title: A Heterostructure Coupling of Exfoliated Ni-Fe Hydroxide Nanosheet and Defective Graphene as a Bifunctional Electrocatalyst for Overall Water Splitting.
abstract: Herein, the authors demonstrate a heterostructured NiFe LDH-NS@DG10 hybrid catalyst by coupling of exfoliated Ni-Fe layered double hydroxide (LDH) nanosheet (NS) and defective graphene (DG). The catalyst has exhibited extremely high electrocatalytic activity for oxygen evolution reaction (OER) in an alkaline solution with an overpotential of 0.21 V at a current density of 10 mA cm-2, which is comparable to the current record (≈0.20 V in Fe-Co-Ni metal-oxide-film system) and superior to all other non-noble metal catalysts. Also, it possesses outstanding kinetics (Tafel slope of 52 mV dec-1) for the reaction. Interestingly, the NiFe LDH-NS@DG10 hybrid has also exhibited the high hydrogen evolution reaction (HER) performance in an alkaline solution (with an overpotential of 115 mV by 2 mg cm-2loading at a current density of 20 mA cm-2) in contrast to barely HER activity for NiFe LDH-NS itself. As a result, the bifunctional catalyst the authors developed can achieve a current density of 20 mA cm-2by a voltage of only 1.5 V, which is also a record for the overall water splitting. Density functional theory calculation reveals that the synergetic effects of highly exposed 3d transition metal atoms and carbon defects are essential for the bifunctional activity for OER and HER.
authors.affiliation: Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan Campus, Queensland, 4111, Australia.|School of Natural Sciences, Griffith University, Queensland, 4111, Australia.
authors.forename: Yi
authors.initials: Y
authors.lastname: Jia
authors.affiliation: Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan Campus, Queensland, 4111, Australia.|School of Natural Sciences, Griffith University, Queensland, 4111, Australia.
authors.forename: Longzhou
authors.initials: L
authors.lastname: Zhang
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland, 4000, Australia.
authors.forename: Guoping
authors.initials: G
authors.lastname: Gao
authors.affiliation: School of Environmental and Chemical Engineering, Shanghai University, No. 99 Shangda Road, Shanghai, 200444, P. R. China.
authors.forename: Hua
authors.initials: H
authors.lastname: Chen
authors.affiliation: Environmental Futures Research Institute, Griffith University, Queensland, 4111, Australia.
authors.forename: Bei
authors.initials: B
authors.lastname: Wang
authors.affiliation: School of Environmental and Chemical Engineering, Shanghai University, No. 99 Shangda Road, Shanghai, 200444, P. R. China.|Materials Engineering, The University of Queensland, St. Lucia, Queensland, 4072, Australia.
authors.forename: Jizhi
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Materials Engineering, The University of Queensland, St. Lucia, Queensland, 4072, Australia.
authors.forename: Mun Teng
authors.initials: MT
authors.lastname: Soo
authors.affiliation: Materials Engineering, The University of Queensland, St. Lucia, Queensland, 4072, Australia.
authors.forename: Min
authors.initials: M
authors.lastname: Hong
authors.affiliation: Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan Campus, Queensland, 4111, Australia.|School of Natural Sciences, Griffith University, Queensland, 4111, Australia.
authors.forename: Xuecheng
authors.initials: X
authors.lastname: Yan
authors.affiliation: School of Environmental and Chemical Engineering, Shanghai University, No. 99 Shangda Road, Shanghai, 200444, P. R. China.
authors.forename: Guangren
authors.initials: G
authors.lastname: Qian
authors.affiliation: Materials Engineering, The University of Queensland, St. Lucia, Queensland, 4072, Australia.
authors.forename: Jin
authors.initials: J
authors.lastname: Zou
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland, 4000, Australia.
authors.forename: Aijun
authors.initials: A
authors.lastname: Du
authors.affiliation: Queensland Micro- and Nanotechnology Centre, Griffith University, Nathan Campus, Queensland, 4111, Australia.|School of Natural Sciences, Griffith University, Queensland, 4111, Australia.
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Yao
keywords: defects; graphene; heteroassembly; layered double hydroxide; nonprecious electrocatalysts