Tuning N2 activation pathway over Ru/Co sub-nanometer alloy for efficient ammonia synthesis

The desire of green ammonia (NH3) production requires efficient catalysts that could operate at mild conditions. However, the activity of catalysts is restricted by scaling relation that low activation energy of N-2 is in conjunction with the over-strong affinity of intermediates, which blocks adsorption sites of catalyst and hinders NH3 production. Single atom alloy (SAA) is an efficient approach to circumvent this relation. In the present work, we offer a feasible strategy of preparing M1Ru (M = Fe, Co, Ni) SAA. Our studies show that Co1Ru SAA has the highest NH3 synthesis rate and the largest TOFRu value among M1Ru SAA. Compared with CoRu nanoparticle alloy (NPA), Co1Ru SAA has stronger electronic interaction between Co and Ru, which induces lower work function and up-shift d band center toward Fermi level for Co1Ru SAA, thus promoting N-2 activation. Meanwhile, the unique SAA structure could effectively tune N-2 activation pathway. Those findings make a contribution to the development of advanced catalysts for efficient NH3 synthesis at mild conditions. (C) 2021 Elsevier Inc. All rights reserved.