Peng Guiming, Wu Jiawen, Wang Mingzhan, Niklas Jens, Zhou Hua, Liu Chong
Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States.
Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.
Nano Lett. 2020 Apr 8;20(4):2879-2885. doi: 10.1021/acs.nanolett.0c00698. Epub 2020 Mar 26.
Identifying highly selective catalysts and accurately measuring NH yield without false-positives from contaminations remain two challenges in electrochemical nitrogen reduction reaction (NRR). Here, we report N-defective carbon nitride grown on carbon paper (CN/C) as a highly selective electrocatalyst. The NH yield was determined reliably by the slope of m-time plot rather than averaging the accumulated amount over time. Results showed the as-synthesized CN/C (synthesized at 600 °C) with a higher density of C=N-C N vacancies achieved an NH production of 2.9 μg mg h at -0.3 V (versus RHE), ∼5.7-fold higher than CN/C. The Faradaic efficiency for CN/C is among the highest of 62.1%, 33.9%, and 16.8% at -0.1 V, -0.2 V, and -0.3 V, respectively. The NH production was verified by isotope N experiments. Further increase of N-defects on CN/C using plasma etching led to higher NH yield than comparably larger current, pointing to N-defects sites for promoting NRR.
在电化学氮还原反应（NRR）中，识别高选择性催化剂以及准确测量NH产量而不出现来自污染物的假阳性结果仍然是两个挑战。在此，我们报道了生长在碳纸上的氮缺陷型氮化碳（CN/C）作为一种高选择性电催化剂。NH产量通过m - 时间图的斜率可靠地确定，而不是对随时间积累的量进行平均。结果表明，合成的CN/C（在600℃合成）具有更高密度的C=N - C - N空位，在-0.3 V（相对于可逆氢电极）下实现了2.9 μg mg⁻¹ h⁻¹的NH产量，比CN/C高约5.7倍。CN/C在-0.1 V、-0.2 V和-0.3 V时的法拉第效率分别为62.1%、33.9%和16.8%，是最高的之一。NH产量通过同位素¹⁵N实验得到验证。使用等离子体蚀刻进一步增加CN/C上的氮缺陷导致比相对较大电流更高的NH产量，表明氮缺陷位点促进了NRR。
