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Solid-phase hot-pressing of POMs-ZIFs precursor and derived phosphide for overall water splitting
摘要： A facile solid-phase hot-pressing method was applied to prepare bimetallic phosphides on carbon cloth without binder as efficient electrocatalysts for water splitting. High-performance electrocatalyst with high performance for both hydrogen and oxygen evolution reaction is attracting considerable attention in recent years. However, most electrocatalysts are powders and require to deposit on conductive substrates with binders, leading to complicated steps and hindering the improvement of long-term stability. This work exhibits a solid-phase hot-pressing method to prepare polyoxometalates based zeolitic imidazolate frameworks (POMs-ZIFs) precursor on carbon cloth (CC) rapidly and mildly. After phosphidation treatment, nitrogen-doped graphitic carbon layers coated phosphide on CC (CoP/MoP@NC/CC) is synthesized. CoP/MoP@NC/CC has excellent electrocatalytic performance for water splitting due to the synergistic effect of CoP, MoP and as-formed oxide/hydroxide layers. It shows the low overpotentials of 94 mV for HER and 270 mV for OER at the current density of 10 mA cm-2 in alkaline medium, which is superior to most of the reported phosphide-based electrocatalysts. Notably, the ultra-high current density of 1000 mA cm-2 can be reached at the overpotentials of only 475 mV for HER and 657 mV for OER. As both cathode and anode for overall water splitting, CoP/MoP@NC can achieve the current density of 50 mA cm-2 at the cell voltage of 1.71 V. The solid-phase hot-pressing method ensures the tight and uniform growth of the fast nucleating and stable materials on substrate and applies for more electrochemical reactions.
关键词： phosphide,hot-pressing,HER,OER,metal-organic framework
更新于2025-09-23 15:23:52
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One Dimensional CdS Nanotube vs CdS Bulk Structure for Photocatalytic Water Splitting: Role of Dimensionality
摘要： Using the state-of-the-art density functional theoretical calculations, we have modelled a facetted CdS nanotube (NT) catalyst for photocatalytic water splitting. The overall photocatalytic activity of the CdS photocatalyst has been predicted based on the electronic structures, band edge alignment, and overpotential study. For comparisons, we have also investigated the water spilitting process over the CdS bulk structure. The band edge alignment along with oxygen evolution reaction/hydrogen evolution reaction (OER/HER) mechanism studies help us to find out the effective overpotential for the overall water splitting on these surfaces. Our study shows that CdS NT has highly stabilized valence band edge compared to that in the CdS bulk due to strong p-d mixing. Such highly stabilized valence band edge is important for the hole-transfer process and reduces the risk of electron-hole recombination. Such nanotube requires less overpotential for water oxidation reaction than the periodic CdS. All these suggest that the efficiency of water oxidation/reduction process further improves in CdS as we reduce its dimensionality. More importantly, we report here that there are two factors, which makes CdS nanotube as a better photocatalyst material compared to its bulk counterpart. Furthermore, the stabilized valence band edge is good for their photostability too as bulk CdS suffers from photostability.
关键词： photocatalysis,HER,CdS nanotube,OER,electron-hole recombination
更新于2025-09-23 15:21:01
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SiO2-stabilized Bi nanoparticles: a high active and stable visible light photocatalyst
摘要： A SiO2-coated Bi nanoparticle structure in 40?60 nm with high activity and stability was designed by a liquid phase chemical reduction method. The effect of SiO2 layer on high active Bi nanoparticles was studied by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and thermo-gravimetric and differential thermal analysis characterizations. The SiO2 layer effectively enhanced the stability of Bi core without having negative effect on its activity. The as-prepared Bi@SiO2 nanoparticles showed high activity and recycling stability both in photocatalytic degradation of pollutant (rhodamine B and bisphenol A, respectively) and hydrogen exhalation reaction (HER). The photocatalytic degradation mechanism of Bi@SiO2 nanoparticles under visible light irradiation was discussed. The porous structure of SiO2 layer performed transport channel for electrons and active species, and enhanced the plasmonic photocatalytic effect of Bi.
关键词： HER.,stabilization,photocatalytic activity,Bi@SiO2 nanoparticles
更新于2025-09-19 17:15:36
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High-performance hydrogen evolution of MoSe2-Mo2C seamless heterojunction enabled by efficient charge transfer
摘要： A novel heterojunction consisted of Mo2C and MoSe2 is synthesized through CVD as high-performance electrocatalyst for HER in both acidic and basic media. The enhanced conductivity and the large surface area of as-prepared Mo2C/MoSe2 contribute to the efficient HER. Further DFT calculations can prove that in the interface region of Mo2C and MoSe2, there are MIGS which could benefit the fast charge transfer, boosting the hydrogen evolution.
