Heterostructuring 2D TiO2 nanosheets in situ grown on Ti3C2Tx MXene to improve the electrocatalytic nitrogen reduction

In this study, TiO2 nanosheets (NSs) grown in situ on extremely conductive Ti3C2Tx MXene to form TiO2/Ti3C2Tx MXene composites with abundant active sites are proposed to effectively achieve electrocatalytic NH3 synthesis. Electron transfer can be promoted by Ti3C2Tx MXene with high conductivity. Meanwhile, the TiO2 NSs in-situ formation can not only avoid Ti3C2Tx MXene microstacking but also enhance the surface specific area of Ti3C2Tx MXene. The TiO2/Ti3C2Tx MXene catalyst reaches a high Faradaic efficiency (FE) of 44.68% at −0.75 V vs. RHE and a large NH3 yield of 44.17 µg h−1 mg−1cat. at −0.95 V, with strong electrochemical durability. 15N isotopic labeling experiments imply that the N in the produced NH3 originated from the N2 of the electrolyte. DFT calculations were conducted to determine the possible NRR reaction pathways for TiO2/Ti3C2Tx MXene composites. MXene catalysts combined with other materials have been rationally designed for efficient ammonia production under ambient conditions. © 2022 Dalian Institute of Chemical Physics, the Chinese Academy of Sciences