UNI-MB - logo
UMNIK - logo
 
E-viri
Celotno besedilo
Recenzirano Odprti dostop
  • Improving the Stability, Se...
    Siritanaratkul, Bhavin; Sharma, Preetam K.; Yu, Eileen H.; Cowan, Alexander J.

    Advanced materials interfaces, 05/2023, Letnik: 10, Številka: 15
    Journal Article

    Electrolyzers for CO2 reduction containing bipolar membranes (BPM) are promising due to low loss of CO2 as carbonates and low product crossover, but improvements in product selectivity, stability, and cell voltage are required. In particular, direct contact with the acidic cation exchange layer leads to high levels of H2 evolution with many common cathode catalysts. Here, Co phthalocyanine (CoPc) is reported as a suitable catalyst for a zero‐gap BPM device, reaching 53% Faradaic efficiency to CO at 100 mA cm−2 using only pure water and CO2 as the input feeds. It is also shown that the cell voltage can be lowered by constructing a customized BPM using TiO2 water dissociation catalyst, however this is at the cost of decreased selectivity. Switching the pure‐water anolyte to KOH improved both the cell voltage and CO selectivity (62% at 200 mA cm−2), but cation crossover could cause complications. The results demonstrate viable strategies for improving a BPM CO2 electrolyzer toward practical‐scale CO2‐to‐chemicals conversion. CO2 electrolyzers are usually operated with a high local pH at the cathode but this can cause issues with bicarbonate salt formation. Operating with a low local pH is desirable but challenging as H2 evolution can occur. Here, it is shown that a Co molecular catalyst performs with high selectivity and CO2 utilization in a zero‐gap bipolar membrane electrolyzer cell.