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- 摘要
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- 实验方案
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Modification of reduced graphene oxide layers by electron-withdrawing/donating units on molecular dopants: Facile metal-free counter electrode electrocatalysts for dye-sensitized solar cells
摘要： Small molecules of aniline (AN) and nitrobenzene (NB) doped on reduced graphene oxide nanosheets (rGO) represent the attractive Pt-free and earth abundant counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). Scanning electron microscope and transmission electron microscope confirm a very thin layer structure with wrinkled and folded nanosheets. The binding between AN or NB and rGO is confirmed by Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). In this work, two different redox electrolytes are investigated: I?/I3? and [Co(bpy)3]3+/2+. Compared to rGO electrode-based DSSCs, the AN-rGO (1:10) and NB-rGO (1:10) electrode-based DSSCs applying I?/I3? and [Co(bpy)3]3+/2+ electrolytes show 40–50% and 30–35% increase in power conversion efficiency, respectively. Furthermore, both AN-rGO (1:10) and NB-rGO (1:10) perform stably upon electrochemical continuous test. Such excellent photoelectric performance correlates with the induced charge transfer between reduced graphene oxide and the molecules which effectively promotes the reduction and regeneration of I?/I3? and [Co(bpy)3]3+/2+ ions.
关键词： Electrocatalyst,Dye-sensitized solar cell,Molecular dopant,Reduced graphene oxide,Counter electrode
更新于2025-09-23 15:19:57
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Highly efficient bio-based porous carbon hybridized with tungsten carbide as counter electrode for dye-sensitized solar cell
摘要： Bio-based porous carbon (CMA and CTA) are successfully prepared from waste carton via microwave-assisted activation (MA) and two-step chemical activation (TA) methods, respectively. The as-prepared CTA sample exhibits higher specific surface area (824.16 m2 g?1) and larger total pore volume (0.71 cm3 g?1), as compared with those of the CMA sample (655.36 m2 g?1 and 0.62 cm3 g?1, correspondingly). The higher specific surface area could provide more catalytic sites; thus, the dye-sensitized solar cell (DSSC) assembled with a CTA counter electrode (CE) deliver a power conversion efficiency (PCE) of 6.76%, surpass the CMA-based DSSC (6.19%). Further, tungsten carbide (WC) are introduced into CTA and CMA to form hybrid catalysts (WC/CTA and WC/CMA, respectively) in order to improve their catalytic activities. Benefitting from the synergistic effect of bio-based porous carbon and WC, the DSSCs with WC/CTA and WC/CMA CEs exhibit superior PCE values of 7.32% and 6.85%, respectively, close to Pt (7.51%). This work provides an effective strategy for synthesizing low-cost and high-performance hybrid catalysts from bio-based carbon to achieve resource utilization of biomass waste in new energy fields.
关键词： Electrocatalyst,Counter electrode,Bio-based carbon,Tungsten carbide,Dye-sensitized solar cell
更新于2025-09-23 15:19:57
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Hybridizing NiCo2O4 and amorphous NixCoy layered double hydroxides with remarkably improved activity towards the efficient overall water splitting
摘要： Overall water splitting is an attractive technology to produce clean hydrogen and oxygen. In this study, we constructed amorphous NixCoy layered double hydroxide (LDH) hybridized with three-dimensional NiCo2O4 to fabricate core-shell nanowire array on Ni foam (NiCo2O4@NixCoy LDH/NF) as highly efficient electrocatalyst for overall water electrolysis. By tuning the Ni/Co molar ratio in NixCoy LDH, extremely low overpotentials of 193 mV for oxygen evolution reaction (OER) and 115 mV for hydrogen evolution reaction (HER) at a current density of 10 mA cm?2 can be achieved for the NiCo2O4@Ni0.796Co LDH/NF. Detailed investigations verify that the hybrid structure can increase intrinsic activity of the NiCo2O4@Ni0.796Co LDH/NF and enhance the charge-transfer rate. Moreover, a strong electronic interaction between the heterogeneous elements Ni and Co at the interface of the NiCo2O4 and NixCoy LDH might ultimately influence the catalytic performance.
