Unsaturated edge-anchored Ni single atoms on porous microwave exfoliated graphene oxide for electrochemical CO2

Supported single atom catalysts (SACs), emerging as a new class of catalytic materials, have been attracting increasing interests. Here we developed a Ni SAC on microwave exfoliated graphene oxide (Ni-N-MEGO) to achieve single atom loading of ∼6.9 wt%, significantly higher than previously reported SACs. The atomically dispersed Ni atoms, stabilized by coordination with nitrogen, were found to be predominantly anchored along the edges of nanopores (< 6 nm) using a combination of X-ray absorption spectroscopy (XAS) and aberration-corrected scanning transmission electron microscopy (AC-STEM). The Ni-N-MEGO exhibits an onset overpotential of 0.18 V, and a current density of 53.6 mA mg−1 at overpotential of 0.59 V for CO2 reduction reaction (CO2RR), representing one of the best non-precious metal SACs reported so far in the literature. Density functional theory (DFT) calculations suggest that the electrochemical CO2-to-CO conversion occurs more readily on the edge-anchored unsaturated nitrogen coordinated Ni single atoms that lead to enhanced activity toward CO2RR. © 2018 Elsevier B.V. All rights reserved.

Keywords

Nickel, Carbon dioxide, Graphene, Oxides, Electrochemistry, Atoms, Nitrogen, Spectroscopy

Citation

Cheng, Y., Zhao, S., Li, H., He, S., Veder, J.-P., Johannessen, B., Xiao, J., Lu, S., Pan, J., Chisholm, M. F., Yang, S.-Z., Liu, C., Chen, J. G., & Jiang, S. P. (2019). Unsaturated edge-anchored Ni single atoms on porous microwave exfoliated graphene oxide for electrochemical CO2. Applied Catalysis B: Environmental, 243, 294-303. doi:10.1016/j.apcatb.2018.10.046