Boosting the photoelectrochemical performance of ZnO nanorods with Co-doped Zn-ZIFs metal-organic frameworks for water splitting studies

Abstract

The present study sightsees the enhancement of photoelectrochemical (PEC) water splitting efficiency through the sensitization of ZnO nanorods (NRs) with bimetallic ZIFs, specifically Co@Zn-ZIFs metal-organic frameworks (MOFs). The incorporation of Co into Zn-ZIFs led to a stable and optically improved sensitizer for the said study. The sensitization of MOFs was carried out over different durations (6, 12, 18, and 24 h), to form the distinct ZnO/Co@Zn-ZIFs nanocomposites (NCs). The optimal NCs, obtained after 18 h of sensitization, i.e., ZnO/Co@Zn-ZIFs:18 hrs NCs exhibited a significant increase in current density of 0.62 mA/cm2 at 1.23 V vs. reversible hydrogen electrode (RHE) and a photoconversion efficiency (ABPE) of 0.071%, tripling the performance of bare ZnO NRs. This upgraded PEC performance of NCs is associated with enhanced optical properties, diminished charge transfer resistance (RCT: 44.27 Ω), high donor density (ND: 33.33 × 1026 cm−3), and active porous surface nature as verified using associated spectral/analytical tools. In addition, time series analysis (TSA) modeling was used to predict and forecast the stability associated with the optimized photoanode, which disclosed the decent stability of the photoanode over time. So present work reveals the amended PEC water splitting using an optimized ZnO/Co@Zn-ZIFs NCs having improved stability, optical characteristics, and active surface properties. © 2024 Hydrogen Energy Publications LLC