Pt-based Dye-sensitized Solar Cells Research Articles

Enhanced efficiency and stability of dye-sensitized solar cells utilizing FeCo2S4 nanowires as Pt-free counter electrodes

Replacing traditional Pt-based counter electrodes with low-cost and highly stable materials is crucial for the development of commercially viable dye-sensitized solar cells (DSSCs). In this study, we synthesized a ternary Pt-free FeCo2S4 nanowire (NW)-based sulfide electrocatalyst by a three-step solvothermal method. This material was then used as a counter electrode in DSSCs to facilitate the reduction of triiodide species. The formation of FeCo2S4 NW was confirmed by various characterization techniques such as X-ray diffraction, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Scanning electron microscopy analysis revealed the structure of the nanowires. Electrochemical studies, which included cyclic voltammetry, electrochemical impedance spectroscopy and Tafel polarization methods, revealed the excellent stability, superior electrocatalytic activity and remarkable kinetics of FeCo2S4 NW in the reduction of triiodide to iodide. Photovoltaic measurements of the fabricated DSSCs yielded a power conversion efficiency (PCE) of 7.88 % for the FeCo2S4-based devices, outperforming the control device made of Pt (PCE=7.45 %). This improvement was primarily due to the increase in short-circuit current density (JSC), thanks to the lower charge transfer resistance (RCT) of FeCo2S4 NW (JSC=15.23 mA/cm2; RCT=5.54 Ω cm2) compared to Pt (JSC=14.12 mA/cm2; RCT=7.07 Ω cm2). In addition, the FeCo2S4 NW-based solar cells exhibited excellent stability and maintained their high PCE value even after 10 days of aging under ambient conditions, while Pt-based DSSCs showed a 3 % decrease from their initial PCE value. This FeCo2S4 NW counter electrode proves to be an excellent alternative to Pt, and the presented results provide valuable insights for the development of cost-effective and highly stable DSSCs.

Dual Application of Waste Grape Skin for Photosensitizers and Counter Electrodes of Dye-Sensitized Solar Cells.

Dye-sensitized solar cells (DSSCs), a powerful system to convert solar energy into electrical energy, suffer from the high cost of the Pt counter electrode and photosensitizer. In this study, the dual application of waste grape skin is realized by employing the grape skin and its extract as the carbon source of the carbon-based counter electrode and photosensitizer, respectively. The ultraviolet–visible absorption and Fourier transform infrared spectroscopy verify the strong binding between the dye molecules (anthocyanins) in the extract and the TiO2 nanostructure on the photoanode, contributing to a high open-circuit voltage (VOC) value of 0.48 V for the assembled DSSC device. Moreover, the waste grape skin was subjected to pyrolysis and KOH activation and the resultant KOH-activated grape skin-derived carbon (KA-GSDC) possesses a large surface area (620.79 m2 g−1) and hierarchical porous structure, leading to a high short circuit current density (JSC) value of 1.52 mA cm−2. Additionally, the electrochemical impedance spectroscopy reveals the efficient electron transfer between the electrocatalyst and the redox couples and the slow recombination of electrolytic cations and the photo-induced electrons in the conduction band of TiO2. These merits endow the DSSC with a high photovoltaic efficiency of 0.48%, which is 33% higher than that of a common Pt-based DSSC (0.36%). The efficiency is also competitive, compared with some congeneric DSSCs based on other natural dyes and Pt counter electrode. The result confirms the feasibility of achieving the high-value application of waste grape skin in DSSCs.

Design and Fabrication of High Performance Photoanode of Fe2(MoO4)3/RGO Hybrid Composites for Triiodide Reduction in Dye-Sensitized Solar Cells

Here in, synthesis of Fe2(MoO4)3/reduced graphene oxide (RGO) nanocomposite was prepared by simple hydrothermal approach and used as high efficient dye sensitized solar cells (DSSCs). The decoration of RGO into the Fe2(MoO4)3 was proved by various physic-chemical studies such as XRD, SEM, TEM, Raman, UV, PL and BET analysis. The individual spherical shaped nanoparticles of Fe2(MoO4)3 with sizes in the range of 25–35 nm was uniformly decorated on the surface of RGO nanosheets. Due to the synergic effect between the Fe2(MoO4)3 and RGO the light absorption property is significantly improved as well the high surface area (112.5 m2/g) and pore size (38.7 nm) was achieved than compared with bare Fe2(MoO4)3 (88.5 m2/g and 17.8 nm). The Fe2(MoO4)3/RGO hybrid photoanode establish to display an outstanding catalytic activity toward the reduction of triiodide to iodide in a dye-sensitized solar cell (DSSC) and can provide a solar cell efficiency of 9.6 ± 0.001%, which is superior to a Pt-based DSSC (6.1 ± 0.002%). The better electro-catalytic ability of Fe2(MoO4)3/RGO electrode is obtained by a synergistic effect that resulted in the high specific surface area and intrinsic reactivity of the materials.

