Highly mesoporous hierarchical nickel and cobalt double hydroxide composite: fabrication, characterization and ultrafast NOx gas sensors at room temperature

Abstract

In this paper, highly mesoporous hierarchical nickel and cobalt double hydroxide composites (NCDHs) have been synthesized via a simple reflux method. The synthesized NCDH composites with a mass ratio of 100 : 20 for Ni(NO 3 ) 2 $6H 2 O/Co(NO 3 ) 2 $6H 2 O (NCDH-20) contained a lot of oxygen defect sites, and chemisorbed water connects the adjacent Ni(OH) 2 layers. The porous hierarchical nanostructures provide natural channels for the effective and fast transportation of carriers. Furthermore, the NCDH-20 sensor exhibits excellent gas-sensing properties, such as a low detection limit of 0.97 ppm and short response time of 0.6 s to 97 ppm NO x , due to the layered single crystal structure and unique gallery pathway. The NCDH-20 sensor with ultrafast NO x sensing has significant applications for gas sensing.

One‐Step Synthesis of CoS‐Doped β‐Co(OH)2@Amorphous MoS2+x Hybrid Catalyst Grown on Nickel Foam for High‐Performance Electrochemical Overall Water Splitting

“…The strong absorbance peaks in the range of 3000-3600 cm −1 correspond to the O-H stretching vibration of the hydrogen bond in the water molecule, and the bending of the O-H appears at 1620 cm −1 . [ 35 ] The X-ray photoelectron spectroscopy (XPS) results are in Figure 2 c-f. At the Co 2p 3/2 region in Figure 2 c, the binding energy of β-Co(OH) 2 exhibits two individual peaks at 780.4 and 782.2 eV and one shake-up satellite at about 786.0 eV. The peaks at 620-630 and 480 cm −1 are assigned to the bending of Co-OH/Ni-OH and stretching of Co-O/Ni-O, respectively.…”

Facile synthesis of mesoporous hierarchical Co3O4–TiO2 p–n heterojunctions with greatly enhanced gas sensing performance

“…Much attention has been paid to LDH because of their adjustable chemical composition, anion exchange ability, tunable charge density, and multifuntionalities, and they have been widely used in the fields of catalysis, optics, electrochemistry, adsorption, anion exchange, and polymer additives. [36][37][38][39][40] LDH have already been used as precursors to prepare different kinds of mixed metal oxides, [41][42][43] however, to the best of our knowledge, they are seldom adopted to fabricate p-n heterojunctions.…”

Alternating Voltage Introduced NiCo Double Hydroxide Layered Nanoflakes for an Asymmetric Supercapacitor

“…Figure S2 displays the thickness of NiCoDH nanoflakes is about 5 nm. Moreover, the HRTEM image reveals lattice fringes of 0.258 nm correspond to the (012) crystal plane and the nanoflakes layered structure is observed, [17][18] which is very important for faster redox reactions. [19][20] The phase of NiCoDH was determined through X-ray diffraction (XRD) tests, which is presented in Figure 1e.…”