Direct growth of TiO2–MoO2/MnO2–MoO2 on plasma-treated carbon-cloth surface for high-performance supercapacitor and oxygen evolution reaction

Abstract

The present work focuses on the amendment of the carbon cloth (CC) surface and the functionalization of TiO2-MoO2/MnO2-MoO2 for high-performance symmetric supercapacitors and the oxygen evolution reaction (OER). The oxygen plasma treatment activated the CC, and the TiO2-MoO2/MnO2-MoO2 materials were directly functionalized onto the CC surface to obtain the target materials (CC-TiO2-MoO2 and CC-MnO2-MoO2). The functionalization of TiO2-MoO2/MnO2-MoO2 on CC was confirmed by P-XRD, XPS, Raman, and ATR-FTIR spectroscopy techniques, and the surface morphologies of the materials were studied using FE-SEM and AFM. The bimetallic oxide materials were strongly attached to the surface of the activated CC and were sufficiently rich for stable charge-transfer of electrons to the electrode material. Using a three-electrode system, the specific capacitances of CC-TiO2-MoO2 and CC-MnO2-MoO2 were found to be 506 and 1501.66 mF cm–2, respectively, at 1 mA cm–2. For the two-electrode system, the specific capacitances were 172.3 and 232.5 mF cm–2, respectively, at 1 mA cm–2. The energy and power densities were 55.09 and 73.7 μWh cm–2, respectively, for CC-TiO2-MoO2, and 10,222.94 and 9055.41 μWh cm–2, respectively, for CC-MnO2-MoO2. Moreover, the Ti- and Mn-based electrodes showed ideal cyclic stabilities of 94% and 95%, respectively, over 5000 galvanostatic charge/discharge (GCD) cycles. The two prepared materials were also effective for alkaline-mediated (1 M KOH) OER at the lowest onset potentials of 1.51 V and 1.62 V, respectively, and delivered a stable current density of 10 mA cm–2 in 1.0 M KOH for 10 h. This work achieves the direct growth of bimetallic oxide materials on the surface of the activated CC. The prepared materials are suitable for binder-free, symmetrical high-performance supercapacitors and OER applications.