Efficient wide-spectrum dye-sensitized solar cell by plasmonic TiN@Ni-MXene as electrocatalyst

Herein, dispersed Ni species over the surface of plasmonic TiN nanocrystals (TiN@Ni) are manufactured by using wetness impregnation method. This developmental material holds abundant surface sites and local surface plasmon resonance property. To further satisfy the requirement as the electrocatalyst for dye-sensitized solar cell (DSSC), bifunctional TiN@Ni nanocrystals are incorporated with monolayer MXene to construct the continuous conductive matrix. The yielded TiN@Ni-MXene film serves as counter electrode, power conversion efficiency(PCE) of corresponding DSSC under conventional irradiation condition is 8.08%, which surpasses as-reference Pt-based DSSC(7.59%). When further adding the NIR irradiation from counter electrode side of device, DSSC achieves an impressive PCE of 8.45%. The superior performance of TiN@Ni-MXene electrode should be attributed to the created active sites on the surface of TiN support, and the plasmonic effect from TiN@Ni nanoparticles via utilizing NIR light. Ni species provide more adsorption sites for triiodide ions, meanwhile the elevated temperature from plasmon-induced photothermal effect can effectively boost the triiodide reducing reaction rates at the interface of electrode and electrolyte. Thus electrocatalytic performance of TiN@Ni-MXene counter electrode is remarkablely enhanced. The strategy here will be beneficial for the design of highly active and stable electrocatalyst for DSSC, as well as realizing the efficient utilization for wide-spectrum solar energy.

Optimized photoelectric catalysis with enhanced durability in rGO-interconnected nanocarbon-confined cobalt nanoparticles

Rational construction of the electrocatalytic centers is effective yet challenging for designing the high-efficient-stable counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). Herein, the Prussian blue analogue (PBA)-derived nanocarbon-confined cobalt nanoparticles were successfully interconnected by the reduced graphene oxide network (Co-NC@rGO-600), and employed as the CE. In this interconnecting-and-confining scenario, the ambient graphitic carbon-shell and rGO network not only establish a communicating charge transfer bridge, but also greatly hinder the corrosion of the cobalt core in iodine electrolyte, thus endowing the catalyst with fast reaction kinetics and fine durability. Simultaneously, the nanocarbon-concentrated cobalt active core ensures the composite extraordinary catalytic activity towards the triiodide/iodide redox couple. Finally, the DSSC fabricated with Co-NC@rGO-600 realized a higher power conversion efficiency (PCE = 8.82%) than that of the commercial Pt-based DSSC (7.79%). These results deliver a new avenue to design the promising carbonaceous CE catalyst with optimized active centers, which may play a vital role in DSSCs and wider energy applications.

CoSe2/graphene composite: a low-cost, high performance counter electrode for dye sensitized solar cells

In this study, Pt-free dye-sensitized solar cells (DSSCs) were fabricated using cobalt selenide (CoSe2)/graphene sheets using facile hydrothermal technique. The Pt free counter electrode (CE) was systematically investigated their physico-chemical properties by using SEM, TEM, XRD, Raman, UV, PL, XPS and BET analysis. Under typical AM 1.5G illumination, the DSSC based on the CoSeSe2 counter electrode achieves a maximum PCE of 12.2 % (Jsc = 22.3 mA/cm2, Voc= 810 mV, and FF= 0.71), which is 5.8 times higher than that of conventional Pt-based DSSC. The improved electro catalytic activity and photo conversion efficiency of the CoSeSe2/graphene CE is due to prevent the recombination of electron-hole pair and extended the visible light absorption of composite samples.

