Photoelectrochemical performance of MWCNT-Ag-ZnO ternary hybrid: a study of Ag loading and MWCNT garnishing

摘要

Herein, by using chemical methods such as successive ionic layer adsorption and reaction (SILAR) and spin coating we have demonstrated a novel strategy for the synthesis of ternary hybrid to study photoelectrochemical (PEC) performance. To the best of our knowledge, for the first time we have represented a case study of achieving optimum SILAR cycles for Ag nanoparticles decoration on ZnO nanorods and a discussion was made on a role of multi-walled carbon nanotube (MWCNT) as a top layer over Ag-ZnO nanostructures for better PEC performance. Firstly, Ag nanoparticles loading over SILAR grown ZnO nanorods was varied for different SILAR cycles to optimize better photocurrent. This Ag-ZnO hybrid showed higher photocurrent density of 0.45 mA/cm(2) at 1 V bias (vs SCE) and photoconversion efficiency (PCE) of 0.21% (0.45 V vs SCE). Thereafter, MWCNTs were garnished by using spin coating as a top layer on Ag-ZnO hybrid leading to the formation of ternary hybrid of MWCNT-Ag-ZnO for further enhancement of PEC activity. We believe that top layer of MWCNT plays a vital role of electron and hole transfer and bridges Ag decorated ZnO nanorods together leading to well-connected conducting pathways for efficient charge collection and transport. The appropriate band bending of MWCNT-Ag-ZnO hybrid leads to the formation of active interface helping out in charge separation leading to excellent photocurrent density of 0.56 mA/cm(2) at 1 V bias (vs SCE) and photoconversion efficiency of 0.26% (0.45 V vs SCE).