Electrochemical reduction of nitrate (NO3RR) offers an attractive route for ammonia synthesis and simultaneously alleviates environmental concerns for nitrate pollution. A critical step for large-scale implementation of this technology is the development of catalyst materials that exhibit high catalytic activity for NO3RR to ammonia. Transition metals have been widely studied as potential catalyst materials for this reaction. Herein, we investigate the underlying reaction mechanisms of the NO3RR over different transition metal catalysts by calculating the binding energies of various reaction intermediates via Density Functional Theory (DFT). Using the linear scaling relations between NO3RR intermediates, we construct activity volcano plots by using the binding energies of *NO and *OH adsorbates as descriptors to describe the trends in NO3RR catalytic activity for different transition metals. This study reveals that the protonation of adsorbed NO or adsorbed NO3 are bottleneck steps causing the overpotential for NO3RR to ammonia suggesting two possible approaches for designing catalyst materials with reduced overpotential by tuning the binding energies of *NO and *OH. In addition, enhanced catalytic selectivity by suppressing the competing hydrogen evolution reaction was considered. Ultimately, this study suggests possible strategies to identify catalyst materials with improved catalytic activity and selectivity for NO3RR.
Audience take away:
- Explain how the audience will be able to use what they learn? This presentation provides a guideline for identifying efficient materials for reduction of nitrate to ammonia.
- How will this help the audience in their job? -
- Is this research that other faculty could use to expand their research or teaching? Yes, it provides a new research direction for catalyst design.
- Does this provide a practical solution to a problem that could simplify or make a designer’s job more efficient?
- Will it improve the accuracy of a design, or provide new information to assist in a design problem? Yes
- List all other benefits.