Solution processed Cu2ZnSnSe4 nanoink for inexpensive Pt-free counter electrode in dye-sensitized solar cells

Morphology controllable Cu2ZnSnSe4 (CZTSe) nanoparticles (NPs) were successfully synthesized through hot injection method using oleic acid as solvent. The crystalline phase of the as-synthesized CZTSe NPs was confirmed with powder X-ray diffraction (XRD) and Raman results. The optical absorption spectra of CZTSe NPs exhibit a band gap of 1.21 eV. SEM analysis showed interconnected nanoflake-like morphology with higher surface area. The solid-state ligand exchanged CZTSe thin film without any toxic selenization process was used as counter electrode (CE) in dye-sensitized solar cells (DSSCs). The electrocatalytic activity of the CZTSe thin film for the reduction of iodide (I3−/I−) electrolyte was studied through cyclic voltammetry (CV) measurements. The DSSCs with ligand exchanged CZTSe CE exhibit an efficiency of 3.9% under 1 sun illumination, which is found to be higher than the Pt-based DSSC (3.5%) prepared in the same lab.

Efficient carbon counter electrodes for BaSnO3-based dye-sensitized solar cells

Natural source derived carbon materials make them ideally suited alternative to costly Pt counter electrode for their good catalytic activity, resistance to iodine corrosion, and high stability of the device. Apart from the extensively acclaimed photoanode TiO 2 , BaSnO 3 (BSO) has been projected as an efficient alternative to it. In this study, remarkable efforts have been endeavoured to establish BSO-carbon-based dye-sensitized solar cell (DSSC) device. Investigation on the adequate performance of natural source derived carbon-based counter electrodes for BSO-based DSSCs, explored as a significant alternative to costly Pt and TiO 2 , respectively, which could elucidate better photo-stability and more extended device performance compared to TiO 2 -Pt-based DSSCs.

Facile fabrication of reduced graphene oxide counter electrodes by laser engraver for dye-sensitized solar cell applications

Exploring alternative Pt-free counter electrode with low cost and high electrocatalytic activity is always a main focus at the frontier of dye-sensitized solar cells (DSSCs). In this study, a desktop laser engraver was applied to reduce graphene oxide (GO) film on a fluorine-doped tin oxide (FTO) substrate, and the obtained graphene-based material was further used as counter electrode for DSSC. Additionally, this facile laser-scribing method was also adopted to fabricate a prototype of composite electrode via the combination of reduced graphene oxide (RGO) and carbon black (CB) to enhance the specific surface area and active sites. A variety of characterizations including scanning electron microscopy (SEM), Raman spectroscopy, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were conducted to investigate the microstructures and catalytic properties of these carbon electrodes. The findings reveal that both of the DSSCs with laser-scribed carbon electrodes show evidently increasing photovoltaic performance, and the DSSC based on RGO/CB composite electrode even presents a higher power conversion efficiency (PCE) of 4.49%, comparable to 4.14% of the conventional Pt-based DSSC.

Oleic acid-mediated synthesis of small-sized and monodisperse NiSe2 nanowires as counter electrode catalysts for triiodide reduction

Developing a low-cost counter electrode (CE) catalyst with outstanding catalytic activity for the triiodide (I3−) reduction reaction (IRR) in dye-sensitized solar cells (DSSCs) is highly desirable. Herein, small-sized NiSe2 nanowires (NiSe2-W) were controllable synthesized by introducing the oleic acid (OA) as organic capping ligand into reaction system. Similarly, the monodisperse NiSe2 nanoparticles (NiSe2-P) with the small-sized were prepared by the same synthesis strategy under the absence of OA. The difference in morphologies between NiSe2-W and NiSe2-P can be attributed to the anisotropy and the oriented attachment of OA, and then the possible growth mechanism of them had been proposed. On the basis of the unique 1D nanostructure and chemical composition merits, power conversion efficiency (PCE) of 8.78 % was achieved when the NiSe2-W exploited as the CE catalyst for DSSCs, superior to that of the state-of-the-art Pt-based DSSCs (7.97 %) in parallel. Moreover, the relevant electrochemical measurements revealed that the as-prepared NiSe2-W displayed superior catalytic activity for IRR and good electrochemical durability in the redox electrolyte containing the I3−/I−. Then the NiSe2-W with unqiue 1D structure had been expected to replace Pt for the application of DSSCs, and could be a potential candidate in extensive new energy applications.

