N-doped peanut-shaped carbon nanotubes for efficient CO2 electrocatalytic reduction

Using first principles calculations and the computational hydrogen electrode (CHE) model, we present the first systematic study of CO2 electrocatalytic reduction (CO2ER) on recently synthesized peanutshaped carbon nanotube (FP5N) as well as N-doped FP5N structures. We find FP5N to be metallic with the symmetry of D5h point group. In addition, nitrogen doping in FP5N significantly reduces the overpotential of CO2ER. In contrast to graphitic N that reduces CO2 into CO with an overpotential of 0.65 V, the pyrrolic N, octatomic N and pyridinic N in FP5N convert CO2 into CH3OH with even lower overpotentials of 0.52, 0.52 and 0.60 V, respectively. These values are comparable to those of industrial transition metal catalysts and show that N-doped peanut-shaped carbon nanotubes can outperform conventional N-doped carbon nanomaterials in CO2 reduction. (C) 2019 Published by Elsevier Ltd.