TY - JOUR
T1 - Controlling chemical reactions in confined environments
T2 - Water dissociation in MOF-74
AU - Fuentes-Fernandez, Erika M.A.
AU - Jensen, Stephanie
AU - Tan, Kui
AU - Zuluaga, Sebastian
AU - Wang, Hao
AU - Li, Jing
AU - Thonhauser, Timo
AU - Chabal, Yves J.
N1 - Funding Information:
Acknowledgments: This work was entirely supported by the Department of Energy Grant No. DE-FG02-08ER46491. T.T. also acknowledges generous support from the Simons Foundation through Grant No. 391888, which endowed his sabbatical leave at MIT.
Publisher Copyright:
© 2018 by the authors.
PY - 2018/2/12
Y1 - 2018/2/12
N2 - The confined porous environment of metal organic frameworks (MOFs) is an attractive system for studying reaction mechanisms. Compared to flat oxide surfaces, MOFs have the key advantage that they exhibit a well-defined structure and present significantly fewer challenges in experimental characterization. As an example of an important reaction, we study here the dissociation of water-which plays a critical role in biology, chemistry, and materials science-in MOFs and show how the knowledge of the structure in this confined environment allows for an unprecedented level of understanding and control. In particular, combining in-situ infrared spectroscopy and first-principles calculations, we show that the water dissociation reaction can be selectively controlled inside Zn-MOF-74 by alcohol, through both chemical and physical interactions. Methanol is observed to speed up water dissociation by 25% to 100%, depending on the alcohol partial pressure. On the other hand, co-adsorption of isopropanol reduces the speed of the water reaction, due mostly to steric interactions. In addition, we also investigate the stability of the product state after the water dissociation has occurred and find that the presence of additional water significantly stabilizes the dissociated state. Our results show that precise control of reactions within nano-porous materials is possible, opening the way for advances in fields ranging from catalysis to electrochemistry and sensors.
AB - The confined porous environment of metal organic frameworks (MOFs) is an attractive system for studying reaction mechanisms. Compared to flat oxide surfaces, MOFs have the key advantage that they exhibit a well-defined structure and present significantly fewer challenges in experimental characterization. As an example of an important reaction, we study here the dissociation of water-which plays a critical role in biology, chemistry, and materials science-in MOFs and show how the knowledge of the structure in this confined environment allows for an unprecedented level of understanding and control. In particular, combining in-situ infrared spectroscopy and first-principles calculations, we show that the water dissociation reaction can be selectively controlled inside Zn-MOF-74 by alcohol, through both chemical and physical interactions. Methanol is observed to speed up water dissociation by 25% to 100%, depending on the alcohol partial pressure. On the other hand, co-adsorption of isopropanol reduces the speed of the water reaction, due mostly to steric interactions. In addition, we also investigate the stability of the product state after the water dissociation has occurred and find that the presence of additional water significantly stabilizes the dissociated state. Our results show that precise control of reactions within nano-porous materials is possible, opening the way for advances in fields ranging from catalysis to electrochemistry and sensors.
KW - Confined environment
KW - Metal organic framework
KW - Reaction mechanism
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U2 - 10.3390/app8020270
DO - 10.3390/app8020270
M3 - Article
AN - SCOPUS:85042026342
VL - 8
JO - Applied Sciences (Switzerland)
JF - Applied Sciences (Switzerland)
SN - 2076-3417
IS - 2
M1 - 270
ER -