Bifunctional Nickel Phosphide Nanocatalysts Supported on Carbon Fiber Paper for Highly Efficient and Stable Overall Water Splitting

Abstract

Self-supported electrodes comprising carbon fi ber paper (CP) integrated with bifunctional nickel phosphide (Ni-P) electrocatalysts are fabricated by electrodeposition of Ni on functionalized CP, followed by a convenient one-step phosphorization treatment in phosphorus vapor at 500 °C. The as-fabricated CP@Ni-P electrode exhibits excellent electrocatalytic performance toward hydrogen evolution in both acidic and alkaline solutions, with only small overpotentials of 162 and 250 mV, respectively, attaining a cathodic current density of 100 mA cm −2 . Furthermore, the CP@Ni-P electrode also exhibits superior catalytic performance toward oxygen evolution reaction (OER). An exceptionally high OER current of 50.4 mA cm −2 is achieved at an overpotential of 0.3 V in 1.0 M KOH. The electrode can sustain 10 mA cm −2 for 180 h with only negligible degradation, showing outstanding durability. Detailed microstructural and compositional studies reveal that upon OER in alkaline solution the surface Ni-P is transformed to NiO covered with a thin Ni(OH) x layer, forming a Ni-P/NiO/Ni(OH) x heterojunction, which presumably enhances the electrocatalytic performance for OER. Given the well-defi ned bifunctionality, a full alkaline electrolyzer is constructed using two identical CP@Ni-P electrodes as cathode and anode, respectively, which can realize overall water splitting with effi ciency as high as 91.0% at 10 mA cm −2 for 100 h.

Multifunctional non-woven fabrics of interfused graphene fibres

“…Benefiting from the interfused network and an all-graphene structure, our binder-free GFFs outperform commercially available carbon fibre papers on both conductivity and flexibility. In view of the broad application of carbon fibre papers in the green energy fields, such as gas diffusion layers for fuel cells5152 and electrodes for energy storage535455 and water splitting56 devices, the GFFs should become an alternative choice showing a great appeal. Our preliminary attempt to build supercapacitors using 130GFF-N 2 H 4 as electrodes revealed remarkable gravimetric (206 F g −1 at a current density of 1 A g −1 ) and areal capacitance (220 mF cm −2 at 1 mA cm −2 ; see Supplementary Fig.…”

Preparation and Characterization of Nicke-iron Alloy Film as Freestanding Electrode for Oxygen Evolution Reaction

“…Hydrogen has been considered as a promising alternative to fossil fuels [1][2][3]. As our known, electrochemical water spliting is an efficient way to generate hydrogen [4,5].…”

Acid promoted Ni/NiO monolithic electrode for overall water splitting in alkaline medium

“…As a result, the pulverized catalysts tend to peel off from the substrate especially in a working circumstance where lots of hydrogen and oxygen would continuously bubble up, leading to gradually decreased catalytic efficiency as well as limited life span [25]. In comparison, growing the catalysts directly onto the conductive substrate such as Ni foam (NF) [26,27], carbon cloth [28,29], carbon fiber paper [30] and Ti foil [31] can mitigate the problem of falling off and contact to some extent. However, the matter of the contact interface between electrocatalysts and the current collector as well as pulverization issues is still not fully addressed.…”