Gold is known to be a poor electrocatalyst for oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER)/ hydrogen oxidation reaction (HOR). We have proposed theoretically and proved experimentally that the overpotentials for both ORR ad HER are decreased by the modification of Au electrode with boron nitride nanosheet (BNNS), an insulator, although ORR still proceeds by 2-electron process. We have recently demonstrated that the decoration of BNNS by gold nanoparticles (AuNPs: 5 ~ 30 nm) opens a 4-electron ORR route to water, although only ca. 50% of oxygen is reduced to water.  Here, we report that more than 80% of oxygen is reduced to water at the Au electrode modified by BNNS decorated with AuNPs of small size (ca. 5 nm) with narrow size distribution. Furthermore, the ORR overpotential is much less than that at the Au electrode modified by BNNS decorated with AuNPs of random size (5 - 30 nm) by 100-120 mV and is only 100 mV more than that at a Pt electrode.  We also found that AuNPs modification is effective for the reduction of HER overpotential. Amounts of Au can be reduced by using nanoparticles of Au alloys by other metals such as Ni.

Combination of insulating boron nitride and inert Au substrate as an efficient electrocatalysts for oxygen reduction reaction and hydrogen evolution reaction

2019 Spring National Meeting

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