title: Highly active and stable hybrid catalyst of cobalt-doped FeS2 nanosheets-carbon nanotubes for hydrogen evolution reaction.
abstract: Hydrogen evolution reaction (HER) from water through electrocatalysis using cost-effective materials to replace precious Pt catalysts holds great promise for clean energy technologies. In this work we developed a highly active and stable catalyst containing Co doped earth abundant iron pyrite FeS(2) nanosheets hybridized with carbon nanotubes (Fe(1-x)CoxS(2)/CNT hybrid catalysts) for HER in acidic solutions. The pyrite phase of Fe(1-x)CoxS(2)/CNT was characterized by powder X-ray diffraction and absorption spectroscopy. Electrochemical measurements showed a low overpotential of ∼0.12 V at 20 mA/cm(2), small Tafel slope of ∼46 mV/decade, and long-term durability over 40 h of HER operation using bulk quantities of Fe(0.9)Co(0.1)S(2)/CNT hybrid catalysts at high loadings (∼7 mg/cm(2)). Density functional theory calculation revealed that the origin of high catalytic activity stemmed from a large reduction of the kinetic energy barrier of H atom adsorption on FeS(2) surface upon Co doping in the iron pyrite structure. It is also found that the high HER catalytic activity of Fe(0.9)Co(0.1)S(2) hinges on the hybridization with CNTs to impart strong heteroatomic interactions between CNT and Fe(0.9)Co(0.1)S(2). This work produces the most active HER catalyst based on iron pyrite, suggesting a scalable, low cost, and highly efficient catalyst for hydrogen generation.
authors.affiliation: Department of Chemistry, Stanford University , Stanford, California 94305, United States.
authors.forename: Di-Yan
authors.initials: DY
authors.lastname: Wang
authors.forename: Ming
authors.initials: M
authors.lastname: Gong
authors.forename: Hung-Lung
authors.initials: HL
authors.lastname: Chou
authors.forename: Chun-Jern
authors.initials: CJ
authors.lastname: Pan
authors.forename: Hsin-An
authors.initials: HA
authors.lastname: Chen
authors.forename: Yingpeng
authors.initials: Y
authors.lastname: Wu
authors.forename: Meng-Chang
authors.initials: MC
authors.lastname: Lin
authors.forename: Mingyun
authors.initials: M
authors.lastname: Guan
authors.forename: Jiang
authors.initials: J
authors.lastname: Yang
authors.forename: Chun-Wei
authors.initials: CW
authors.lastname: Chen
authors.forename: Yuh-Lin
authors.initials: YL
authors.lastname: Wang
authors.forename: Bing-Joe
authors.initials: BJ
authors.lastname: Hwang
authors.forename: Chia-Chun
authors.initials: CC
authors.lastname: Chen
authors.forename: Hongjie
authors.initials: H
authors.lastname: Dai