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Tackling the Activity and Selectivity Challenges of Electrocatalysts toward the Nitrogen Reduction Reaction via Atomically Dispersed Biatom Catalysts
journal contribution
posted on 2020-03-16, 13:40 authored by Xiangyu Guo, Jinxing Gu, Shiru Lin, Shengli Zhang, Zhongfang Chen, Shiping HuangDeveloping
efficient catalysts for nitrogen fixation is becoming
increasingly important but is still challenging due to the lack of
robust design criteria for tackling the activity and selectivity problems,
especially for electrochemical nitrogen reduction reaction (NRR).
Herein, by means of large-scale density functional theory (DFT) computations,
we reported a descriptor-based design principle to explore the large
composition space of two-dimensional (2D) biatom catalysts (BACs),
namely, metal dimers supported on 2D expanded phthalocyanine (M2-Pc or MM′-Pc), toward the NRR at the acid conditions.
We sampled both homonuclear (M2-Pc) and heteronuclear (MM′-Pc)
BACs and constructed the activity map of BACs by using N2H* adsorption energy as the activity descriptor, which reduces the
number of promising catalyst candidates from over 900 to less than
100. This strategy allowed us to readily identify 3 homonuclear and
28 heteronuclear BACs, which could break the metal-based activity
benchmark toward the efficient NRR. Particularly, using the free energy
difference of H* and N2H* as a selectivity descriptor,
we screened out five systems, including Ti2-Pc, V2-Pc, TiV-Pc, VCr-Pc, and VTa-Pc, which exhibit a strong capability
of suppressing the competitive hydrogen evolution reaction (HER) with
favorable limiting potential of −0.75, −0.39, −0.74,
−0.85, and −0.47 V, respectively. This work not only
broadens the possibility of discovering more efficient BACs toward
N2 fixation but also provides a feasible strategy for rational
design of NRR electrocatalysts and helps pave the way to fast screening
and design of efficient BACs for the NRR and other electrochemical
reactions.