Synergistic Interfacial Engineering of MoO3 Decorated MWCNT/g-C3N5 Nanohybrids toward High-Efficiency Sustainable Energy Devices

In this work, a new type of 0D/1D/2D face-to-face contact MoO3/MWCNT/g-C3N5 heterojunction was developed via a hydrothermal method. The ternary hybrid was constructed by coupling MoO3 nanoparticles with g-C3N5 nanosheets with MWCNT nanotubes sandwiched between them to form a 0D/1D/2D multinanostructure. The prepared MoO3/MWCNT/g-C3N5 materials were systematically investigated by using various characterization techniques, including XRD, FTIR, XPS, UV-DRS, PL, FE-SEM, and HR-TEM. The photovoltaic experiments were carried out using the prepared materials as counter electrodes in fabricated dye-sensitized solar cells (DSSCs). It was found that MoO3/MWCNT/g-C3N5 exhibited a significantly enhanced power conversion efficiency (7.58%) compared to pure MoO3 (2.93%) and the MoO3/MWCNT binary composite (5.85%). Moreover, the material exhibited excellent photovoltaic stability after 2 weeks. The underlying photovoltaic mechanism of MoO3/MWCNT/g-C3N5 was systematically investigated and discussed. The electrochemical properties of the prepared materials were examined through cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). MoO3/MWCNT/g-C3N5 showed excellent electrochemical performance. The specific capacitance of the MoO3/MWCNT/g-C3N5 electrodes was calculated to be 821.4 F/g. Furthermore, integrating the properties of 0D-MoO3, 1D-MWCNT, and 2D-g-C3N5 provided enhanced characteristics, including a wider absorbance range, a narrowed band gap, improved colloidal stability, superior electrochemical performance, and reduced charge-transfer resistance. These MoO3/MWCNT/g-C3N5 electrodes were successfully used in DSSCs and supercapacitors as promising and cost-effective alternatives to commercial electrodes.