TY - JOUR
T1 - Molybdenum sulfide within a metal-organic framework for photocatalytic hydrogen evolution from water
AU - Noh, Hyunho
AU - Yang, Ying
AU - Ahn, Sol
AU - Peters, Aaron W.
AU - Farha, Omar K.
AU - Hupp, Joseph T.
N1 - Funding Information:
This work was supported as part of the Center for Light Energy Activated Redox Processes (LEAP), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0001059. H.N. gratefully acknowledges support from the Ryan Fellowship program of the North-western University International Institute of Nanotechnology. H.N. acknowledges Rebecca Palmer for her help in conducting dynamic light scattering experiment. This work made use of the J. B. Cohen X-ray Diffraction, EPIC, and KECK II facilities of Northwestern University’s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR1720139) at the Materials Research Center; the Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. Finally, we thank UT Arlington Distinguished University Professor Raj Rajeshwar for his service to ECS and the photoelectrochemistry community, and to congratulate him on an extraordinary body of research accomplishments over the course of his first seventy years.
PY - 2019
Y1 - 2019
N2 - A representative metal-organic framework, NU-1000, was functionalized with MoSx. The previously determined crystal structure of the material, named MoSx-SIM, consists of monometallic Mo(IV) ions with two sulfhydryl ligands. The metal ions are anchored to the framework by displacing protons presented by the-OH/-OH2 groups on the Zr6 node. As shown previously, the MOF-supported complexes are electrocatalytic for hydrogen evolution from acidified water. The earlier electrocatalysis results, together with the nearly ideal formal potential of the Mo(IV/II) couple (i.e., nearly coincident with that of the hydrogen couple), and the physical proximity of UV-absorbing MOF linkers to the complexes, suggested to us that the linkers might behave photosensitizers for catalyst reduction, and subsequently, for H2 evolution from water. To our surprise, MoSx-SIM, when UV-illuminated in an aqueous buffer at near-neutral pH, displays a biphasic photocatalytic response: an initially slow rate of reaction, i.e. 0.56 mmol g-1 h-1, followed by an increase to 4 mmol g-1 h-1. Ex-situ catalyst examination revealed that nanoparticulate MoSx suspended within the reaction mixture is the actual catalyst. Thus, photo-assisted restructuring and detachment of the catalyst or pre-catalyst from the MOF node appears to be necessary for the catalyst to reduce water at neutral pH.
AB - A representative metal-organic framework, NU-1000, was functionalized with MoSx. The previously determined crystal structure of the material, named MoSx-SIM, consists of monometallic Mo(IV) ions with two sulfhydryl ligands. The metal ions are anchored to the framework by displacing protons presented by the-OH/-OH2 groups on the Zr6 node. As shown previously, the MOF-supported complexes are electrocatalytic for hydrogen evolution from acidified water. The earlier electrocatalysis results, together with the nearly ideal formal potential of the Mo(IV/II) couple (i.e., nearly coincident with that of the hydrogen couple), and the physical proximity of UV-absorbing MOF linkers to the complexes, suggested to us that the linkers might behave photosensitizers for catalyst reduction, and subsequently, for H2 evolution from water. To our surprise, MoSx-SIM, when UV-illuminated in an aqueous buffer at near-neutral pH, displays a biphasic photocatalytic response: an initially slow rate of reaction, i.e. 0.56 mmol g-1 h-1, followed by an increase to 4 mmol g-1 h-1. Ex-situ catalyst examination revealed that nanoparticulate MoSx suspended within the reaction mixture is the actual catalyst. Thus, photo-assisted restructuring and detachment of the catalyst or pre-catalyst from the MOF node appears to be necessary for the catalyst to reduce water at neutral pH.
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U2 - 10.1149/2.0261905jes
DO - 10.1149/2.0261905jes
M3 - Article
AN - SCOPUS:85063162956
VL - 166
SP - H3154-H3158
JO - Journal of the Electrochemical Society
JF - Journal of the Electrochemical Society
SN - 0013-4651
IS - 5
ER -