolymerization from pyrene and dibenzothiophene-S,S-dioxide building blocks. The effect of the linking pattern of the building block of dibenzothiophene-S,S-dioxide on the photocatalytic hydrogen evolution was explored. The polymer of PyDOBT-1 with 3,7-linking pattern shows a superior photocatalytic performance to PyDOBT-2 with 2,8-linking pattern because the 3,7-linking pattern enhances the conjugation chain length and improves the coplanarity of the polymeric backbone, which facilitate the charges migration along the polymer chain. As a result, the bare PyDOBT-1 shows an impressive visible light activity with a hydrogen evolution rate (HER) of 5697 μmol h?1 g?1. Notably, an outstanding HER of 12986 μmol h?1 g?1 was also obtained by the Pt-modified PyDOBT-1 under the full-arc spectrum (λ > 300 nm), which lies toward the upper end compared to that of the reported organic photocatalysts.
关键词： Conjugated microporous polymers,Dibenzothiophene-S,S-dioxide,Photocatalytic hydrogen generation,Linking pattern,Hydrogen evolution rate
更新于2025-09-10 09:29:36
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Enhancement of Photoelectrochemical Hydrogen Evolution of P-Type Silicon Nanowires Array by Loading MoS2
摘要： To improve photoelectrochemical properties of Si nanowires (SiNWs), MoS2/SiNWs is prepared via two-step method. SiNWs is synthesized by metal?catalyzed electroless etching (MCEE) method and MoS2 is subsequently deposited onto SiNWs through the direct thermal decomposition method. MoS2 is introduced as both light absorber and catalyst for hydrogen evolution reaction (HER). Moreover, it forms a heterojunction with SiNWs that contribute to the charge separation. Herein, MoS2/SiNWs attains excellent hydrogen evolution reaction (HER) catalysis with onset potential of 55 mV. A photocurrent density of 25 mA cm?2 at ?1.0 VRHE were achieved under simulated solar illumination, which is about 6 times higher than that of SiNWs, and the carrier concentration is increased by 100?fold. The enhanced photocatalytic activity of MoS2/SiNWs toward HER is attributed to the Schottky junction at the interface, which enhances the photo?generation of electron?hole pairs and suppresses the charge recombination, making them promising earth?abundant alternatives to noble metal?based photocathode for HER.
关键词： MoS2,P?type silicon wires array,Thermal decomposition,Hydrogen generation,Heterojunction
更新于2025-09-10 09:29:36
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Photoelectrochemical water splitting properties of CdS/TiO2 nanofibers-based photoanode
摘要： CdS-sensitized TiO2 nanofibers (CdS/TiO2 NFs) structures were fabricated on the indium tin oxide (ITO) conducting substrate that acts as a working electrode in photoelectrochemical (PEC) cell for the generation of hydrogen by water splitting. TiO2 NFs on ITO conducting substrate were synthesized by electrospinning technique using Titanium tetraisopropoxide as the precursor, followed by a calcination process in air at 500 °C for 2 h. CdS deposition on TiO2 NFs structures was carried out by the dip coating method with different dipping times to optimize the water splitting efficiency. The morphologies and crystalline structures of fabricated samples were characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The PEC properties of the electrodes were measured using a potentiostat instrument in a mixture of 0.25 M Na2S and 0.35 M Na2SO3 aqueous solutions for CdS/TiO2 photoanodes and in 0.5 M Na2SO4 electrolyte for uncoated TiO2 photoanode under the illumination of simulated sunlight (100 mW/cm2 from 150 W xenon lamp). It was found that an optimized TiO2 NFs structure sensitized by CdS layer yields a photoconversion efficiency of 3.2% at 0.0 V (vs. Ag/AgCl). The value of photocurrent density for CdS/TiO2 NFs samples were more than 20 times higher than that of the uncoated TiO2 NFs sample at 0.0 V (vs. Ag/AgCl) under a simulated sunlight irradiation.
关键词： photoelectrochemical water splitting,electrospinning,dip coating,hydrogen generation,CdS/TiO2 nanofibers
更新于2025-09-10 09:29:36