Development of MoSe2/PANI composite nanofibers as an alternative to Pt counter electrode to boost the photoconversion efficiency of dye sensitized solar cell

In this work, a simple hydrothermally prepared molybdenum diselenide (MoSe2) was mixed with polyaniline (PANI) nanofibers at 1:1 Wt% in deionized water by using an ultrasonicator for few minutes and then filtered and dried at 100 °C to get MoSe2/PANI composite nanofibers to use as a counter electrode (CE) for high-performance dye-sensitized solar cell (DSSC). The X-ray diffractometer (XRD) result confirms the formation of MoSe2/PANI composite nanofibers with high purity, which is consistent with the result of Raman spectrum. Field emission scanning electron microscopy (FE-SEM) studies confirm the decoration of MoSe2 nanoparticles onto the surface of polyaniline nanofibers and their chemical composition was calculated by energy-dispersive X-ray spectroscopy (EDX). The cyclic voltammetry (CV) study shows that MoSe2/PANI composite nanofibers as CE have good electrocatalytic activity, fast electron transport rate with increased current flow than the individual MoSe2 and PANI CEs. From AC-impedance analysis, it is cleared that MoSe2/PANI composite nanofibers based CE have lower charge-transfer resistance (Rct) with higher electrocatalytic behavior for I3−/I− redox pair than the pure MoSe2, PANI, and Pt-based CEs. Moreover, MoSe2/PANI composite nanofibers based DSSC show higher cell efficiency of 8.04% than the pure MoSe2, PANI, and Pt-based DSSCs. It revealed that MoSe2/PANI CE could be used as a promising candidate for DSSC.

A new electrochemically prepared composite counter electrode for dye-sensitized solar cells

In this paper, we propose new counter electrodes for applications in dye-sensitized solar cells (DSSCs). Polyaniline (PANi), tungsten trioxide (WO3), and their composite are deposited on indium thin oxide substrates using cyclic voltammetry technique and employed as counter electrodes that reached comparable and superior performances than Pt counter electrodes. These excellent results are achieved due to the high conductivity and electrocatalytic behavior of the prepared materials. Morphological, electrocatalytic, bonding structure, charge transfer properties, and photovoltaic characteristics are respectively investigated by field emission electron microscopy, cyclic voltammetry, Tafel analysis, Fourier-transform infrared spectroscopy, UV-visible spectroscopy, energy dispersive spectroscopy, electrochemical impedance spectroscopy, and current-voltage analysis. Our best DSSC that is fabricated from the WO3/PANi nanocomposite counter electrode demonstrated an efficiency of 6.78%, which is a 12.4% improvement in comparison with the Pt-based DSSC.

One-step electrodeposited CoSe2 nano-reticular with high electroconductivity and electrocatalytic as a counter electrode for dye sensitized solar cell

Abstract Herein, a nano-reticular structure cobalt diselenide (CoSe2) film with high electroconductivity and electrocatalytic has been synthesized by one-step electrodeposition method and is applied as a counter electrode for dye sensitized solar cell (DSSC). Cyclic voltammetry (CV) measurements with different potential windows are carried out to reveal the deposition mechanism of cobalt selenide, illustrating that the formation of CoSe2 occurred at −0.62 V via inductive effect reaction with selenide (Se2−). Tafel and CV characterizations demonstrate an excellent electrocatalytic activity of CoSe2 counter electrode towards I−/I3− reduction reaction, which is attributed to the electronic effect between Co and Se and electrochemical active sites, provided by wrinkled layer structure, for adsorption and reduction of I3−. EIS measurements show a great electroconductivity ability of electrodeposition CoSe2 film. The DSSC based on the CoSe2 counter electrode yields a maximum power conversion efficiency of 3.96% (Jsc = 10.84 mA cm−2, Voc = 0.65 V and FF = 55%) under the standard AM 1.5G illumination, which is 1.6 times higher than that of commercial Pt-based DSSC.

WN/nitrogen-doped reduced graphite oxide hybrids for triiodide reduction in dye-sensitized solar cells

The development of low-cost, environmental friendliness, outstanding catalytic activity, superior conductivity and good stability counter electrode (CE) catalyst in dye-sensitized solar cells (DSSCs) is important to promote the commercial application of DSSCs. Here, WN/nitrogen-doped reduced graphite oxide hybrids (WN/NrGO) had been synthesized by hydrothermal method followed by nitridation treatment, which used as CE catalysts for catalyzing I3− to I−. The combined WN and nitrogen-doped reduced graphite oxide (NrGO) into WN/NrGO could effectively regulate the catalytic activity for the reduction of I3−, accelerate the charge transfer at the interface, and then the synergistic effect between of them can be fully achieved. When the WN/NrGO served as the CE catalyst in DSSCs, the photoelectric conversion efficiency (PCE) of 7.42% has been obtained, compared to the conventional Pt-based DSSCs (7.71%). Meanwhile, as-prepared WN/NrGO exhibited higher PCE than that of the solo WN (6.19%) and NrGO (5.81%) in parallel. A series of electrochemical measures revealed that the WN/NrGO displayed the higher catalytic activity and charge transfer ability than that of the solo WN and NrGO, so the synthesized low-cost WN/NrGO have an potential to be used as the effectively CE catalysts for the replacement of the noble Pt.

