Breaking the Volcano-Shaped Relationship for Highly Efficient Electrocatalytic Nitrogen Reduction: A Computational Guideline

Abstract

The volcano-shaped relationship is very common in electrocatalytic nitrogen reduction reaction (e-NRR) and is usually caused by the competition between the first and last hydrogenation steps. How to break such a relationship to further improve the catalytic performance remains a great challenge. Herein, using first-principles calculations, we investigate a range of transition-metal (TM)-doped Cu-based single-atom alloys (TM 1 -Cu( 111)) as catalysts for e-NRR. When the adsorption of N 2 on the catalysts is strong enough, the inert N 2 molecules can be effectively activated for the first hydrogenation step. Meanwhile, the last hydrogenation step is not affected by the scaling relationship and remains easy on all of the catalysts due to the unstable top-site adsorption of NH 2 , resulting in the break of the volcano-shaped relationship in e-NRR. Thus, only the first hydrogenation step is identified as the potential determining step. Four TM 1 -Cu(111) catalysts (TM = Re, W, Tc, and Mo) are selected as promising catalysts with limiting potential ranging from −0.38 to −0.56 V, showing outstanding e-NRR activity. Besides, the four catalysts also inhibit the competing hydrogen evolution reaction and long-term stability. Our work provides a guideline for breaking the volcanoshaped relationship in e-NRR and significant in the rational design of highly efficient electrocatalysts.

Theoretical insight into the essential role of charged surface for ammonia synthesis: Si-decorated carbon nitride electrode

“…In numerous previous studies, 1,4,7,10,14,19,37–41 DFT calculations have perfectly predicted and explained many physicochemical changes in the laboratory. Nevertheless, most of these existing works can only present relative variation trends, and few direct criteria can be given.…”

Direct Electrochemical Synthesis of Acetamide from CO2 and N2 on a Single-Atom Alloy Catalyst

“…By the literature reports, , we have observed that N 2 predominantly adopts an end-on configuration on most TM/Cu(111) SAA surfaces, except for groups IB and IIB metals where N 2 undergoes physical adsorption similar to Cu(111) (Figure S5). For N 2 molecules, physisorption gives a N–N bond length of 1.11 Å, similar to that of gaseous N 2 (1.10 Å), while chemisorption results in noticeable elongation and partial activation of the N–N bond (Figure S6).…”

“…By prior investigations on NRR catalyzed by SAA catalysts, we have discovered that N 2 reduction proceeds through the associative mechanism due to its end-on adsorption configuration on W/Cu(111). ,− *N 2 reduction undergoes three hydrogenation steps to generate *N and NH 3 , among which the initial hydrogenation step (*N 2 + H + + e – → *N 2 H) proves to be the most challenging with a Δ G of 0.39 eV. The generated NH 3 then undergoes C–N coupling with *CCO to form *CC­(OH)­NH 2 (Δ G = −0.03 eV).…”

“…5,22,30 Moreover, Gao et al demonstrated that TM 1 -Cu(111) catalysts (TM = Re, W, Tc, and Mo) are exceptional electrocatalysts for the nitrogen reduction reaction (NRR), producing ammonia via a distal associative pathway with remarkable efficiency. 31 Jouny et al demonstrated the formation of C−N bonds using an amine nucleophilic attack on a surface-bound ketene intermediate on Cu catalysts, resulting in the generation of diverse amide products. 10 Therefore, Cu-based catalysts possess a remarkable ability to catalyze NRR, C−C, and C−N coupling reactions simultaneously, making them highly promising for the electrocatalytic synthesis of acetamide from CO 2 and N 2 .…”

“…Copper, a common and inexpensive material, is one of the most promising electrocatalysts for transforming CO 2 /CO to C 2 products. − The introduction of heteroatoms into Cu to form Cu-based single-atom alloy (SAA) catalysts has been demonstrated as an effective method for tuning catalytic activity and controlling product distribution in CRR. , Experimentally, a plethora of single-atom alloys have been successfully synthesized, including but not limited to Pt, , Pd, Ru, , Au, and Ti . These materials exhibit superior activity compared to Cu(111) in carbon dioxide reduction reactions and C–C coupling processes. ,, Moreover, Gao et al demonstrated that TM 1 -Cu­(111) catalysts (TM = Re, W, Tc, and Mo) are exceptional electrocatalysts for the nitrogen reduction reaction (NRR), producing ammonia via a distal associative pathway with remarkable efficiency . Jouny et al demonstrated the formation of C–N bonds using an amine nucleophilic attack on a surface-bound ketene intermediate on Cu catalysts, resulting in the generation of diverse amide products .…”