Tuning Photo(electro)Catalytic Activity of Nano ZnO by Varying Current Density during Electrosynthesis

Zinc oxide (ZnO) remains a promising candidate in the field of photo(electro)catalytic hydrogen/electricity production from water/biomass and wastewater treatment. However, there has been a need for the development of sustainable, versatile tools for achieving controlled and economically viable production of nano ZnO. This research is aimed at assessing the electrochemical approaches to tune ZnO morphology through electrosynthesis using pulse alternating current (PAC) by varying the average anodic/cathodic current densities ratio (ja : jc) and NaCl electrolyte as one of the most naturally abundant compounds. The composition, morphology, and specific surface area (SSA) of the ZnO synthesized at different ja : jc were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), and low-temperature nitrogen adsorption-desorption (BET) methods. The synthesized ZnO nanopowders were applied as photoelectrocatalytic (PEC) and photocatalytic (PC) materials. PEC performance of ZnO/FTO was investigated using Na2SO3, ethanol, glycerol, ethylene glycol, formic acid, and glucose as inorganic and organic oxygenates. The PC activity of nano ZnO was evaluated using 2,4-dinitrophenol (DNP) as an organic pollutant. The variation in PEC and PC performance depending on the ZnO electrosynthesis conditions was shown.