Abstract
A procedure for the preparation of semiconductor anodes using mixed-metal oxides bound together and protected with a TiO2 nanoglue has been developed and tested in terms of the relative efficiencies of the oxygen evolution (OER), the reactive chlorine species evolution (RCS), and the hydrogen evolution (HER) reactions. The composition of the first anode is a Ti metal substrate coated with IrTaOx and overcoated with TiO2 (P25) that was mixed with TiO2 nanogel, while the second anode consists of a Ti metal substrate coated with IrTaOx and an over-coating layer of La-doped sodium tantalate, NaTaO3:La. The experimental efficiencies for water splitting ranged from 62.4% to 67.5% for H2 evolution and 40.6% to 60.0% for O2 evolution. The corresponding over-potentials for the Ti/IrTa-TiO2 and Ti/IrTa-NaTaO3:La anodes coupled with stainless steel cathodes of the same dimensions were determined to be 437 mV and 367 mV for the OER, respectively, and 239 mV and 205 mV for RCS, respectively. The preparation procedure described herein should allow for easier production of large-surface area anodes at lower costs than standard methods.
Highlights
We have recently developed prototype electrochemical reactor systems for the treatment of human or domestic wastewater that are powered by either AC or DC power sources [1,2,3,4]
In order to improve the efficiency of water splitting, it is essential to reduce the anodic overpotential for the oxygen evolution reaction (OER) by using optimized electron transfer catalysts
The electron probe microanalysis of the Ti-IrTa-NaTaO3 :La composite anode shows that the outermost surface of the anode consists of NaTaO3 :La mixed with nanoparticulate TiO2 in distinctly different size domains (Figure 2)
Summary
We have recently developed prototype electrochemical reactor systems for the treatment of human or domestic wastewater that are powered by either AC or DC power sources [1,2,3,4] In these electrochemical treatment systems, human wastewater is oxidized at an array of semiconductor anodes based on the generation rate of Reactive Chlorine Species (RCS), which is a key active compound in the process of wastewater treatment. The high cost of the iridium oxide precursor reagents coupled with the relatively poor long-term stability of IrO2 has essentially impeded the large-scale commercial application of DSAs. The process of attachment of nanoparticulate metal oxide semiconductors (e.g., IrO2 , RuO2 , Ta2 O5 , SnO2 , Bi2 O3 ) to base-metal surfaces is critical for producing efficient anodes and, in some cases, functionalized cathodes. Anatase (TiO2 ) nanogels have been reported to be a sticky inter-particle binding agent or nanoglue that results in improved electrochemical performance and higher current efficiencies for base-metal supported semiconductor anodes [10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
