本研究以化學沉澱法製備氫氧化鎳，再以高溫煅燒而產生氧化鎳粒子。主要以氯化鎳為前趨鹽，氨水作為沉澱劑，於室溫下反應30分鐘即可獲得。當[NH3]/[Ni2+]比例為1.28時，於低濃度氫氧化鎳水溶液(0.05wt%)下，經超音波震盪後作粒徑儀分析結果顯示，可以得到平均粒徑約70nm之氫氧化鎳粒子，此時轉化率約為70%。再進一步分析氫氧化鎳粒子之界面電位，當溶液pH為3.5時，粒子表面電位為28.6mV，此時粒子間具有良好的排斥力。再進而由熱重分析(TGA)及X光繞射(XRD)分析的結果顯示，當煅燒溫度為400℃時，氫氧化鎳已轉變為氧化鎳粒子。

而隨著煅燒溫度的不同，會產生不同顏色的粉末。當煅燒溫度700℃一小時，可得到綠色氧化鎳粉末，由反射式UV檢測後發現，主要波峰於波長510nm處 (波長範圍510~570nm為綠色)。再以XPS分析不同煅燒溫度下，發現氧化鎳的組成為Ni2O3 (黑色)和NiO (綠色)。其中NiO (綠色)的含量，由煅燒溫度400℃的36.9%增加至800℃之60.4%，故氧化鎳粉末顏色亦從400℃時之灰黑色，慢慢轉變為800℃之綠色，証明了氧化鎳粉末顏色改變的原因。

In this work, nickel oxide has been successfully synthesized by high temperature calcination of nickel hydroxide (Ni(OH)2) prepared at first by chemical precipitation, in which Ni(OH)2 was obtained after 30 minutes of the reaction at room temperature using nickel chloride as precursor and ammonia as precipitating agent. At the [Ni2+] concentration was 0.1M and the molar ratio of [NH3]/[Ni2+]=1.28, we could obtain Ni(OH)2 colloids of average size 70 nm measured by dynamic light scattering technique, at the same time the conversion was about 70%. As the colloids’ pH was 3.5, the zeta potential of these particles is 28.6mV, which is large enough to stabilize the solution against aggregation between particles themselves. In addition, by our data of XRD and TGA, we proved the dried Ni(OH)2 powders had totally converted to nickel oxide after 400℃ calcination.
Besides, the powders with different calcination temperatures could exhibit different colors. In our case green powders ( By reflex UV instrument, peak of wavelength is 510 nm) could be obtained after 1h calcination at 700℃. By XPS analysis, we confirmed these powders calcined with temperature above 400℃ were only a mixture of Ni2O3 (black) and NiO (green). The computed content of NiO was 36.9% and 60.4% after respective 400℃ and 800℃ calcinations for 1h, and that is the reason for the change in color of nickel oxide powders.

Bai, L.Y., F.G. Yuan, P. Hu, S.K. Yan, X. Wang and S.H. Li, “A facile route to sea urchin-like NiO architectures” Material Letters, (2006)

Chastain, J., Handbook of X-ray Photoelectron Spectroscopy, p85, Perkin-Elmer Corporation, Minnesota, USA(1992)

Deng, X.Y. and Z. Chen, “Preparation of nano-NiO by ammonia precipitation and reaction in solution and competitive balance”, Materials Letters, 58, p.276-280, (2004)

Guan, X.Y. and J.C. Deng, “Preparation and electrochemical performance of nano-scale nickel hydroxide with different shapes” , Materials Letters, 61, p.621-625, (2007)

Han, D.Y., H.Y. Yang, C.B. Shen, X. Zhou and F.H. Wang, “Synthesis and size control of NiO nanoparticles by water-in-oil microemulsion”, Powder Technology, 147, p.113-116, (2004)

Lai, T.L., Y.Y. Shu, G.L. Huang, C.C. Lee and C.B. Wang, “Microwave-assisted and liguid oxidation combination techniques for the preparation of nickel oxide nanoparticles” , Journal of Alloys and Compounds, (2006)

Li G J., Huang X.X., Shi, Y. et al. “Preparation and characteristic of nanocrystalline NiO by organic solvent method”, Materials Letters. 51, p325-330. (2001)

Liu, X.M., X.G. Zhang and S.Y. Fu, “Preparation of urchinlike NiO nanostructures and their electrochemical capacitive behaviors”, Materials Research Bulletin, 41, p.620-627, (2006)

Lenggoro, I.W., Y. Itoh, N. Iida, K. Okuyama, “Control of size and morphology in NiO particles perpared by a low-pressure spray pyrolysis”, Materials Research Bulletin, 38, p.1819-1827, (2003)

Li, Q., L.S. Wang, B.Y. Hu, C. Yang, L. Zhou and L. Zhang, “Preparation and characterization of NiO nanoparticles through calcinations of malate gel” ,Materials Letters, (2006)

Meek, T.T., “Synthesis of ultrafine powders by microwave heating”, Knoxville, US Patent：4784686, 1988-11-15.

R.Lide, D., Handbook of Chemistry and Physics, 84th ed., p.4-72, USA(2003)

Tokeer Ahmad, Kandalam V.Ramanujachary, Samuel E. Lofland, Ashok K. Ganguli, “Magnetic and electrochemical properties of nickel oxide nanoparticles obtained by the reverse-micellar route”, Solid State Sci, 8, p425-430 (2006)

Wang, W.H., Y.K. Liu and C.K. Xu , “Synthesis of NiO nanorods by a novel simple precursor thermal decomposition approach”, Chemical Physics Letters, 362(1-2), p119-122 (2002)

Wang Y. and Ke J.“Preparation of nickel oxide powder by decomposition of basic nickel carbonate in microwave field with nickel oxide seed as a microwave-absorbing additive”, Materials Research Bulletin, 31(1), p55-61 (1996)

Wang, S.F., L.Y. Shi, X. Feng and S.R. Ma, “Eutectic assisted synthesis of nanocrystalline NiO through chemical precipitation”, Materials Letters, (2006)

Xiang, L., X.Y. Deng and Y. Jin, “Experimental study on synthesis of NiO nano-particles”, Scripta Materials, 47, p.219-224, (2002)

Xin, X.S., Z. Lu, B.B. Zhou, X.Q. Huang, R.B. Zhu, X.Q. Sha, Y.H. Zhang and W.H. Su, “Effect of synthesis conditions on the performance of weakly agglomerated nanocrystalline NiO”, Journal of Alloys and Compounds, (2006)

Zhou, G.T., Q.Z. Yao, X.C. Wang and Jimmy C. Yu, “Preparation and characterization of nanoplatelets of nickel hydroxide and nickel oxide”, Materials Chemistry and Physics, 98, p.267-272, (2006)

朱誠意, 劉中華, 陳雯. “奈米NiO粉體的製備及其表徵”, 有色礦冶, 18(1), p42-44. (2002)

楊霞, 張高科, 胡波, 劉穎. “奈米NiO粉體的製備及其應用”, 中國非金屬礦工業專刊, 42, 23 (2004)

張信貞，“數位噴墨簡介及其在建材的應用”，化工資訊與商情, No.38, p.46-57 (2006)

郭宏達，“鎳絲的合成及其在電磁波遮蔽材料上的應用”，國立清華大學碩士論文 (2003)

黃國政，“化學還原法製備奈米鎳微粒之機制及其特性探討”，國立清華大學碩士論文 (2001)