Remarkable Enhancement in the Photoelectric Performance of Uniform Flower-like Mesoporous Fe₃O₄ Wrapped in Nitrogen-Doped Graphene Networks

Abstract

The porous structure and excellent specific surface area are superior for use as a counter electrode (CE) material. In addition, N-doped graphene possesses a remarkable electron-transfer pathway and many active sites. Therefore, a novel idea is to wrap uniform flower-like mesoporous FeO (FeOUFM) in an N-doped graphene (N-RGO) network structure to enhance the power conversion efficiency (PCE). The hybrid materials of FeOUFM@N-RGO are first used as a CE in dye-sensitized solar cells (DSSCs), showing a preeminent conductive interconnected 3D porous structure with more catalytic activity sites and a better ability for and a faster reaction rate of charge transfer, resulting in quicker reduction of I than Pt. A 9.26% photoelectric conversion efficiency has been achieved for the DSSCs with FeOUFM@N-RGO as the CE, which is beyond the value of Pt (7.72%). The positive synergetic effect between FeO and N-RGO is mainly responsible for the remarkable photoelectric property enhancement of this uniform flower-like mesoporous FeO wrapped in N-doped graphene networks, as demonstrated by the Tafel polarization, electrochemical impedance spectra, and CV curves. These methods will provide a simple way to effectively reproduce CE materials.

α-Fe2O3 hollow meso–microspheres grown on graphene sheets function as a promising counter electrode in dye-sensitized solar cells

“…Further, in the aspect of characterizing the performance of the electrode materials, according to eqn (1) and (2) , J 0 indicates the electron-exchange ability and is inversely proportional to R ct , whereas J lim indicates the ionic diffusion coefficient between the two identical electrodes. 26 Consistent with the results of EIS, the J lim and J 0 values of Fe 2 O 3 /RGO HMM were also found to be close with those of Pt electrode. J 0 = RT / nFR ct J lim = 2 neDcN A / l where R is the gas constant, T is the temperature, n is the number of electrons in the reduction of I 3 − , F is the Faraday constant, D is the diffusion coefficient of triiodide, l represents the electrode spacing, C is the concentration of triiodide, and N A is the Avogadro's constant.…”

Ultralong NiSe nanowire anchored on graphene nanosheets for enhanced electrocatalytic performance of triiodide reduction

“…Meanwhile, the limiting diffusion current density ( J lim ) can be obtained from the y -intercept of the cathodic branch. 43,44 The obtained J 0 and J lim values are summarized in Table 1 . The NiSe NW/RGO yielded a higher J 0 (0.80 mA cm −2 ) than NiSe NW (0.54 mA cm −2 ) and Pt (0.69 mA cm −2 ) CEs, revealing that the intrinsic electron-transfer ability was higher in NiSe NW/RGO than in the other CE.…”

Nonsiliceous Mesoporous Materials: Design and Applications in Energy Conversion and Storage

“…Mesoporous Ni 0.85 Se nanospheres grown on graphene enabled more catalytically active sites, a better charge transfer ability, and a faster reaction velocity . Uniform flower‐like mesoporous Fe 3 O 4 wrapped in a N‐doped graphene network structure had an extensive conductive interconnected 3D porous structure …”