A 3D porous Ni–Cu alloy film for high-performance hydrazine electrooxidation

Abstract

Structural design and catalyst screening are two most important factors for achieving exceptional electrocatalytic performance. Herein we demonstrate that constructing a three-dimensional (3D) porous Ni-Cu alloy film is greatly beneficial for improving the hydrazine oxidation reaction (HzOR) performance. A facile electrodeposition process is employed to synthesize a Ni-Cu alloy film with a 3D hierarchical porous structure. As an integrated electrode for HzOR, the Ni-Cu alloy film exhibits superior catalytic activity and stability to the Ni or Cu counterparts. The synthesis parameters are also systematically tuned for optimizing the HzOR performance. The excellent HzOR performance of the Ni-Cu alloy film is attributed to its high intrinsic activity, large electrochemical specific surface area, and 3D porous architecture which offers a "superaerophobic" surface to effectively remove the gas product in a small volume. It is believed that the Ni-Cu alloy film electrode has potential application in direct hydrazine fuel cells as well as other catalytic fields.

Superwettability of Gas Bubbles and Its Application: From Bioinspiration to Advanced Materials

“…The effective structures utilized in the design of superaerophilic electrodes are listed in Table 1. It is found that vertically aligned nanoplates (including Ni, [48,49] Cu 3 P, [50] Cu, [34] RuO 2 @TiO 2 , [51] and NiFe-layered double-hydroxide [52] nanoplates), 3D porous structures (amorphous MoS 2 porous thin films (PTFs) [53] ), nanoarrays composed of pine-shaped (a pine-shaped Pt nanoarray [54] ) or flower-shaped (Ni-Cu alloy nanostructure [55] ) units, and other nanostructures (ZnxCo 3−x O 4 nanoneedles grown on primary rhombus-shaped pillar arrays [56] ) are all ideal structures with which to design superaerophobic electrode interfaces to diminish the negative effects caused by the adhered gas bubbles.…”

Single Crystalline Ultrathin Nickel–Cobalt Alloy Nanosheets Array for Direct Hydrazine Fuel Cells

“…As comparisons, Ni‐NSA, reported NiCu alloy film (NiCu‐AF),26 40 wt% Pt/C, IrO 2 , and RuO 2 were also tested. The different current–voltage ( I – V ) characteristics were observed in Figure 4B and Figure S9A (Supporting Information) when using anodes with different compositions.…”

Energy‐Saving Electrolytic Hydrogen Generation: Ni2P Nanoarray as a High‐Performance Non‐Noble‐Metal Electrocatalyst

“…These observations suggest that the Ni 2 P/NF electrode is efficient for catalyzing the HzOR. Bare NF has poor HzOR activity with an egligible current density,a nd Ni(OH) 2 /NF also has very limited activity,requiring apotential of 110 mV to drive 50 mA cm À2 .R emarkably,t he Ni 2 P/NF electrode presents greatly enhanced HzOR activity and it only demands al ow potential of À25 mV to drive the same current density,which is even lower than that of Pt/C on NF (E 50 mA cm À2 = À11 mV), implying Ni 2 P/NF is superior for electrochemical HzOR catalysis.Note that it also rivals the performances of previous non-noble-metal catalysts like Cu film on Cu foam (E 50 mA cm À2 % 358 mV), [38] porous Ni-Cu alloy (E 50 mA cm À2 % 130 mV), [41] single-crystalline ultrathin Ni nanosheets arrays (E 50 mA cm À2 % 15 mV), [45] Ni nanoflowers (E 50 mA cm À2 % 60 mV), [51] and Cu nanowire arrays (E 50 mA cm À2 % 310 mV). Bare NF has poor HzOR activity with an egligible current density,a nd Ni(OH) 2 /NF also has very limited activity,requiring apotential of 110 mV to drive 50 mA cm À2 .R emarkably,t he Ni 2 P/NF electrode presents greatly enhanced HzOR activity and it only demands al ow potential of À25 mV to drive the same current density,which is even lower than that of Pt/C on NF (E 50 mA cm À2 = À11 mV), implying Ni 2 P/NF is superior for electrochemical HzOR catalysis.Note that it also rivals the performances of previous non-noble-metal catalysts like Cu film on Cu foam (E 50 mA cm À2 % 358 mV), [38] porous Ni-Cu alloy (E 50 mA cm À2 % 130 mV), [41] single-crystalline ultrathin Ni nanosheets arrays (E 50 mA cm À2 % 15 mV), [45] Ni nanoflowers (E 50 mA cm À2 % 60 mV), [51] and Cu nanowire arrays (E 50 mA cm À2 % 310 mV).…”

“…[36][37][38][39][40][41][42] Compared with the above oxidizable species,hydrazine has the following advantages: [43][44][45] 1) its electrooxidation only releases nitrogen and water without greenhouse gas;2 )ith as no carbon atoms, thereby avoiding the generation of catalyst-poisoning species; 3) its stronger reducing power lowers the oxidation potential. [36][37][38][39][40][41][42] Compared with the above oxidizable species,hydrazine has the following advantages: [43][44][45] 1) its electrooxidation only releases nitrogen and water without greenhouse gas;2 )ith as no carbon atoms, thereby avoiding the generation of catalyst-poisoning species; 3) its stronger reducing power lowers the oxidation potential.…”