Synthesis of MoS2–MoO2/MWCNTs counter electrode for high-efficient dye-sensitized solar cells

In this work, MoS2–MoO2 and MoS2–MoO2/MWCNTs counter electrodes (CEs) for dye-sensitized solar cells (DSSCs) were prepared by sulfurization of a one-pot hydrothermally obtained MoO2 film and MoO2/MWCNTs composite film on fluorine-doped tin oxide glasses at 500 °C for 2 h in argon atmosphere. The promoted MoS2 particles on a surface of MoS2–MoO2 and MoS2–MoO2/MWCNTs films were identified by X-ray diffraction to have a hexagonal structure. Morphology of MoO2, MoO2/MWCNTs, MoS2–MoO2, and MoS2–MoO2/MWCNTs CEs was studied using field emission scanning electron microscope and transmission electron microscope. Functional groups in MoS2–MoO2/MWCNTs sample were identified by Raman spectroscopy. Results of cyclic voltammetry and electrochemical impedance spectroscopy displayed a high electrocatalytic activity performance and low charge transfer resistance of MoS2–MoO2/MWCNTs CE as compared to those of MoO2, MoO2/MWCNTs, and MoS2–MoO2 CEs. Interestingly, the DSSC based on MoS2–MoO2/MWCNTs CE could provide the higher power conversion efficiency of 7.79% compared to that of 7.26% for Pt-based DSSC.

Dual functional application of pomelo peel-derived bio-based carbon with controllable morphologies: An efficient catalyst for triiodide reduction and accelerant for anaerobic digestion

Pomelo peel-derived bio-based carbon with controllable morphologies are successfully prepared by three different methods (microwave pyrolysis, two-step activation, hydrothermal carbonization combining chemical activation). The differences in specific surface area and pore size distribution caused by various morphology features remarkably affect the application potential of as-prepared bio-based carbon. Two-step activation carbonization is proven to be an effective and feasible method to synthesize small-size bio-based carbon with large specific surface area (1377.60 m2/g) and total pore volume (0.72 m3/g) as compared with other methods. The bio-based carbon prepared by two-step activation method as counter electrode catalyst in dye-sensitized solar cell (DSSC) obtains an excellent photovoltaic performance as compared with the Pt-based DSSC (6.94% vs. 6.71%). Furthermore, the as-prepared bio-based carbon is used as accelerant in anaerobic digestion (AD) systems and obtains the enhanced cumulative biogas production (525 mL/g VS) and chemical oxygen demand removal rate (70.95%) as compared with the control check group (296 mL/g VS, 29.55%). This work illustrates three promising methods to prepare bio-based carbon with controllable morphologies and superior surface area for realizing their multifunction resource utilizations in renewable energy fields.

Activated charcoal and reduced graphene sheets composite structure for highly electro-catalytically active counter electrode material and water treatment

In quest of finding a sustainable solution for metal-free counter electrode materials, reduced graphene oxide (rGO) is emerged as the best alternative due to its intrinsic high electrocatalytic activity. However, owing to its two-dimensional sheets like structure, there is re-stacking of rGO sheets, which reduces exposed surface area and hinders in electrolyte diffusion. To avoid these issues, activated charcoal (AC) is explored as an active spacer material between rGO sheets, for the first time. By loading an optimum concentration of AC in rGO, a high porosity, high conductivity, and high concentration of active sites were gathered in the single composite structure. Such synchronized features of the proposed composite were utilized for Pt-free counter electrode application in dye-sensitized solar cell (DSSc). The composite structure showed high electrocatalytic activity, with a low charge transfer resistance of 0.7 Ω, which is far lower than Pt and rGO (8.5 Ω and 7.5 Ω). The DSSc fabricated with optimized composite showed power conversion efficiency of 8.6%, compared to Pt-based DSSc with 7.9% efficiency. Additionally, the potential of the electrode was also tested for the electro-photocatalytic (99%) degradation of methylene blue dye from water, in 60 min. The proposed highly efficient nanocomposite structure possesses the highest efficiency as compared to other previously studied rGO based counter-electrodes.

