Shape controlled synthesis of hierarchical nickel sulfide by the hydrothermal method

Abstract

Hierarchical structures of nickel sulfide have been grown by the hydrothermal method. Nickel nitrate hexahydrate and thiourea were used as precursor materials to synthesize nickel sulfide. Ethylenediaminetetraacetic acid was used as a capping agent to achieve monodispersity. The different phases of nickel sulfide and its dependency on the precursor concentration were analyzed by X-ray diffractometry. Transmission electron microscopy analysis was used to confirm the phase changes and morphological behavior of the synthesized material. The morphological evolution of the hierarchical structure formation was studied systematically by scanning electron microscopy. In this study, we explore a novel method to control the synthesis of nickel sulfide hierarchical structures by varying the precursor concentration. The two mixed phases enhanced the catalytic activity in the 4-nitro phenol reduction reaction.

Enhanced Hydrogen Evolution Catalysis at the Liquid/Liquid Interface by NixSy and NixSy/Carbon Nanotube Catalysts

“…Similar results were reported by Karthikeyan et al Further, a surplus in the concentration of sulfur with a nickel/sulfur ratio of approximately 1:2 results in the creation of Ni 17 S 18 and Ni 3 S 4 stable phases with random frequent sheets composed of hierarchy morphologies on the surface of the CNTs, as shown in Figure b. A detailed view is given in Figure S1 (Supporting Information).…”

“…[39,40] JCPDS card number 00-058-1638 for the carbon nanotubes, and JCPDS card number 01-076-1813 for a small amount of the Ni 3 S 4 (polydymite) phase, which can be seen from a shift in the dominant peak locations (diffraction planes) from 25.9°(002) for the carbon nanotubes (hexagonal graphite structure) [41,42] (Figure 1). [43] Figure 2 shows SEM images as a means to characterize the surface structures and morphologies of the Ni x S y nanoparticles and Ni x S y /CNT nanocomposite. In Figure 2a, the Ni x S y nanopar- ticles are ball-like and clustered.…”

“…All of the diffraction peaks of the Ni x S y nanoparticles can be well matched with JCPDS card number 01‐089‐7141 for the NiS (millerite) phase and JCPDS card number 01‐076‐2306 for the Ni 17 S 18 phase. On the other hand, all of the diffraction peaks of the Ni x S y /CNT sample can be well matched with JCPDS card number 03‐065‐3686 for the rhombohedral NiS (millerite) phase, JCPDS card number 01‐076‐2306 for hexagonal Ni 17 S 18 , JCPDS card number 00‐058‐1638 for the carbon nanotubes, and JCPDS card number 01‐076‐1813 for a small amount of the Ni 3 S 4 (polydymite) phase, which can be seen from a shift in the dominant peak locations (diffraction planes) from 25.9° (002) for the carbon nanotubes (hexagonal graphite structure), phase and 30.3 (101), 32.2 (300), 35.7 (021), 37.3 (220), 40.4 (211), 48.8 (131), 50.1 (410), 52.6 (401), 56.2 (321), 57.4 (330), 59.7 (012), 67.3 (600), and 75.6° (431) for the rhombohedral NiS (millerite) phase; the positions of the peaks (planes) at 34.5 (033), 45.6 (306), 53.3 (330), and 73.5° (440) are consistent with the hexagonal Ni 17 S 18 phase, and as the last Ni 3 S 4 (polydymite) phase, the positions of the peaks (planes) are 26.6 (220), 31.3 (311), and 38.0° (400) (Figure ) …”

Single-step synthesis and catalytic activity of structure-controlled nickel sulfide nanoparticles

“…other phases within the synthesized product 19 . The synthesis of nickel sulfide phases such as Ni 3 S 4 requires a two-step reduction process 20 to control the phase and morphology.…”

“…We have developed a single-step injection process, using oleylamine as both the solvent and the reducing agent, to obtain the desired phases in the nickel sulfide binary phase diagram. We described the synthesis and evolution of hierarchical nickel sulfide architectures in our previous communication 19 .…”