Niobium doped TiO2 as oxygen evolution reaction electrocatalyst support in alkaline media has been successfully synthesized via a facile one-pot solvothermal synthesis. The prepared Nb-doped support (10% at., 20%at., 30% at. Nb doped TiO2) exhibit enhanced electronic conductivity ~10-3 to 10-2 S/cm and mesoporous structure with specific surface area of ~250 to 270 m2/g. The electronic conductivity is decreasing with the increasing amount of niobium since as the Nb amount is increased, the segregation becomes more severe. Electrochemical activity of Nb-doped TiO2 for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) was studied in 1 M KOH electrolyte by three-electrode cell set-up. The material generally shows better activity for ORR than OER based on the overpotential at onset. 10 at.% Nb-doped TiO2 (ST_T9N1) exhibits the best activity for both ORR and OER. Cobalt oxide as co-catalyst has been deposited on 10 at.% Nb-doped TiO2 (ST_T9N1) via three different one-pot hydrothermal processes. The obtained Co3O4 morphologies were particle, needle-like, and sheet-like. Their activities for ORR and OER were studied in 1 M KOH electrolyte by three-electrode cell set-up. All of the catalysts show higher activity for OER. The activity for OER was assessed based on three criteria: onset potential, current density at 1.65 V vs RHE and overpotential at 10 mA/cm2. The OER electrocatalytic activity order was sheet > needle > particle. OER electrochemical stability of the electrocatalysts was performed using potential cycling up to 1500th cycle. Current density loss after cycling was selected for stability evaluation. The order of current loss was Co3O4/ST_T9N1/C < RuO2 commercial < Co3O4/ST_T9N1. The addition of ECP300 (activated carbon) to the electrocatalyst further improves the activity and stability. The mechanism for the improvement in the activity and stability via the addition of activated carbon needs further investigation.

Niobium doped TiO2 as oxygen evolution reaction electrocatalyst support in alkaline media has been successfully synthesized via a facile one-pot solvothermal synthesis. The prepared Nb-doped support (10% at., 20%at., 30% at. Nb doped TiO2) exhibit enhanced electronic conductivity ~10-3 to 10-2 S/cm and mesoporous structure with specific surface area of ~250 to 270 m2/g. The electronic conductivity is decreasing with the increasing amount of niobium since as the Nb amount is increased, the segregation becomes more severe. Electrochemical activity of Nb-doped TiO2 for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) was studied in 1 M KOH electrolyte by three-electrode cell set-up. The material generally shows better activity for ORR than OER based on the overpotential at onset. 10 at.% Nb-doped TiO2 (ST_T9N1) exhibits the best activity for both ORR and OER. Cobalt oxide as co-catalyst has been deposited on 10 at.% Nb-doped TiO2 (ST_T9N1) via three different one-pot hydrothermal processes. The obtained Co3O4 morphologies were particle, needle-like, and sheet-like. Their activities for ORR and OER were studied in 1 M KOH electrolyte by three-electrode cell set-up. All of the catalysts show higher activity for OER. The activity for OER was assessed based on three criteria: onset potential, current density at 1.65 V vs RHE and overpotential at 10 mA/cm2. The OER electrocatalytic activity order was sheet > needle > particle. OER electrochemical stability of the electrocatalysts was performed using potential cycling up to 1500th cycle. Current density loss after cycling was selected for stability evaluation. The order of current loss was Co3O4/ST_T9N1/C < RuO2 commercial < Co3O4/ST_T9N1. The addition of ECP300 (activated carbon) to the electrocatalyst further improves the activity and stability. The mechanism for the improvement in the activity and stability via the addition of activated carbon needs further investigation.

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