关键词: 形貌调节, 石墨烯片, 竹节碳纳米管, 电化学还原反应

Abstract:

Graphene nanosheets (GS) and carbon nanotubes have been considered as good catalysts candidates for applications in energy conversion and storage. However, hybrids of GS and carbon nanotubes are always formed in transition metal-based nitrogen-doped system, making the system quite complex for exploring the structure-activity relationship. To prepare the catalysts with desired species controllably, we try to adjust the outcomes with the effect of nitrogen on the growth of carbon nanotubes. In this work, a series of Fe-N co-doped carbon hybrid catalysts containing N-doped GS or hybrids of GS/bamboo carbon nanotubes (BCNTs) or BCNTs were obtained with one-step pyrolyzed method. To evaluate the effect of carbon morphology on performance of catalysts, oxygen reduction reaction (ORR) and CO₂ reduction reaction (CO₂RR) were used as model reactions. Electrochemical studies revealed that the catalysts containing only BCNTs showed the best performance of ORR (Eonset, 1.02 V_RHE) and CO2RR (FE_CO, 91.1% at -0.6 V_RHE) among the tested samples. Further investigations displayed that the remarkable activity is closely related to the defects, large specific surface area and high content of pyridinic N, and existence of FeN_x in the unique BCNTs. Such work deepens fundamental understanding in the morphology-dependent catalysis for both ORR and CO₂RR processes.

Key words: morphology tuning, graphene nanosheet, bamboo carbon nanotube, electrochemical reduction reaction