Deep eutectic solvent-assisted synthesis of oxygen vacancy-rich BaTiO3 as a support for Ru catalyst in ammonia synthesis at atmospheric pressure.

Ba-based perovskite oxides rich in oxygen vacancies (OVs) are anticipated to possess robust electron-donating capabilities and other favourable properties, rendering them a promising support for Ru catalysts in NH 3 synthesis. Herein, a glucose-urea deep eutectic solvent calcinating method was developed to synthesize an OV-rich BaTiO 3 (BTO-H) support for Ru catalysts. The BTO-H-supported Ru (Ru/BTO-H) catalyst achieves an impressive NH 3 synthesis rate of 5133 μmol g cat –1 h−1 (256.7 mmol g R u –1 h−1) at 400 °C and 0.1 MPa, surpassing the performance of Ru catalysts supported on OV-poor BTO supports and other supported Ru catalysts. Physical characterizations and kinetic experiments reveal the multifaceted influence of OVs on enhancing the catalytic performance of Ru/BTO-H in NH 3 synthesis. OVs serve as electron donors to Ru catalyst, facilitating the activation and dissociation of N 2. Simultaneously, OVs act as hydrogen acceptors from the Ru surface, mitigating hydrogen poisoning effects. Additionally, OVs stimulate the formation of surface hydrides, not only providing active sites for N 2 activation but also bestowing an electron-donating effect on the supported Ru catalyst. The combined positive effects of OVs establish BTO-H as an outstanding support for Ru catalysts in NH 3 synthesis. • A glucose-urea DES calcinating method was used to synthesize BaTiO 3 (BTO) support. • BTO support had rich oxygen vacancies and large specific surface area (70 m2 g−1). • Oxygen vacancies in BTO support played multiple roles in NH 3 synthesis. • BTO-supported Ru catalyst exhibited an NH 3 synthesis rate of 5133 μmol g-1 cat h−1. [ABSTRACT FROM AUTHOR]