Controllable Synthesis of Ni_xSe (0.5 ≤ x ≤ 1) Nanocrystals for Efficient Rechargeable Zinc–Air Batteries and Water Splitting

Abstract

The development of earth-abundant, highly active, and corrosion-resistant electrocatalysts to promote the oxygen reduction reaction (ORR) and oxygen and hydrogen evolution reactions (OER/HER) for rechargeable metal-air batteries and water-splitting devices is urgently needed. In this work, Ni Se (0.5 ≤ x ≤ 1) nanocrystals with different crystal structures and compositions have been controllably synthesized and investigated as potential electrocatalysts for multifunctional ORR, OER, and HER in alkaline conditions. A novel hot-injection process at ambient pressure was developed to control the phase and composition of a series of NiSe by simply adjusting the added molar ratio of the nickel resource to triethylenetetramine. Electrochemical analysis reveals that NiSe nanocrystalline exhibits superior OER activity compared to its counterparts and is comparable to RuO in terms of the low overpotential required to reach a current density of 10 mA cm (330 mV), which may benefit from the pyrite-type crystal structure and Se enrichment in NiSe. For the ORR and HER, NiSe nanoparticles achieve the best performance including lower overpotentials and larger apparent current densities. Further investigations demonstrate that NiSe could not only provide an enhanced electrochemical active area but also facilitate electron transfer during the electrocatalytic process, thus contributing to the remarkable catalytic activity. As a practical application, the NiSe electrode enables rechargeable Zn-air battery with a considerable performance including a long cycling lifetime (200 cycles), high specific capacity (609 mA h g based on the consumed Zn), and low overpotential (0.75 V) at 10 mA cm. Meanwhile, the water-splitting cell setup with an anode of NiSe for the HER and a cathode of NiSe for the OER exhibits a considerable performance with low decay in activity of 12.9% under continuous polarization for 10 h. These results suggest the promising potential of nickel selenide nanocrystals as earth-abundant and high-performance electrocatalysts for metal-air batteries and alkaline water splitting.

Nickel@Nitrogen‐Doped Carbon@MoS2 Nanosheets: An Efficient Electrocatalyst for Hydrogen Evolution Reaction

“…Therefore, many efforts have been devoted to design and fabricate nonprecious metal electrocatalysts for HER. Over the past few years, nonprecious metal–based electrocatalysts such as transition metal sulphides, selenide, nitrides, phosphides, and carbides have been developed as good candidates for HER.…”

Pt embedded Ni3Se2@NiOOH core-shell dendrite-like nanoarrays on nickel as bifunctional electrocatalysts for overall water splitting

“…However, the high cost, terrestrial scarcity and non-bifunctional property impede their widespread utilization [4][5][6]. During the past decades, non-noble metal oxides, hydroxides, chalcogenides, phosphides and nitrides have attracted special attention as bifunctional catalysts for OER and HER due to their cost-competitiveness, high abundance and environmental friendliness [7][8][9][10][11][12][13][14]. Unfortunately, their electrochemical properties are still far away from that of noble metal catalysts due to the limited active sites and poor electrical conductivity.…”

Structural, magnetic, and optical properties of nano‐sized Ni0.85Se

“…Subbarao et al revealed that NiSe prepared by ball milling has a slightly better activity compared to the same composition synthesized by solution procedure. Moreover, Zheng et al found promising potential applications for nickel selenide nanocrystals as earth‐abundant and high‐performance electrocatalysts for metal‐air batteries and alkaline water splitting. Tang et al used NiSe Nano wire film on nickel foam as an electrode for high‐performance supercapacitors.…”