Photochemical Acceleration of Ammonia Production by Pt1-Pt n-TiN Reduction and N2 Activation

Chengliang Mao; Jiaxian Wang; Yunjie Zou; Yanbiao Shi; Camilo J Viasus; Joel Y Y Loh; Meikun Xia; Shufang Ji; Meiqi Li; Huan Shang; Mireille Ghoussoub; Yang-Fan Xu; Jessica Ye; Zhilin Li; Nazir P Kherani; Lirong Zheng; Yanjiang Liu; Lizhi Zhang; Geoffrey A Ozin

doi:10.1021/jacs.3c01947

Photochemical Acceleration of Ammonia Production by Pt₁-Pt _n-TiN Reduction and N₂ Activation

J Am Chem Soc. 2023 Jun 21;145(24):13134-13146. doi: 10.1021/jacs.3c01947. Epub 2023 Jun 6.

Authors

Chengliang Mao^{1

2}, Jiaxian Wang³, Yunjie Zou¹, Yanbiao Shi³, Camilo J Viasus², Joel Y Y Loh⁴, Meikun Xia², Shufang Ji², Meiqi Li¹, Huan Shang¹, Mireille Ghoussoub², Yang-Fan Xu², Jessica Ye², Zhilin Li¹, Nazir P Kherani⁴, Lirong Zheng⁵, Yanjiang Liu⁶, Lizhi Zhang^{1

3}, Geoffrey A Ozin²

Affiliations

¹ Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China.
² Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
³ School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
⁴ Department of Materials Science and Engineering, University of Toronto, Toronto, Ontario M5S 3E4, Canada.
⁵ Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P. R. China.
⁶ Ontario Centre for the Characterization of Advanced Materials, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada.

PMID: 37278596
DOI: 10.1021/jacs.3c01947

Abstract

Stable metal nitrides (MN) are promising materials to fit the future "green" ammonia-hydrogen nexus. Either through catalysis or chemical looping, the reductive hydrogenation of MN to MN_1-x is a necessary step to generate ammonia. However, encumbered by the formation of kinetically stable M-NH_1─3 surface species, this reduction step remains challenging under mild conditions. Herein, we discovered that deleterious Ti-NH_1─3 accumulation on TiN can be circumvented photochemically with supported single atoms and clusters of platinum (Pt₁-Pt_n) under N₂-H₂ conditions. The photochemistry of TiN selectively promoted Ti-NH formation, while Pt₁-Pt_n effectively transformed any formed Ti-NH into free ammonia. The generated ammonia was found to originate mainly from TiN reduction with a minor contribution from N₂ activation. The knowledge accrued from this fundamental study could serve as a springboard for the development of MN materials for more efficient ammonia production to potentially disrupt the century-old fossil-powered Haber-Bosch process.