关键词： DFT calculations,HER,Mo2C,heterojunction,CVD,MoSe2,electrocatalyst,MIGS
更新于2025-09-19 17:13:59
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Exploring Synergistic effect of Ni <sub/>x</sub> Sn <sub/>2x</sub> S <sub/>4x</sub> Thiospinel with MWCNTs with Enhanced Performance in Dye Sensitized Solar cells, Hydrogen Evolution Reaction and as Supercapacitor
摘要： Trifunctional nickel tin sulfide (NixSn2xS4x) thiospinel like structure composited with multiwall carbon nanotubes (MWCNTs) (M–NixSn2xS4x) was synthesized by a facial method. The unit cell arrangement of prepared composite has been studied by Density Functional Theory (DFT) and the theoretical interpretation satisfactorily inferred the presence of synergistic effect between thiospinel and MWCNTs. High metallic conductivity and superior electrocatalytic activities of M–NixSn2xS4x composite plays a prominent diverse roles as counter electrode for dye sensitized solar cells (DSSCs) with 4.67 % efficiency when compared to Pt (5.23 %) at fluorine doped indium tin oxide (FTO), efficient catalyst like Pt for hydrogen evolution reaction (HER) with good cyclic stability and low over potential of ?41 mV at the cathode current density of 10 mA cm2 and Tafel slope of 43 mV/dec at graphite sheet electrode and as impressive capacitance material at graphite sheet electrode alternate to an expensive current collectors like Ni foam with a specific capacitance value of 1,200 Fg?1 at current density of 1 Ag?1 and long life span of 92.6 % retained up to 15,000 cycles.
关键词： HER,Thiospinel,hybrid supercapacitors,cyclic stability,low overvoltage,DSSCs
更新于2025-09-19 17:13:59
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Facile, rapid, and well‐controlled preparation of Pt nanoparticles decorated on single surface of MoS2 nanosheets and application in HER
摘要： Recently, asymmetrically functionalized two-dimensional (2D) nanomaterials have attracted fevered interest as excellent candidates for building blocks of multifunctional and multidimensional systems due to the structural symmetry-breaking. However, their preparation process typically involves high vacuum environment or specific equipment, and the obtained samples have poor stability and low yield. In this study, a facile approach has been developed to achieve the asymmetric deposition of platinum nanoparticles (NPs) onto single side of the molybdenum disulfide (MoS2) nanosheets by pyrogenic decomposition and in-situ functionalization. By tuning the platinum precursor to MoS2 ratio, the size distribution and morphology of the Pt NPs can be well controlled. The asymmetrical decoration of Pt NPs on MoS2 nanosheets (Pt-MoS2) may result from the superior interactions between Pt NPs and MoS2 basal surface, which are stronger than the van der Waals force between adjacent MoS2 layers. Hydrogen evolution reaction (HER) results show that higher Pt loading yields better HER performance with low overpotential of 120 mV and superior Tafel slope of 28 mV·dec-1. Significantly, the current synthetic method can be used in the asymmetrical functionalization of other 2D nanosheets as well, and could greatly advance the facile preparation and practical applications of these asymmetric nanostructures.
关键词： HER,nanosheet,molybdenum disulfide,nanoparticles,asymmetric structure
更新于2025-09-12 10:27:22
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A New Class of Zn <sub/>1</sub><i> <sub/>-x</sub></i> Fe <i> <sub/>x</sub></i> -Oxyselenide and Zn <sub/>1-</sub><i> <sub/>x</sub></i> Fe <i> <sub/>x</sub></i> -LDH Nanostructured Material with Remarkable Bifunctional Oxygen and Hydrogen Evolution Electrocatalytic Activities for Overall Water Splitting
摘要： The scalable and cost-effective H2 fuel production via electrolysis demands an efficient earth-abundant oxygen and hydrogen evolution reaction (OER, and HER, respectively) catalysts. In this work, for the first time, the synthesis of a sheet-like Zn1-xFex–oxyselenide and Zn1-xFex–LDH on Ni-foam is reported. The hydrothermally synthesized Zn1-xFex–LDH/Ni-foam is successfully converted into Zn1-xFex–oxyselenide/Ni-foam through an ethylene glycol-assisted solvothermal method. The anionic regulation of electrocatalysts modulates the electronic properties, and thereby augments the electrocatalytic activities. The as-prepared Zn1-xFex–LDH/Ni-foam shows very low OER and HER overpotentials of 263 mV at a current density of 20 mA cm?2 and 221 mV at 10 mA cm?2, respectively. Interestingly, this OER overpotential is decreased to 256 mV after selenization and the HER overpotential of Zn1-xFex–oxyselenide/Ni-foam is decreased from 238 to 202 mV at 10 mA cm?2 after a stability test. Thus, the Zn1-xFex–oxyselenide/Ni–foam shows superior bifunctional catalytic activities and excellent durability at a very high current density of 50 mA cm?2. More importantly, when the Zn1-xFex–oxyselenide/Ni-foam is used as the anode and cathode in an electrolyzer for overall water splitting, Zn1-xFex–oxyselenide/Ni-foam(+)∥Zn1-xFex–oxyselenide/Ni-foam(-) shows an appealing potential of 1.62 V at 10 mA cm?2. The anionic doping/substitution methodology is new and serves as an effective strategy to develop highly efficient bifunctional electrocatalysts.
