Mixed metal oxides based on cobalt oxide are important target material as water oxidation catalyst in alkaline media. Significant enhancement of electrochemical oxygen evolution activity was observed for Au supported cobalt oxide, upon addition of Cr. CoO x /Au and Co[Cr]O x /Au were studied side by side to understand the effects of the addition of Cr in such a system. The presence of Cr resulted in a significant lowering of onset potentials~150 mV. In-situ Raman spectroscopy was used to characterize the material. The catalyst was found to develop into oxide entirely in situ. Cr was found to stabilize lower oxidation states of Co, both during catalyst formation and oxygen evolution. Isotopic substitution studies alongside in situ Raman Spectroscopy showed that OER onset potential strongly correlated with the appearance of metastable AuÀ OOH peak.

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The scalability and stability of electrocatalysts is one of the biggest challenges for their practical applicability. In this context, Co3O4 nanoparticles conformally coated on a light weight, 3D and highly conducting carbon cloth are fabricated using an easily synthesized cobalt hexadecylthiolate complex as ink. This method is especially useful for large‐scale production as the complex is synthesized in large quantities and coated on 3D substrates by a simple dip‐coating method. The optimum loading of the catalyst is achieved through a layer‐by‐layer (LbL) assembly of a cobalt hexadecylthiolate complex via repeated dip coating of the carbon cloth electrode in the solution. The Co3O4/CC undergoes electrochemical oxidation and converts to CoOOH as an active species and acts as a highly efficient electrocatalyst with optimized loading. The Co3O4‐16/CC with 16 times dip coating exhibits remarkable stability over 24 h with an overpotential of 300 mV at 10 mA cm−2 and a Tafel slope of 77.06 mV dec−1. The electrocatalytic activity of Co3O4‐16/CC prepared by LbL coating is better than conventional Co3O4 and comparable to IrO2 and RuO2 electrocatalysts with the future possibility of commercial‐scale production at lower cost.

Ni-YSZ-based electrodes are well-established in the field of solid oxide technologies. Ni/YSZ-based architectures have well-known performance and mechanical properties besides well-established manufacturing processes. Solid oxide-based CO2 electrolysis on Ni-YSZ at high temperature requires the presence of H2 in the CO2 inlet stream. It is believed that in pure CO2 streams the reaction fails due to oxidation of the Ni-YSZ electrode. Using operando Raman spectroscopy and online mass spectroscopy, we have shown that CO2 can in fact be reduced on the Ni-YSZ surface. Our measurements, reveal that Ni-YSZ oxidizes to NiOx-YSZ within a pure CO2 stream. CO2 electrolysis is possible on this oxide surface via a surface oxygen and vacancy-mediated mechanism similar to those observed within other oxide cathodes such as CeOx. The deactivation of the electrode coincides with strongly reducing conditions and at current densities > 400 mA/cm2, NiOx is completely reduced coinciding with complete stoppage of CO production. Cu-impregnation into Ni-YSZ was demonstrated to mitigate the deactivation issue by forming a more stable surface oxide on Ni which continued to carry out CO2 reduction under strongly reducing conditions. The new electrode demonstrated improved kinetics and stability against carbon deposition via Bouduard reaction.

Electroreduction of CO2 to fuels using renewable energy can significantly help in reducing emissions and dependence on fossil fuels. Electrochemical reduction of CO2 to hydrocarbon fuels (CHx) is energy inefficient owing to the multistep-multielectron transfer process, which possesses many kinetic limitations. The selective conversion of CO2 to CO is energy efficient. CO as product can be directly used as a fuel or converted to hydrocarbon fuels by using green hydrogen via Fischer-Tropsch reactions. We have used Ni(M)x/YSZ based electrodes to study electroreduction of CO2 on solid oxide cells at high temperature (~800∘C). Electrodes were developed on commercial standard YSZ supports using Ni(M)x/YSZ mixtures for cathode and LSM/YSZ mixtures for the anode. Electron microscopy and X-ray diffraction were used to characterize the electrode architecture and material. The electrodes were tested using online mass spectroscopy and operando Raman spectroscopy. Ni/YSZ electrodes showed sustained performance only when H2 was added to the fuel mixture, and the reaction proceeded through a reverse water gas shift reaction (RWGS) (CO2 + H2 → CO + H2O) in conjunction with water electrolysis with the CO originating from non-electrochemical RWGS reaction. The reactions were also analyzed using electrochemical impedance spectroscopy. The pure Ni/YSZ cathodes showed deactivation under a pure CO2 atmosphere with the formation of NiOx species with the catastrophic breakdown at high current densities around 400 mA/cm2. The behaviour could be verified using both mass spectroscopy and operando Raman Spectroscopy. The electrochemical performance of various electrodes was compared using a 3-electrode geometry. Mixed metal oxide electrodes such as Ni(M) showed improved kinetics, with significant improvement seen in the charge transfer resistance measured. Figure 1