Tuning electrocatalytic nitrogen reduction on supported nickel cluster via substrate phase engineering

Abstract

Metal clusters supported on the substrate is promising nitrogen reduction reaction (NRR) electrocatalysts due to their diversity and tunable sizes. However, how to rationally select clusters depending on substrates to promote NRR performance is not elucidated yet. To address this problem, we systematically investigate the NRR activity of Nin (n = 4, 13) clusters anchored on H and T′-phases WTe2 substrates, which offer ‘uniform’ and ‘nonuniform’ surfaces, respectively. Based on density functional theory calculations, we find that Ni4@H-WTe2 exhibits the highest NRR activity with an ultralow overpotential of 0.24 V, which is superior to that of Ni13@H-WTe2. While for the T′ phase WTe2, a larger cluster Ni13@T′-WTe2 is preferred. These differences arise from the distorted interaction between clusters and H and T′-WTe2 surfaces. The ‘uniform surface’ possessing one type of Te atom tends to deform small clusters severely, while the ‘nonuniform surface’ offers a buckling surface that deforms large Ni13 sufficiently. With the phases engineered deformation of Nin, the NRR performance is modulated. Our work highlights a strategy to design efficient NRR electrocatalysts via matching substrate phase and cluster size.