Zhu Jian, Hu Jing, Wang Zhenyu, Lu Zhouguang, Das Shoubhik, Cool Pegie
Department of Chemistry, University of Antwerp Antwerp 2610 Belgium
Department of Materials Science and Engineering, Southern University of Science and Technology Shenzhen 518055 PR China.
Chem Sci. 2025 Jan 7;16(6):2850-2860. doi: 10.1039/d4sc07354a. eCollection 2025 Feb 5.
Doping strategies have been recognized as effective approaches for developing cost-effective and durable catalysts with enhanced reactivity and selectivity in the electrochemical synthesis of value-added compounds directly from CO. However, the reaction mechanism and the specific roles of heteroatom doping, such as N doping, in advancing the CO reduction reaction are still controversial due to the lack of precise control of catalyst surface microenvironments. In this study, we investigated the effects of N doping on the performances for electrochemically converting CO to CO over Ni@NCNT/graphene hybrid structured catalysts (Ni@NCNT/Gr). Ni nanoparticles (Ni NPs) were encapsulated in N-doped carbon nanotubes (NCNTs) which were generated from g-CN during the annealing process due to the thermal catalysis of the existing Ni NPs. Our results show that the optimized pyrrolic N doping level, coupled with stable NCNT/Gr hybrid structures, high electrochemically active surface area, rich active sites, and reduced Ni NP size, synergistically contribute to the distinguished electrocatalytic performances. The as-prepared Ni@NCNT/Gr-R catalyst demonstrated a high CO faradaic efficiency (>90%) with negligible differences in CO FE across a wide potential range (-0.71--0.91 V RHE) in an H-cell while maintaining magnificent stability with negligible current density loss for 24 hours at -0.71 V ( RHE). Our findings provide evidence and insight into the optimization of pyrrolic N doping levels together with reducing NP size within the stable NCNT/Gr hybrid substrate for designing efficient CO reduction catalysts.
掺杂策略已被认为是开发具有成本效益且耐用的催化剂的有效方法，这些催化剂在直接由一氧化碳电化学合成增值化合物时具有更高的反应活性和选择性。然而，由于缺乏对催化剂表面微环境的精确控制，杂原子掺杂（如氮掺杂）在促进一氧化碳还原反应中的反应机理和具体作用仍存在争议。在本研究中，我们研究了氮掺杂对Ni@NCNT/石墨烯杂化结构催化剂（Ni@NCNT/Gr）上电化学将一氧化碳转化为一氧化碳性能的影响。镍纳米颗粒（Ni NPs）被封装在氮掺杂的碳纳米管（NCNTs）中，在退火过程中，由于现有Ni NPs的热催化作用，由g-CN生成了这些碳纳米管。我们的结果表明，优化的吡咯氮掺杂水平，再加上稳定的NCNT/Gr杂化结构、高电化学活性表面积、丰富的活性位点和减小的Ni NP尺寸，协同作用有助于实现卓越的电催化性能。所制备的Ni@NCNT/Gr-R催化剂在H型电池中表现出高的一氧化碳法拉第效率（>90%），在较宽的电位范围（-0.71--0.91 V vs RHE）内一氧化碳法拉第效率的差异可忽略不计，同时在-0.71 V（vs RHE）下保持了出色的稳定性，电流密度损失可忽略不计，持续24小时。我们的研究结果为在稳定的NCNT/Gr杂化基底内优化吡咯氮掺杂水平以及减小纳米颗粒尺寸以设计高效的一氧化碳还原催化剂提供了证据和见解。
