State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China.
School of Chemical Sciences, The University of Auckland, Auckland, 1010, New Zealand.
Adv Sci (Weinh). 2022 Sep;9(27):e2201421. doi: 10.1002/advs.202201421. Epub 2022 Jul 28.
Electrochemical 2-electron oxygen reduction reaction (ORR) is a promising route for renewable and on-site H O production. Oxygen-rich carbon nanotubes have been demonstrated their high selectivity (≈80%), yet tailoring the composition and structure of carbon nanotubes to further enhance the selectivity and widen working voltage range remains a challenge. Herein, combining formamide condensation coating and mild temperature calcination, a nitrogen and oxygen comodified carbon nanotubes (N,O-CNTs) electrocatalyst is synthesized, which shows excellent selective (>95%) H O selectivity in a wide voltage range (from 0 to 0.65 V versus reversible hydrogen electrode). It is significantly superior to the corresponding selectivity values of CNTs (≈50% in 0-0.65 V vs RHE) and O-CNTs (≈80% in 0.3-0.65 V vs RHE). Density functional theory calculations revealed that the C neighbouring to N is the active site. Introducing O-related species can strengthen the adsorption of intermediates *OOH, while N-doping can weaken the adsorption of in situ generated *O and optimize the *OOH adsorption energy, thus improving the 2-electron pathway. With optimized N,O-CNTs catalysts, a Janus electrode is designed by adjusting the asymmetric wettability to achieve H O productivity of 264.8 mol kg h .
电化学 2 电子氧还原反应 (ORR) 是可再生和现场制 H2O 的有前途的途径。富含氧气的碳纳米管已经表现出高选择性（≈80%），然而，通过调整碳纳米管的组成和结构来进一步提高选择性并拓宽工作电压范围仍然是一个挑战。本文通过甲酰胺缩合涂层和温和的温度煅烧相结合，合成了一种氮氧共修饰的碳纳米管（N,O-CNTs）电催化剂，该催化剂在很宽的电压范围内（从 0 到 0.65 V 相对于可逆氢电极）表现出优异的选择性（>95%的 H2O 选择性）。它明显优于相应的 CNTs（≈50%在 0-0.65 V 相对于 RHE）和 O-CNTs（≈80%在 0.3-0.65 V 相对于 RHE）的选择性值。密度泛函理论计算表明，C 与 N 相邻的位置是活性位点。引入 O 相关物种可以增强中间体OOH 的吸附，而 N 掺杂可以削弱原位生成的O 的吸附，并优化*OOH 吸附能，从而提高 2 电子途径的选择性。通过优化 N,O-CNTs 催化剂，通过调整不对称润湿性设计了一个 Janus 电极，以实现 264.8 mol kg-1 h-1 的 H2O 产率。
