Zhao Jujiao, Shang Bo, Zhai Jun
College of Environment and Ecology & MOE Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Chongqing University, Chongqing 400045, China.
School of Chemistry and Chemical Engineering & Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 401331, China.
Nanomaterials (Basel). 2021 Sep 17;11(9):2418. doi: 10.3390/nano11092418.
N-doped graphene samples with different N species contents were prepared by a two-step synthesis method and evaluated as electrocatalysts for the nitrate reduction reaction (NORR) for the first time. In an acidic solution with a saturated calomel electrode as reference, the pyridinic-N dominant sample (NGR2) had an onset of 0.932 V and a half-wave potential of 0.833 V, showing the superior activity towards the NORR compared to the pyrrolic-N dominant N-doped graphene (onset potential: 0.850 V, half-wave potential: 0.732 V) and the pure graphene (onset potential: 0.698 V, half-wave potential: 0.506 V). N doping could significantly boost the NORR performance of N-doped graphene, especially the contribution of pyridinic-N. Density functional theory calculation revealed the pyridinic-N facilitated the desorption of NO, which was kinetically involved in the process of the NORR. The findings of this work would be valuable for the development of metal-free NORR electrocatalysts.
采用两步合成法制备了具有不同氮物种含量的氮掺杂石墨烯样品，并首次将其作为硝酸盐还原反应（NORR）的电催化剂进行评估。在以饱和甘汞电极为参比的酸性溶液中，吡啶氮占主导的样品（NGR2）的起始电位为0.932 V，半波电位为0.833 V，与吡咯氮占主导的氮掺杂石墨烯（起始电位：0.850 V，半波电位：0.732 V）和纯石墨烯（起始电位：0.698 V，半波电位：0.506 V）相比，显示出对NORR具有更高的活性。氮掺杂可显著提高氮掺杂石墨烯的NORR性能，尤其是吡啶氮的贡献。密度泛函理论计算表明，吡啶氮促进了NO的脱附，这在动力学上参与了NORR过程。这项工作的发现对于无金属NORR电催化剂的开发具有重要价值。
