Abstract
This study reports enhanced current (CE(RCS)) and energy efficiency (EE(RCS)) of reactive chlorine species (RCS) generation on Ir(7)Ta(3)O(y) anode by Ti/Bi mixed metal oxide heterojunction layers despite reductions in pseudo-capacitance and film conductivity. In potentiostatic electrolysis of 50 mM NaCl solutions, dramatic improvement (0.61 mmol cm(-2) hr(-1) at 2.5 V NHE) was noted by simple coating of thin (~2 μm) TiO(2) layer from ball-milled TiO(2) nanoparticle (80-100 nm) suspension, even with moderate elevation in voltammetric wave. Decoration of Bi(2)O(3) particles (1 - 2 μm) showed limited or adverse effects for RCS generation and stability. However, Bi-doped TiO(2) layers prepared from polyol-mediated or co-precipitation methods marked the highest CE(RCS) (~100%) and EE(RCS) (8.16 mmol Wh(-1) at 2.5 V NHE) by increased mixing level and effective shift in surface charge. Surface ·OH exclusively mediated the RCS generation whose further transformation to higher oxide could be restrained by the heterojunction layer.