Boosting the physico-chemical and charge transfer characteristics in Zn1-xTMxO nanostructures for enhanced photocatalytic and photoelectrochemical activities

Abstract

Wurtzite Zn1-xTMxO nanostructures were solution processed for treating industrial effluents and as photo electrocatalysts for water splitting reactions. The influence of transition metals (TM: Ni, Cr, Co, Mn and Hf) on the physical and chemical properties of host semiconductor was initially adjudged through several analytical tools. The morphological evolution of Zn1-xTMxO nanostructures was noted to be evolved in form of nanoparticles and nanorods, depending on the traits of substituting ions. The nature of substitution and interaction of dopant metal ions within Zn1-xTMxO was evaluated through X-ray photoelectron spectroscopic (XPS) measurements. Absorbance data suggested the tunability in optical band gap and absorbance values of Zn 1-xTMxO as a function of the dopant ions. Likewise, the emission spectra affirmed the potential of dopant ions to suppress the defect related emissions in Zn1-xTMxO. The photocatalytic efficacy was noted to be significantly higher in Co doped samples from the results obtained through comparative dye degradation studies using all the processed nanomaterials. A similar trend was also observed in the PEC investigations through time-dependent photocurrent density outputs. The electrochemical impedance data collectively emphasized the Co ions to induce the effective separation of charge carriers in Zn1-xTMxO via improved electronic conductivity.

Keywords

• Transition metal
• ZnO
• Nanostructures
• Photocatalytic
• Photoelectrochemical