The development of low‐cost and efficient electrocatalysts for nitrogen reduction reaction (NRR) at ambient conditions is crucial for NH3synthesis and provides an alternative to the traditional Harber‐Bosch process. Herein, by means of density functional theory (DFT) computations, the catalytic performance of a series of single metal atoms supported on graphitic carbon nitride (g‐C3N4) for NRR is evaluated. Among all the candidates, the Gibbs free energy change of the potential‐determining step for five single‐atom catalysts (SACs), namely Ti, Co, Mo, W, and Pt atoms supported on g‐C3N4monolayer, is lower than that on the Ru(0001) stepped surface. In particular, the single tungsten (W) atom anchored on g‐C3N4(W@g‐C3N4) exhibits the highest catalytic activity toward NRR with a limiting potential of −0.35 V via associative enzymatic pathway, and can well suppress the competing hydrogen evolution reaction. The high NRR activity and selectivity of W@g‐C3N4are attributed to its inherent properties, such as significant positive charge and large spin moment on the W atom, excellent electrical conductivity, and moderate adsorption strength with NRR intermediates. This work opens up a new avenue of N2reduction for renewable energy supplies and helps guide future development of single‐atom catalysts for NRR and other related electrochemical process.
Direct conversion of CO2into carbon‐neutral fuels or industrial chemicals holds a great promise for renewable energy storage and mitigation of greenhouse gas emission. However, experimentally finding an electrocatalyst for specific final products with high efficiency and high selectivity poses serious challenges due to multiple electron transfer, complicated intermediates, and numerous reaction pathways in electrocatalytic CO2reduction. Here, an intrinsic descriptor that correlates the catalytic activity with the topological, bonding, and electronic structures of catalytic centers on M–N–C based single‐atom catalysts is discovered. The “volcano”‐shaped relationships between the descriptor and catalytic activity are established from which the best single‐atom catalysts for CO2reduction are found. Moreover, the reaction mechanisms, intermediates, reaction pathways, and final products can also be distinguished by this new descriptor. The descriptor can also be used to predict the activity of the single‐atom catalysts for electrochemical reactions such as hydrogen evolution, oxygen reduction and evolution reactions in fuel cells and water‐splitting. These predictions are confirmed by the experimental results for onset potential and Faraday efficiency. The design principles derived from the descriptors open a door for rational design and rapid screening of highly efficient electrocatalysts for CO2conversion as well as other electrochemical energy systems.
more » « less- NSF-PAR ID:
- 10457795
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Energy Materials
- Volume:
- 9
- Issue:
- 44
- ISSN:
- 1614-6832
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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