High Catalytic Activity of W₁₈ O₄₉ Nanowire-Reduced Graphite Oxide Composite Counter Electrode for Dye-Sensitized Solar Cells

Abstract

The W18O49 nanowire (NW)‐reduced graphite oxide (W18O49‐rGO) nanocomposite was prepared by a facile solvothermal reaction. The W18O49 NWs were stably dispersed on the surface of rGO, and the content of W18O49 NWs in the composite can be tailored by controlling the mass ratio of reactants (WCl6 and graphite oxide). Employing the W18O49‐rGO nanocomposite with the proper W18O49 NW content of 33% as a counter electrode of dye‐sensitized solar cells (DSSCs), it gets a photoelectrical conversion efficiency (η) of 7.23%, which is close to that of Pt‐based DSSC (7.39%). The high efficiency of DSSCs based on W18O49‐rGO counter electrode is contributed to the intrinsic electrocatalytic activity of W18O49 NWs and excellent electron‐transfer characteristics of rGO. The first‐principles calculations have been first employed to investigate the adsorption energy between I3− molecule and W18O49 NW to explain its good catalytic activity. The cyclic voltammetry (CV), electrochemical impedance spectra (EIS), and Tafel polarization tests can further identify that the W18O49‐rGO counter electrode has high electrocatalytic activity for the reduction of I3− and low interface charge transfer impedance. It is believed that the W18O49‐rGO nanocomposite can be used as a promising counter electrode material for DSSCs.

Rational Design of Metal Oxide–Based Cathodes for Efficient Dye‐Sensitized Solar Cells

“…2. [95,101,[103][104][105]107,108,110,117,129,130,134,152,154,155,157,158,161,169,[172][173][174]181,183,189,190,[197][198][199][200][201][202] In many cases, nanostructured metal oxide/carbon composite showed much higher PCEs, outperforming that of DSSC with Pt CE at the same condition. Such composites successfully utilized the advantages of sufficient conductivity and high activity of carbons and metal oxides, respectively.…”

“…Therefore, it is critical to design new electrocatalysts with well-controlled morphology that satisfy all of these requirements. [188][189][190] W 18 O 49 nanofibers (NFs), nanofiber bundles (NFBs) and hierarchical spheres (HSs) were synthesized via a solvothermal approach. [191] The morphologies of W 18 O 49 were well controlled by tuning the WCl 6 amount in the ethanol solvent.…”

High-Efficiency Dye-Sensitized Solar Cells Based on Kesterite Cu2ZnSnSe4 Inlaid on a Flexible Carbon Fabric Composite Counter Electrode

“…As a core component in dye-sensitized solar cells (DSSCs), the cathode should possess two basic characteristics of high conductivity and catalytic activity toward I – /I 3 – redox couple, responsible for transfer of the electrons from the external circuit to the redox electrolyte and then catalysis of the reduction of the redox species. − In recent research related to DSSCs, especially in counter electrodes (CEs), many studies were devoted to acquire high-efficiency and long-term stable DSSC devices based on Pt-free CEs. Therefore, several feasible approaches have been developed, such as (1) choosing alternative carbon, , conductive polymer, and inorganic transition-metal compound (TMC) catalytic materials − and (2) incorporating a TMC or conductive polymer with carbon-based materials, for instance, carbon fibers, carbon nanotubes, , graphene, reduced graphene oxide, , carbon black, and carbon fabric (CF). − CF, having benefits of large exposed area, high-conductivity, flexibility, stability, lightweight, and good corrosion resistance toward electrolytes, has been generally applied to flexible and all-weather energy devices, such as supercapacitors, lithium-ion batteries, and DSSCs.…”

Enhanced Photocatalytic Property of γ-CsPbI3 Perovskite Nanocrystals with WS2

“…The large resistance of R sh‑2 gives rise to a serious impediment to carrier transport from ligands to the MB electrolyte and further decreases the amount of photogenerated carriers reacting with MB, which may be the reason for their restricted photochemical property (e.g., photocatalytic degradation property). By contrast, EIS spectra of γ-CsPbI 3 NCs fabricated with WS 2 reveal a sloped line in the low-frequency region and a semicircle in the high-frequency region, which is in accordance with the carrier-transfer reaction at the CsPbI 3 |WS 2 interface (shunt resistance R sh‑1 ) and Warburg impedance W s relevant to carriers at the WS 2 |MB electrolyte interface, respectively. − These phenomena indicate that the electrochemical performances are highly related to the interfacial carrier-transfer process and diffusion control. Consistent with the variation in Table S5, it is clear that an efficient charge-transfer process will lead to a small R sh‑1 , and γ-CsPbI 3 NCs and WS 2 form a heterostructure where γ-CsPbI 3 NCs grow in-situ on the surface of WS 2 , which is beneficial for carrier transport.…”