Hydrogen Spillover to Oxygen Vacancy of TiO2- xHy/Fe: Breaking the Scaling Relationship of Ammonia Synthesis

Chengliang Mao; Jiaxian Wang; Yunjie Zou; Guodong Qi; Joel Yi Yang Loh; Tianhua Zhang; Meikun Xia; Jun Xu; Feng Deng; Mireille Ghoussoub; Nazir P Kherani; Lu Wang; Huan Shang; Meiqi Li; Jie Li; Xiao Liu; Zhihui Ai; Geoffrey A Ozin; Jincai Zhao; Lizhi Zhang

doi:10.1021/jacs.0c06118

Hydrogen Spillover to Oxygen Vacancy of TiO_{2- x}H_y/Fe: Breaking the Scaling Relationship of Ammonia Synthesis

J Am Chem Soc. 2020 Oct 14;142(41):17403-17412. doi: 10.1021/jacs.0c06118. Epub 2020 Oct 5.

Authors

Chengliang Mao^{1

2}, Jiaxian Wang¹, Yunjie Zou¹, Guodong Qi³, Joel Yi Yang Loh⁴, Tianhua Zhang⁵, Meikun Xia², Jun Xu³, Feng Deng³, Mireille Ghoussoub², Nazir P Kherani⁴, Lu Wang², Huan Shang¹, Meiqi Li¹, Jie Li¹, Xiao Liu¹, Zhihui Ai¹, Geoffrey A Ozin², Jincai Zhao¹, Lizhi Zhang¹

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, Departments of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada.
³ State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Innovation Academy for Precision Measurement Science and Technology, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, P. R. China.
⁴ Department of Materials Science and Engineering, University of Toronto, 184 College Street, Suite 140, Toronto, Ontario M5S 3E4, Canada.
⁵ National Engineering Research Center of Chemical Fertilizer Catalyst (NERC-CFC), School of Chemical Engineering, Fuzhou University, Fuzhou, Fujian 350002, P. R. China.

PMID: 32948092
DOI: 10.1021/jacs.0c06118

Abstract

Optimizing kinetic barriers of ammonia synthesis to reduce the energy intensity has recently attracted significant research interest. The motivation for the research is to discover means by which activation barriers of N₂ dissociation and NH_z (z = 1-2, surface intermediates) destabilization can be reduced simultaneously, that is, breaking the "scaling relationship". However, by far only a single success has been reported in 2016 based on the discovery of a strong-weak N-bonding pair: transition metals (nitrides)-LiH. Described herein is a second example that is counterintuitively founded upon a strong-strong N-bonding pair unveiled in a bifunctional nanoscale catalyst TiO_2-xH_y/Fe (where 0.02 ≤ x ≤ 0.03 and 0 < y < 0.03), in which hydrogen spillover (H) from Fe to cascade oxygen vacancies (O_V-O_V) results in the trapped form of O_V-H on the TiO_2-xH_y component. The Fe component thus enables facile activation of N₂, while the O_V-H in TiO_2-xH_y hydrogenates the N or NH_z to NH₃ easily.