title: A hierarchically porous nickel-copper phosphide nano-foam for efficient electrochemical splitting of water.
abstract: Electrochemical splitting of water to produce oxygen (O2) and hydrogen (H2) through a cathodic hydrogen evolution reaction (HER) and an anodic oxygen evolution reaction (OER) is a promising green approach for sustainable energy supply. Here we demonstrated a porous nickel-copper phosphide (NiCuP) nano-foam as a bifunctional electrocatalyst for highly efficient total water splitting. Prepared from a bubble-templated electrodeposition method and subsequent low-temperature phosphidization, NiCuP has a hierarchical pore structure with a large electrochemical active surface area. To reach a high current density of 50 mA cm-2, it requires merely 146 and 300 mV with small Tafel slopes of 47 and 49 mV dec-1for HER and OER, respectively. The total water splitting test using NiCuP as both the anode and cathode showed nearly 100% Faradic efficiency and surpassed the performances of electrode pairs using commercial Pt/C and IrO2catalysts under our test conditions. The high activity of NiCuP can be attributed to (1) the conductive NiCu substrates, (2) a large electrochemically active surface area together with a combination of pores of different sizes, and (3) the formation of active Ni/Cu oxides/hydroxides while keeping a portion of more conductive Ni/Cu phosphides in the nano-foam. We expect the current catalyst to enable the manufacturing of affordable water splitting systems.
authors.affiliation: The University of Sydney, School of Chemical and Biomolecular Engineering, Sydney, New South Wales 2006, Australia. yuan.chen@sydney.edu.au.
authors.forename: Li
authors.identifier: http://orcid.org/0000-0001-8771-2921
authors.initials: L
authors.lastname: Wei
authors.affiliation: Nanyang Technological University, School of Chemical and Biomedical Engineering, 637459, Singapore.
authors.forename: Kunli
authors.identifier: http://orcid.org/0000-0001-5499-5187
authors.initials: K
authors.lastname: Goh
authors.affiliation: Koç University, Chemistry Department and KUYTAM Surface Science and Technology Center, Rumelifeneri Yolu, Sarıyer, 34450, Istanbul, Turkey.
authors.forename: Özgür
authors.initials: Ö
authors.lastname: Birer
authors.affiliation: Nanyang Technological University, School of Chemical and Biomedical Engineering, 637459, Singapore.
authors.forename: H Enis
authors.initials: HE
authors.lastname: Karahan
authors.affiliation: Nanyang Technological University, School of Chemical and Biomedical Engineering, 637459, Singapore.
authors.forename: Jian
authors.initials: J
authors.lastname: Chang
authors.affiliation: The University of Sydney, School of Chemical and Biomolecular Engineering, Sydney, New South Wales 2006, Australia. yuan.chen@sydney.edu.au and Nanyang Technological University, School of Chemical and Biomedical Engineering, 637459, Singapore.
authors.forename: Shengli
authors.initials: S
authors.lastname: Zhai
authors.affiliation: The University of Sydney, School of Chemical and Biomolecular Engineering, Sydney, New South Wales 2006, Australia. yuan.chen@sydney.edu.au.
authors.forename: Xuncai
authors.initials: X
authors.lastname: Chen
authors.affiliation: The University of Sydney, School of Chemical and Biomolecular Engineering, Sydney, New South Wales 2006, Australia. yuan.chen@sydney.edu.au.
authors.forename: Yuan
authors.identifier: http://orcid.org/0000-0001-9059-3839
authors.initials: Y
authors.lastname: Chen