Sustainable Non-Noble Metal Bifunctional Catalyst for Oxygen-Depolarized Cathode and Cl2 Evolution in HCl Electrolysis

The composite of polyoxometalate [WZn3(H2O)2(ZnW9O34)2]12– (ZnPOM) with polyvinylidene-butyl-imidazolium cation (PVIM) and oxidized carbon nanotubes (OCNT) as non-noble metal bifunctional catalyst has been studied for oxygen-depolarized cathode (ODC) and Cl2 evolution in HCl electrolysis for the first time. The cyclic voltammetry and rotating disk electrode measurement analysis reveals superior activity of the composite as bifunctional catalyst for ODC and Cl2 evolution. Chronoamperometric experiments show high long-term stability, comparable to the state-of-art catalyst, even under multiple shutdown to open circuit potential. X-ray photoelectron spectroscopic studies after electrolysis (48 h) confirms no degradation of the composite and, hence, appears to be stable. Scanning electrochemical microscopy (SECM) measurements indicate that, even after 72 h of electrolysis, the composite retains high activity, similar to fresh composite.