Enhanced chlorine evolution from dimensionally stable anode by heterojunction with Ti and Bi based mixed metal oxide layers prepared from nanoparticle slurry

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.