The Challenge of Electrochemical Ammonia Synthesis: A New Perspective on the Role of Nitrogen Scaling Relations

Joseph H Montoya; Charlie Tsai; Aleksandra Vojvodic; Jens K Nørskov

doi:10.1002/cssc.201500322

The Challenge of Electrochemical Ammonia Synthesis: A New Perspective on the Role of Nitrogen Scaling Relations

ChemSusChem. 2015 Jul 8;8(13):2180-6. doi: 10.1002/cssc.201500322. Epub 2015 Jun 10.

Authors

Joseph H Montoya¹, Charlie Tsai², Aleksandra Vojvodic^{2

3}, Jens K Nørskov^{4

5}

Affiliations

¹ SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, CA 94305 (USA). [email protected].
² SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, CA 94305 (USA).
³ SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (USA).
⁴ SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, CA 94305 (USA). [email protected].
⁵ SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (USA). [email protected].

PMID: 26097211
DOI: 10.1002/cssc.201500322

Abstract

The electrochemical production of NH3 under ambient conditions represents an attractive prospect for sustainable agriculture, but electrocatalysts that selectively reduce N2 to NH3 remain elusive. In this work, we present insights from DFT calculations that describe limitations on the low-temperature electrocatalytic production of NH3 from N2 . In particular, we highlight the linear scaling relations of the adsorption energies of intermediates that can be used to model the overpotential requirements in this process. By using a two-variable description of the theoretical overpotential, we identify fundamental limitations on N2 reduction analogous to those present in processes such as oxygen evolution. Using these trends, we propose new strategies for catalyst design that may help guide the search for an electrocatalyst that can achieve selective N2 reduction.

Keywords: ammonia; catalyst design; density functional theory; electrocatalysis; transition metals.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Ammonia / chemical synthesis*
Electrochemical Techniques
Nitrogen / chemistry
Oxidation-Reduction
Transition Elements / chemistry

Substances

Transition Elements
Ammonia
Nitrogen