关键词： bifunctional electrocatalyst,nanowire arrays,amorphous material,layered double hydroxide,water splitting
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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Size-controlled MoS<sub>2 </sub>nanosheet through ball milling exfoliation: parameter optimization, structural characterization and electrocatalytic application
摘要： Unique properties and potential applications of 2D materials draw much attention for mass production of thin-layer 2D materials. Ball milling exfoliation of 2D materials has been rarely used, in spite of a promising dry phase production method, because of the superficial information in the mechanism and the effect of the operating parameters on the yield, size and thickness. Here, we investigate systematically the ball milling operating parameters in the exfoliation of bulk MoS2 in the presence of sodium cholate (SC) as an exfoliant. The yield and dimensions of the exfoliated MoS2 nanosheet were monitored by changing the parameters such as the weight ratio of bulk MoS2 and SC (SC/MoS2), the filling ratio in the volume of milling ball and container (!), milling ball size (dB), milling revolution speed (nR), and initial mass of bulk MoS2 (mMoS2). The yield of exfoliation is found to be 95% at the optimum ball milling conditions (SC/MoS2 = 0.75, ! = 50%, mMoS2 = 0.20 g). In addition, yield and size of the exfoliated MoS2 were controlled by the conditions of the ball milling. As for the evaluation of size and thickness of the ball-milled MoS2 powder with less than 30% difference from those determined by the well-known absorption method. Finally, the size and thickness of the MoS2 nanosheets prepared by ball milling exfoliation were correlated with their electrocatalytic and photoelectrocatalytic activities.
关键词： electrocatalyst,sodium cholate,nanosheet,exfoliation,Ball milling,molybdenum disulfide,XRD
更新于2025-09-19 17:13:59
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PVP assisted hydrothermal synthesis of CuCoO2 nanoplates with enhanced oxygen evolution reaction performance
摘要： Tuning size and morphology and exploiting new catalytic materials are several important strategies commonly used to develop highly efficient oxygen evolution reaction (OER) electrocatalysts. In this work, we report the synthesis of CuCoO2 (CCO) nanoplates through a facile one-step PVP assisted hydrothermal process. The influence of hydrothermal reaction parameters, including the precursor composition, reaction temperature and duration, on the morphology, size and crystal phase of CCO crystals has been investigated in detail. In addition, X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) have been used to comprehensively characterize CCO’s crystal structure, morphology, composition and chemical states of elements. Furthermore, the electrocatalytic performance of CCO nanoplates towards the OER is studied and compared to that of CCO micrometer-sized crystals. The CCO nanoplates only require a low overpotential of 390 mV to attain an anodic current density 10 mA cm-2 in alkaline solution, and show comparatively fast OER kinetics with a Tafel slope of 70 mV dec-1 and reasonably good long-term catalytic stability, substantially outperforming CCO micro-crystals, which highlights the importance of size and morphology of CCO for use in OER electrocatalysis.
关键词： Water splitting,Oxygen evolution reaction,CuCoO2,Delafossite,Electrocatalyst
更新于2025-09-10 09:29:36
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Fabricating Cu, Cu<sub>2</sub>O and Hybrid Cu-Cu<sub>2</sub>O nanoparticles in carbon matrix and exploring catalytic activity of oxygen and hydrogen evolution and green A<sup>3</sup>-coupling reaction
摘要： Hybrid Cu-Cu2O as well as Cu and Cu2O@C nanoparticles (NPs) encapsulated by carbon matrix have been synthesized and bifunctional electrocatalytic activity (OER and HER) and A3 coupling (three components reaction) were explored. Powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), and high resolution transmission electron microscopy (HR-TEM) studies were performed to analyse structure, chemical state, and size of the nanocatalysts. Hybrid Cu-Cu2O@C materials exhibited stronger electrocatalytic activity compared to pure phases whereas pure Cu and Cu2O@C NPs displayed better catalytic activity for A3 coupling reaction. Oxygen and hydrogen evolution reaction (OER and HER) showed enhanced current response (57.8 mA/cm2 and -172 mA/cm2) for hybrid NPs with higher Cu2O ratio. Thus, the present work investigated the role of Cu and Cu2O ratio for fabricating earth abundant cost effective nanocatalysts for OER, HER, and organic chemical transformation.
