Zhang Shilei, Yue Pengtao, Zhou Yue, Li Jun, Zhu Xun, Fu Qian, Liao Qiang
Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University, Ministry of Education, Chongqing, 400044, China.
Institute of Engineering Thermophysics, School of Energy and Power Engineering, Chongqing University, Chongqing, 400044, China.
Small. 2023 Oct;19(43):e2303016. doi: 10.1002/smll.202303016. Epub 2023 Jun 27.
Ni single-atom catalysts (SACs) are appealing for electrochemical reduction CO reduction (CO RR). However, regulating the balance between the activity and conductivity remains a challenge to Ni SACs due to the limitation of substrates structure. Herein, the intrinsic performance enhancement of Ni SACs anchored on quasi-one-dimensional graphene nanoribbons (GNRs) synthesized is demonstrated by longitudinal unzipping carbon nanotubes (CNTs). The abundant functional groups on GNRs can absorb Ni atoms to form rich Ni-N -C sites during the anchoring process, providing a high intrinsic activity. In addition, the GNRs, which maintain a quasi-one-dimensional structure and possess a high conductivity, interconnect with each other and form a conductive porous framework. The catalyst yields a 44 mA cm CO partial current density and 96% faradaic efficiency of CO (FE ) at -1.1 V vs RHE in an H-cell. By adopting a membrane electrode assembly (MEA) flow cell, a 95% FE and 2.4 V cell voltage are achieved at 200 mA cm current density. This work provides a rational way to synthesize Ni SACs with a high Ni atom loading, porous morphology, and high conductivity with potential industrial applications.
镍单原子催化剂（SACs）在电化学还原一氧化碳（CO RR）方面具有吸引力。然而，由于基底结构的限制，调节镍单原子催化剂的活性和导电性之间的平衡仍然是一个挑战。在此，通过纵向解开碳纳米管（CNTs），证明了锚定在合成的准一维石墨烯纳米带（GNRs）上的镍单原子催化剂的本征性能增强。在锚定过程中，GNRs上丰富的官能团可以吸收镍原子形成丰富的Ni-N-C位点，提供高本征活性。此外，保持准一维结构并具有高导电性的GNRs相互连接，形成导电多孔框架。在H型电解池中，该催化剂在相对于可逆氢电极（RHE）为-1.1 V时，产生44 mA cm的CO分电流密度和96%的CO法拉第效率（FE）。通过采用膜电极组件（MEA）流动电解池，在200 mA cm的电流密度下实现了95%的FE和2.4 V的电池电压。这项工作提供了一种合理的方法来合成具有高镍原子负载、多孔形态和高导电性的镍单原子催化剂，具有潜在的工业应用价值。
