Morphology-dependent catalysis on nanostructures Fe2O3@MWCNT as Pt-free counter electrode for dye-sensitized solar cells

The doped transition metal oxides (TMOs) substitute for the traditional Pt as the counter electrode (CE) catalyst is a unique way to reduce the cost and improve the power con-version efficiency (PCE) of dye-sensitized solar cells (DSSCs). Herein, four different morphologies and size of Fe2O3 (nanodiscus (ND), nanocubes (NC), nanorings (NR), nanoball (NB)) assisted by multi-walled carbon nanotube (MWCNT) to prepare Fe2O3@MWCNT composites, and then were further utilized in the encapsulated DSSCs. The obtained different morphologies Fe2O3@MWCNT composites had been characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and N2 adsorption-desorption. The significant effects of different morphologies of Fe2O3 on the electrochemical activity of Fe2O3@MWCNT composites as CEs were confirmed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel polarization experiments. The DSSCs using Fe2O3@MWCNT composites CEs achieved high PCEs of 6.34 (ND), 6.53(NC), 6.65(NR), and 7.09% (NB) to regenerate traditional I3 -/I- shuttles by the photocurrent-photovoltage (J-V) test, respectively, which is due to the synergistic effect between Fe2O3 and MWCNT to improve electrical conductivity and promote a high number of active catalytic sites, implying a remarkable alternative of Pt-free catalyst that can be applied to the encapsulated DSSCs as CEs.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The study investigates the use of doped transition metal oxides (TMOs) as substitutes for traditional Pt in dye-sensitized solar cells (DSSCs) to improve power conversion efficiency (PCE) and reduce cost. Fe2O3@MWCNT composites with different morphologies are prepared and utilized as counter electrodes (CEs) in encapsulated DSSCs. The effects of morphologies of Fe2O3 on the electrochemical activity of Fe2O3@MWCNT composites are confirmed. The DSSCs using Fe2O3@MWCNT composites CEs achieve high PCEs, indicating a remarkable alternative of Pt-free catalyst for encapsulated DSSCs.