PdP2 nanoparticles–reduced graphene oxide for electrocatalytic N2 conversion to NH3 under ambient conditions

Abstract

Producing NH₃ through the Haber–Bosch process has brought about huge energy-consumption and heavy emission of CO₂. Electrochemical N₂ reduction offers a promising alternative to realize N₂ fixation under ambient conditions. In this paper, PdP₂ nanoparticles–reduced graphene oxide (PdP₂–rGO) is proposed as an efficient electrocatalyst for the N₂ reduction reaction. In 0.5 M LiClO₄, PdP₂–rGO affords a large NH₃ yield rate of 30.3 μg h⁻¹ mg_cat.⁻¹ and a high faradaic efficiency of 12.56% at −0.1 V versus the reversible hydrogen electrode, which are much superior to those of its Pd–rGO counterpart (NH₃ yield rate of 14.5 μg h⁻¹ mg_cat.⁻¹ and FE of 4.28%). This catalyst also shows high stability. Density functional theory calculations suggest that the barriers for N₂ activation and the subsequent hydrogenation process on the Pd catalyst are alleviated after alloying with P.