TiO2 nanoparticles-reduced graphene oxide hybrid: an efficient and durable electrocatalyst toward artificial N-2 fixation to NH3 under ambient conditions

The Haber-Bosch process enables the industrial production of NH3 from N-2 and H-2, 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 N-2 reduction reaction (NRR) electrocatalyst for N-2-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 mu g 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.