title: Design of active and stable Co-Mo-Sx chalcogels as pH-universal catalysts for the hydrogen evolution reaction.
abstract: Three of the fundamental catalytic limitations that have plagued the electrochemical production of hydrogen for decades still remain: low efficiency, short lifetime of catalysts and a lack of low-cost materials. Here, we address these three challenges by establishing and exploring an intimate functional link between the reactivity and stability of crystalline (CoS2 and MoS2) and amorphous (CoSx and MoSx) hydrogen evolution catalysts. We propose that Co(2+) and Mo(4+) centres promote the initial discharge of water (alkaline solutions) or hydronium ions (acid solutions). We establish that although CoSx materials are more active than MoSx they are also less stable, suggesting that the active sites are defects formed after dissolution of Co and Mo cations. By combining the higher activity of CoSx building blocks with the higher stability of MoSx units into a compact and robust CoMoSx chalcogel structure, we are able to design a low-cost alternative to noble metal catalysts for efficient electrocatalytic production of hydrogen in both alkaline and acidic environments.
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Jakub
authors.initials: J
authors.lastname: Staszak-Jirkovský
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.|Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Christos D
authors.identifier: http://orcid.org/0000-0003-4416-638X
authors.initials: CD
authors.lastname: Malliakas
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Pietro P
authors.initials: PP
authors.lastname: Lopes
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Nemanja
authors.initials: N
authors.lastname: Danilovic
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Subrahmanyam S
authors.initials: SS
authors.lastname: Kota
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Kee-Chul
authors.initials: KC
authors.lastname: Chang
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.|University of Ljubljana, Ljubljana 1000, Slovenia.
authors.forename: Bostjan
authors.identifier: http://orcid.org/0000-0002-0714-3472
authors.initials: B
authors.lastname: Genorio
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Dusan
authors.initials: D
authors.lastname: Strmcnik
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Vojislav R
authors.initials: VR
authors.lastname: Stamenkovic
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.|Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Mercouri G
authors.initials: MG
authors.lastname: Kanatzidis
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Nenad M
authors.initials: NM
authors.lastname: Markovic