09:30 〜 11:30
▼ [20a-PB9-5] Effect of Nitrogen Doping Amount on Electrocatalytic Activity of IrO2 on Nitrogen-doped Graphene for Excellent Oxygen Evolution Reaction
キーワード：oxygen reduction reaction, nitrogen-doped graphene, iridium oxide
Water splitting in water electrolyzers is an excellent green method to produce Hydrogen as an energy source. The anodic oxygen evolution reaction in water electrolyzers is a complex reaction with high overpotential and slow kinetics and requires metal oxide nanoparticles (nps) such as IrO2 as catalysts. However, due to low abundance and high cost, their extensive use is limited. In this regard, in the present work, we have evaluated the electrochemical activity of IrO2 nps supported on N-doped graphene with varying nitrogen amount.
The catalyst IrO2-N-rGO is synthesized via pyrolysis in Ar atmosphere and followed by loading of IrO2 on N-rGO via hydrothermal method using H2IrCl6 as the precursor. The extent of N-doping (1-8 wt%) was varied by changing the GO: urea weight ratio. XPS analysis of the synthesized IrO2-N-rGO catalyst revealed that N is present in its pyridinic and quaternary forms. TEM micrograph of IrO2-N-rGO catalyst showed well dispersed IrO2 nps all over the wrinkled N-rGO sheets without agglomeration with an average particle diameter of 1.5 nm. Electrochemical activity measured via CV and LSV methods showed that the onset potential (1.45 V vs RHE) was nearly 50 mV less than that of IrO2-rGO and higher current density was obtained for the synthesized catalyst as compared to the commercial IrO2 powder. IrO2-N-rGO with low Ir metal content and improved activity represents a potential low cost, robust candidate for OER catalytic applications.
The catalyst IrO2-N-rGO is synthesized via pyrolysis in Ar atmosphere and followed by loading of IrO2 on N-rGO via hydrothermal method using H2IrCl6 as the precursor. The extent of N-doping (1-8 wt%) was varied by changing the GO: urea weight ratio. XPS analysis of the synthesized IrO2-N-rGO catalyst revealed that N is present in its pyridinic and quaternary forms. TEM micrograph of IrO2-N-rGO catalyst showed well dispersed IrO2 nps all over the wrinkled N-rGO sheets without agglomeration with an average particle diameter of 1.5 nm. Electrochemical activity measured via CV and LSV methods showed that the onset potential (1.45 V vs RHE) was nearly 50 mV less than that of IrO2-rGO and higher current density was obtained for the synthesized catalyst as compared to the commercial IrO2 powder. IrO2-N-rGO with low Ir metal content and improved activity represents a potential low cost, robust candidate for OER catalytic applications.