关键词： Zn1-xFex–oxyselenide,Zn1-xFex–LDH,overall water splitting,HER,OER
更新于2025-09-10 09:29:36
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Plasmon-Enhanced Electrocatalytic Properties of Rationally Designed Hybrid Nanostructures at a Catalytic Interface
摘要： In recent years, a promising role of plasmonic metal nanoparticles (NPs) has been demonstrated toward an improvement of the catalytic efficiency of well-designed hybrid electrocatalysts. In particular, the coupling of plasmonic functionality with the metal-based core–shell architectures in plasmon-enhanced electrocatalysis provides a sustainable route to improve the catalytic performances of the catalysts. Herein, the rationally designed AuNPs wrapped with reduced graphene oxide (rGO) spacer along with PdNPs (AuNP@rGO@Pd) as the final composite are reported. The rGO is proposed to promote the reduction of PdO, greatly enhance the conductivity, and catalytic activity of these nanohybrid structures. The plasmon-enhanced electrocatalytic performance of optimized AuNP@rGO(1)@Pd exhibits an ≈1.9- and 1.1-fold enhanced activity for the hydrogen evolution reaction and oxygen evolution reaction, respectively. The final composite also exhibits a superior stability up to 10 000 s compared with the commercial Pd/C. The mechanism of the enhanced catalytic performance is monitored through in situ X-ray absorption spectroscopy by observing the generated electron density under light irradiation. The results demonstrate that the energetic charge carriers are concentrated in the incorporated PdNPs, allowing higher catalytic performances for the overall water-splitting reaction. The conclusions herein drawn are expected to shed light on upcoming plasmon-induced electrocatalytic studies with analogous hybrid nanoarchitectures.
关键词： plasmonic nanoparticles,heterogeneous catalysis,photo-electrocatalysis,oxygen evolution reaction (OER),hydrogen evolution reaction (HER)
更新于2025-09-09 09:28:46
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CTAB-assisted synthesis of dissilient hollow spherical MoS2 for efficient hydrogen evolution
摘要： Dissilient hollow spherical MoS2 was prepared by one-step hydrothermal method using cetyltrimethyl ammonium bromide (CTAB) as a surfactant. The structure and morphology of the prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The addition of CTAB plays an important role in controlling the morphology of MoS2. As the amount of CTAB was increased, the morphology of MoS2 changed from flake to hollow sphere and finally broked up. Compared with MoS2 without CTAB and closed hollow spherical MoS2, the dissilient hollow spherical MoS2 showed better electrochemical performance in the hydrogen evolution reaction (HER) and good stability after 1000 cycles. We attribute this improvement to large specific surface area and many catalytic active sites of the dissilient hollow spheres. In general, the optimized catalyst exhibited an onset overpotential of 159 mV, a low Tafel slope of 65 mV dec-1, and relatively good stability.
关键词： HER,Dissilient,MoS2,CTAB,Hollow sphere
更新于2025-09-09 09:28:46
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Pyrite-Type CoS2 Nanoparticles Supported on Nitrogen-Doped Graphene for Enhanced Water Splitting
摘要： It is extremely meaningful to develop cheap, highly efficient, and stable bifunctional electrocatalysts for both hydrogen and oxygen evolution reactions (HER and OER) to promote large-scale application of water splitting technology. Herein, we reported the preparation of CoS2 nanoparticles supported on nitrogen-doped graphene (CoS2@N-GN) by one-step hydrothermal method and the enhanced electrochemical efficacy for catalyzing hydrogen and oxygen in water electrolysis. The CoS2@N-GN composites are composed of nitrogen-doped graphene and CoS2 nanocrystals with the average size of 73.5 nm. Benefitting from the improved electronic transfer and synergistic effect, the as-prepared CoS2@N-GN exhibits remarkable OER and HER performance in 1.0 M KOH, with overpotentials of 243 mV for OER and 204 mV for HER at 10 mA cm?2, and the corresponding Tafel slopes of 51.8 and 108 mV dec?1, respectively. Otherwise, the CoS2@N-GN hybrid also presents superior long-term catalytic durability. Moreover, an alkaline water splitting device assembled by CoS2@N-GN as both anode and cathode can achieve a low cell voltage of 1.53 V at 60 ?C with a high faraday efficiency of 100% for overall water splitting. The tremendously enhanced electrochemical behaviors arise from favorable factors including small sized, homogenously dispersed novel CoS2 nanocrystals and coupling interaction with the underlying conductive nitrogen-doped graphene, which would provide insight into the rational design of transition metal chalcogenides for highly efficient and durable hydrogen and oxygen-involved electrocatalysis.
关键词： water splitting,HER/OER,graphene,nanoparticle,composite,cobalt sulfide
更新于2025-09-09 09:28:46