关键词： Water splitting,A3 coupling,Oxygen evolution reaction,Hydrogen evolution reaction,Cu-Cu2O nanoparticles,Electrocatalyst
更新于2025-09-10 09:29:36
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Influence of solvent in solvothermal synthesis of Cu3SnS4: Morphology and band gap dependant electrocatalytic hydrogen evolution reaction and photocatalytic dye degradation
摘要： Cu3SnS4 (CTS) with various morphologies have been synthesized via solvothermal method. The influence of different solvents such as deionized water (CTS-DI), N,N-dimethylformamide (CTS-DMF) and poly ethylene glycol (CTS-PEG) has been investigated. XRD patterns of all the prepared samples exhibit tetragonal structure with preferential orientation along (1 1 2) direction. It is found that the solvents play a key role to tune the morphology and band gap. The morphology varied as irregular sheet like structure, mesoporous structure and feather like structure for CTS-DI, CTS-DMF and CTS-PEG, respectively. The band gap was found to be 1.33, 1.65 and 1.19 eV for CTS-DI, CTS-DMF and CTS-PEG, respectively. Electrocatalytic hydrogen evolution reaction and photocatalytic dye degradation of MB were tested using the prepared CTS samples. As an electrocatalyst or photocatalyst, it is found that CTS-DMF with mesoporous structure shows an enhanced catalytic activity with lower overpotential, a smaller Tafel slope (88 mV/dec), high stability in acidic medium and an enhanced photocatalytic activity. A more realistic mechanism for the photocatalytic activity of CTS-DMF is proposed.
关键词： Solvothermal,Cu3SnS4,Electrocatalyst,Photocatalyst
更新于2025-09-09 09:28:46
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Aluminum and Nitrogen Codoped Graphene: Highly Active and Durable Electrocatalyst for Oxygen Reduction Reaction
摘要： The development of highly active and exceedingly durable electrocatalyst at low cost for oxygen reduction reaction (ORR) is extremely desirable, but remains to be a grand challenge. Over the past decade, the transitional-metal (e.g., Fe, Co, Ni) and N codoped graphene materials have attracted most attention as the state-of-the-art non-precious-metal-based effective electrocatalyst for ORR, but still entail unsatisfactory issues such as moderate activity and life. Herein, the main-group-metal Al and N codoped graphene (ANG) is successfully fabricated via thermal annealing treatment of N-doped graphene with aluminum tri-(8-hydroxyquinoline). As a highly effective electrocatalyst for ORR, the as-prepared ANG exhibits not only high electrocatalytic activity that even outperforms the commercial Pt/C, but also good durability in both three-electrode cell and Zn-air battery. Theory calculations show that the inhomogeneous charge density distribution and the interaction between Al and N are mainly responsible for the marked enhancement of ORR activity. The designed ANG electrocatalysts will provide a perspective application in energy storage and promote further exploration of main-group-element-based inexpensive, active and durable electrocatalysts.
关键词： N-doped graphene,noble-metal free,Al-doped graphene,oxygen reduction reaction,electrocatalyst
更新于2025-09-09 09:28:46
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Evaluation of electroless Pt deposition and electron beam Pt evaporation on p-GaAs as a photocathode for hydrogen evolution
摘要： This study examines the changes in the photoelectrochemical (PEC) properties with Pt morphology after wet (electroless Pt deposition) and dry (e-beam Pt evaporation) deposition of Pt on p-GaAs. The Pt morphology and composition of the p-GaAs surface differed depending on the Pt deposition method, which in turn affected the optical and PEC properties of Pt on the GaAs electrode. Thus, the findings of this study can help in gaining a clearer understanding of the manner in which these changes affect the operation of a GaAs PEC water-splitting electrode.
关键词： Electrocatalyst,Electron beam evaporation,Gallium arsenide,Water splitting,Electroless deposition,Platinum
更新于2025-09-04 15:30:14