Synthesis of Surfactant-Free and Morphology-Controllable Vanadium Diselenide for Efficient Counter Electrodes in Dye-Sensitized Solar Cells.

In this study, a transition-metal selenide, vanadium diselenide (VSe2), with various morphologies was synthesized by employing a surfactant-free hydrothermal method under varied temperature conditions (190-220 °C). Although the physical properties of VSe2 have been studied before, only limited morphological change or application were explored. This study, for the first time, applied VSe2 as the electrocatalytic counter electrode (CE) in dye-sensitized solar cells (DSSCs) and showed an attractive cell efficiency. The mechanism of forming the tunable VSe2 morphologies is proposed. The evaluation of solar cell efficiency shows the correlation between morphology and electrocatalytic properties. It was further shown that VSe2-200 with the cauliflower-like morphology shows the highest cell performance of DSSC with an efficiency of 9.23 ± 0.07% under 1 sun irradiance, superior to that of the Pt-based DSSC (8.48 ± 0.08%). An electrochemical technique equipped with a rotating disk electrode system was introduced to confirm the high electrocatalytic performance with this particular morphology. The optimized VSe2 demonstrated good long-term stability with 78% retention after 500 cycles of the consecutive cyclic voltammetry, compared to 60% for the Pt CE. The control in morphology in vanadium diselenide synthesis and its usage in Pt-free CE DSSC have advanced the progress in electrochemistry.

Synthesis of Porous NiMo Sulfide Microspheres for High-Performance Dye-Sensitized Solar Cells and Supercapacitor

Novel hierarchical porous NiMoS4 microspheres with high electrochemical performance was successfully prepared using a facile one-step hydrothermal method. The dual application of porous NiMoS4 microspheres in energy harvesting and storage (i.e., dye-sensitized solar cells (DSSCs) and supercapacitors (SCs), respectively) is explored. In contrast to NiS2 nanosheets, MoS2 nanosheets and Pt counter electrodes (CEs), the NiMoS4 microspheres CE demonstrated the lowest charge transfer resistance and highest electrocatalytic activity for the I[Formula: see text]/I− redox couple reaction. The NiMoS4-based DSSC showed a higher power conversion efficiency (8.9%) even than that of Pt-based DSSC (8.7%) under simulated standard global AM 1.5[Formula: see text]G sunlight (100[Formula: see text]mW[Formula: see text]cm[Formula: see text]). As an electroactive material for SCs, the assembled NiMoS4//AC asymmetric supercapacitor showed excellent specific capacitance (118.7[Formula: see text]F[Formula: see text]g[Formula: see text] at 1[Formula: see text]A[Formula: see text][Formula: see text], high energy density of 42.2[Formula: see text]Wh[Formula: see text]kg[Formula: see text] (with a power density of 799.2[Formula: see text]W[Formula: see text]kg[Formula: see text], and superior cycling durability with a specific capacitance retention of 79.5% after 9000 cycles at 3[Formula: see text]A[Formula: see text]g[Formula: see text].

Hierarchical Fe3O4-reduced graphene oxide nanocomposite grown on NaCl crystals for triiodide reduction in dye-sensitized solar cells

Cost-effective reduced graphene oxide sheets decorated with magnetite (Fe3O4) nanoparticles (Fe3O4-rGO) are successfully fabricated via a chemical vapor deposition (CVD) technique using iron (III) nitrate as an iron precursor, with glucose and CH4 as carbon sources, and NaCl as a supporting material. TEM analysis and Raman spectroscopy reveal hierarchical nanostructures of reduced graphene oxide (rGO) decorated with Fe3O4 nanoparticles. Fe K-edge x-ray absorption near edge structure (XANES) spectra confirm that the nanoparticles are Fe3O4 with a slight shift of the pre-edge peak position toward higher energy suggesting that the fabricated Fe3O4 nanoparticles have a higher average oxidation state than that of a standard Fe3O4 compound. The hierarchical Fe3O4-rGO is found to exhibit an excellent catalytic activity toward the reduction of triiodide to iodide in a dye-sensitized solar cell (DSSC) and can deliver a solar cell efficiency of 6.65%, which is superior to a Pt-based DSSC (6.37%).