Significance
Industrial NH3 production is overreliance on the Haber–Bosch technology, which requires harsh operating conditions with 1 to 2% of the world’s energy supply and vast CO2 emissions. Electrocatalytic synthesis of NH3 via the N2 reduction reaction (ENRR) is an eminently attractive technology using renewable energy, while the present efficiency achieved is fairly low. Currently, the simultaneous achievement of high selectivity and yield of NH3 is severely prevented due to the lack of close cooperation of the electrocatalyst and electrolyzer. Herein, a structurally controlled catalyst is applied into a pressurized reactor, which breaks the thermodynamic and kinetic limits, achieving a high selectivity and yield of NH3. This work boosts an advancement of materials and engineering for ENRR toward practical application.
Abstract
Electrochemical conversion of N2 into ammonia presents a sustainable pathway to produce hydrogen storage carrier but yet requires further advancement in lectrocatalyst design and electrolyzer integration. This technology suffers from low selectivity and yield owing to the extremely strong N≡N bond and the exceptionally low solubility of N2 in aqueous systems. A high NH3 synthesis performance is restricted by the high activation energy of N≡N bond and the supply insufficiency of N2 to active sites. This paper describes the introduction of electron-rich Bi0 sites into Ag catalysts with a high-pressure electrolyzer that enables a dramatically enhanced Faradaic efficiency of 44.0% and yield of 28.43 μg cm−2 h−1 at 4.0 MPa. Combined with density functional theory results, in situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy demonstrates that N2 reduction reaction follows an associative mechanism, in which a high coverage of N–N bond and −NH2 intermediates suggest electron-rich Bi0 boosts sound activation of N2 molecules and low hydrogenation barrier. The proposed strategy of engineering electrochemical cataysts and devices provides powerful guidelines for achieving industrial-level green ammonia production.
Continue Reading
Data, Materials, and Software Availability
All study data are included in the article and/or SI Appendix.
Acknowledgments
We acknowledge the National Natural Science Foundation of China (22121004, 51861125104), Haihe Laboratory of Sustainable Chemical Transformations, the Program of Introducing Talents of Discipline to Universities (No. BP0618007) and the Xplorer Prize for financial support.
Author contributionsT.W. and J.G. supervised and designed research; Y.W., X.L., G.Z., and H.G. performed research; Y.W., T.W. and J.G. contributed new reagents/analytic tools; Y.W., X.L., Z.-J.Z., T.W., and J.G. analyzed data; and all authors wrote the paper.
Competing interestsThe authors declare no competing interest.
Supporting Information