Graduate School of Chemical Sciences and Engineering, Hokkaido University , Sapporo 060-0810, Japan.
J Am Chem Soc. 2014 May 7;136(18):6542-5. doi: 10.1021/ja500393g. Epub 2014 Apr 28.
Boron nitride (BN), which is an insulator with a wide band gap, supported on Au is theoretically suggested and experimentally proved to act as an electrocatalyst for oxygen reduction reaction (ORR). Density-functional theory calculations show that the band gap of a free h-BN monolayer is 4.6 eV but a slight protrusion of the unoccupied BN states toward the Fermi level is observed if BN is supported on Au(111) due to the BN-Au interaction. A theoretically predicted metastable configuration of O2 on h-BN/Au(111), which can serve as precursors for ORR, and free energy diagrams for ORR on h-BN/Au(111) via two- and four-electron pathways show that ORR to H2O2 is possible at this electrode. It is experimentally proved that overpotential for ORR at the gold electrode is significantly reduced by depositing BN nanosheets. No such effect is observed at the glassy carbon electrode, demonstrating the importance of BN-substrate interaction for h-BN to act as the ORR electrocatalyst. A possible role of the edge of the BN islands for ORR is also discussed.
氮化硼（BN）是一种具有宽能隙的绝缘体，负载在金上被理论上和实验上证明可作为氧还原反应（ORR）的电催化剂。密度泛函理论计算表明，自由 h-BN 单层的带隙为 4.6eV，但如果 BN 负载在 Au(111)上，由于 BN-Au 相互作用，未占据的 BN 态会略微向费米能级突起。通过两电子和四电子途径在 h-BN/Au(111)上进行 ORR 的理论预测的 O2 的亚稳构型以及自由能图表明，在该电极上可以发生 ORR 生成 H2O2。实验证明，通过沉积 BN 纳米片可显著降低金电极上的 ORR 过电势。在玻璃碳电极上则观察不到这种效果，这表明 BN-基底相互作用对于 h-BN 作为 ORR 电催化剂的重要性。还讨论了 BN 岛边缘对 ORR 的可能作用。
