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Atmospheric nitrogen fixation using a photocatalytic system is a promising approach to produce ammonia. However, most of the recently explored photocatalysts for N 2 fixation are in the powder form, suffering from agglomeration and difficulty in the collection and leading to unsatisfactory conversion efficiency. Developing efficient film catalysts for N 2 photofixation under ambient conditions remains challenging. Herein, we report the efficient photofixation of N 2 over a periodic WS 2 @TiO 2 nanoporous film, which is fabricated through a facile method that combines anodization, E-beam evaporation, and chemical vapor deposition (CVD). Oxygen vacancies are introduced into TiO 2 nanoporous films through Ar annealing treatment, which plays a vital role in N 2 adsorption and activation. The periodic WS 2 @TiO 2 nanoporous film with an optimized WS 2 content shows highly efficient photocatalytic performance for N 2 fixation with an NH 3 evolution rate of 1.39 mmol g −1 h −1 , representing one of the state-of-the-art catalysts.
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Screening and Discovery of Metal Compound Active Sites for Strong and Selective Adsorption of N 2 in Air
Abstract Photocatalytic nitrogen fixation has the potential to provide a greener route for producing nitrogen‐based fertilizers under ambient conditions. Computational screening is a promising route to discover new materials for the nitrogen fixation process, but requires identifying “descriptors” that can be efficiently computed. In this work, we argue that selectivity toward the adsorption of molecular nitrogen and oxygen can act as a key descriptor. A catalyst that can selectively adsorb nitrogen and resist poisoning of oxygen and other molecules present in air has the potential to facilitate the nitrogen fixation process under ambient conditions. We provide a framework for active site screening based on multifidelity density functional theory (DFT) calculations for a range of metal oxides, oxyborides, and oxyphosphides. The screening methodology consists of initial low‐fidelity fixed geometry calculations and a second screening in which more expensive geometry optimizations were performed. The approach identifies promising active sites on several TiO2polymorph surfaces and a VBO4surface, and the full nitrogen reduction pathway is studied with the BEEF‐vdW and HSE06 functionals on two active sites. The findings suggest that metastable TiO2polymorphs may play a role in photocatalytic nitrogen fixation, and that VBO4may be an interesting material for further studies.
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- Award ID(s):
- 1943707
- PAR ID:
- 10476063
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemSusChem
- Volume:
- 16
- Issue:
- 22
- ISSN:
- 1864-5631
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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