The growing amount of carbon dioxide emission in parallel with the increasing greenhouse effect have put the utilization of carbon dioxide in the focus of scientific interest in the past decade. Photoelectrochemical (PEC) conversion of CO2 is a thermodynamically uphill reaction, raising multiple requirements, which a good photoelectrode has to concurrently fulfill. Not surprisingly, as of yet, there is no single material which bears with all the necessary properties. We have demonstrated recently that not only inorganic semiconductors (SCs) can be utilized for this purpose, but also conducting polymers (CPs), for e.g., polyaniline. At the same time polyaniline suffers from multiple handicaps, such as relatively small photocurrents and instability. Both of these can be traced back to the small charge carrier mobility, which results in extensive recombination. A viable way is to deposit the CP on a conducting nanonetwork, such as carbon nanotubes or graphene. This way the charge carrier pathway is decreased both to the current collector and to the electrode/electrolyte interface, which in turn results in higher currents and maybe different products that we experienced in the case of the bare CP. In my presentation I am showing the PEC behavior of polyaniline/ultra-long carbon nanotubes (ULMWCNT) and polyaniline/graphene nanohybrid photoelectrodes in the PEC reduction of CO2 with various polymer/carbon ratios. The composition of these nanocomposites has been optimized from both the thickness of the nanocarbon and the polymer layer. The effect of the nanocarbon networks on the morphology, photocurrents, stability and products were investigated by several techniques, such as: SEM, TEM, Raman spectroscopy, linear sweep photovoltammetry, chronoamperometry, EIS, GC, and GC-MS.

Photoelectrocatalytic reduction of CO2 on organic/inorganic nanocomposite photoelectrodes

253rd National Meeting (2017)

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