TiO2 nanoparticles–reduced graphene oxide hybrid: an efficient and durable electrocatalyst toward artificial N2 fixation to NH3 under ambient conditions

Abstract

The Haber–Bosch process enables the industrial production of NH₃ from N₂ and H₂, but it has problems with high energy consumption and CO₂ emissions. Electrochemical reduction offers an environmentally-benign and sustainable alternative for NH₃ synthesis. In this communication, we describe a TiO₂ nanoparticles–reduced graphene oxide hybrid (TiO₂–rGO) which behaves as an efficient non-noble-metal N₂ reduction reaction (NRR) electrocatalyst for N₂-to-NH₃ conversion with excellent selectivity. When tested in 0.1 M Na₂SO₄, the TiO₂–rGO achieves a high faradaic efficiency of 3.3% and a large NH₃ yield of 15.13 μg h⁻¹ mg_cat.⁻¹ at −0.90 V vs. a reversible hydrogen electrode. Notably, this catalyst also shows high electrochemical stability during electrolysis and recycling tests.