Synthesis-directed morphological control of NiOx nanomaterials: the role of base, precursor, and calcination temperature
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Published online version
Author(s)
Type
Journal Article
Abstract
Nickel oxide (NiOx) nanoparticles are widely studied as earth-abundant p-type metal oxide semiconductors, and numerous applications spanning emerging electronic, optoelectronic and energy-related devices have been proposed. In this work, we systematically investigate the impact of modifying the nickel precursor, precipitating base and calcination temperature on the formation of NiOxvia a chemical precipitation synthesis, identifying the critical role of intermediate phases in controlling final product morphology. We investigate the products prepared by precipitating nickel acetate/nitrate with sodium hydroxide/bicarbonate and show that the intermediates formed, crystalline nickel hydroxide (Ni(OH)2) or amorphous basic nickel carbonate (Nim(OH)n(CO3)p), are directly governed by the choice of base. The morphology of the intermediates is further dependent on the nickel precursor; the crystalline Ni(OH)2 prepared from Ni(NO3)2 yields flake-like structures, whilst Ni(OAc)2 results in spherical particles and those precipitated using NaHCO3 result in spherical particles. Thermal analysis of the intermediates reveals the temperature range of their degradation and subsequent NiOx formation, with calcination carried out at 270, 450 and 650 °C. The spherical intermediates retain this morphology; however, they progressively coarsen with increasing temperature, whilst the flake-like structures evolve into ring-like features at 450 °C that then fragment at 650 °C. Overall, our results establish clear links between the precursor chemistry, intermediate-phase formation, and decomposition pathway during calcination, demonstrating how these stages collectively govern the structure, surface structure chemistry and morphology of the resulting NiOx. These findings provide a practical framework for rationally tuning NiOx powders through low-complexity, wet-chemical processing, and are also relevant to the broader preparation of metal oxide nanomaterials.
Date Issued
2026-08-17
Date Acceptance
2026-08-09
Citation
Journal of Materials Chemistry C, 2026
ISSN
2050-7526
Publisher
Royal Society of Chemistry (RSC)
Journal / Book Title
Journal of Materials Chemistry C
Copyright Statement
© 2026 The Author(s). Published by the Royal Society of Chemistry This article is licensed under a Creative Commons Attribution 4.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.
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Publication Status
Published online
Date Publish Online
2026-08-17