Synergistic electrocatalytic N2 reduction using a PTCA nanorod–rGO hybrid

Abstract

Currently, industrial-scale NH₃ production mainly relies on the energy-intensive and CO₂-emitting Haber–Bosch process from atmospheric N₂ and fossil fuels. Electrochemical N₂ fixation offers an eco-friendly and sustainable alternative to ambient NH₃ synthesis with the aid of efficient electrocatalysts for the N₂ reduction reaction (NRR). Here, a perylene-3,4,9,10-tetracarboxylic acid nanorod-reduced graphene oxide (PTCA–rGO) nanohybrid is proposed as a metal-free electrocatalyst to synergistically enhance N₂ reduction under ambient reaction conditions. In 0.1 M HCl, the PTCA–rGO hybrid provides a large NH₃ yield of 24.7 μg h⁻¹ mg_cat.⁻¹ and a high faradaic efficiency of 6.9% at −0.50 V vs. the reversible hydrogen electrode, which are much superior to those of PTCA and rGO counterparts. This catalyst also shows a high electrochemical and structural stability. Density functional theory calculations suggest that the NRR over the hybrid catalyst takes place via both distal associative and partially alternative routes.