A series of α-Fe₂O₃ catalysts were prepared by precipitation method by changing calcination temperatures, solvents, precursor concentration, and bases. The structure and morphology of the synthesized catalysts were characterized by SEM, XRD, XPS, and Raman spectroscopy, and the liquid-phase spin conversion of ortho-hydrogen to para-hydrogen was performed by in situ FTIR spectroscopy at cryogenic temperature 17 K. The spin conversion was affected by catalysts calcination temperature, initial precursor concentration, solvents used, and precipitating agent. The highly dispersed and most active α-Fe₂O₃ was obtained using double-distilled water as solvent and sodium hydroxide solution as precipitating agent followed by calcination at 393 K for 12 h. The formation of hydrated Fe (OH)₃ or FeOOH during synthesis of α-Fe₂O₃ at 393 K dramatically enhanced the catalytic activity and ortho to para-hydrogen spin conversion.

中文翻译：

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液态氢自旋转化的高效α-Fe2 O 3催化剂的合成

一系列的α-Fe的_2个ö ₃催化剂是通过改变煅烧温度，溶剂，前体浓度，和碱制备由沉淀法。用SEM，XRD，XPS和Raman光谱对合成的催化剂的结构和形貌进行了表征，并在17 K的低温下通过原位FTIR光谱将原氢液相转化为对氢。自旋转化率受催化剂煅烧温度，初始前体浓度，所用溶剂和沉淀剂的影响。高度分散的和最活跃的α-Fe ₂ ö ₃用双蒸馏水作为溶剂，用氢氧化钠溶液作为沉淀剂，然后在393 K下煅烧12 h，得到水。水合的Fe（OH）的形成₃或针铁矿的α-Fe的合成期间₂ ö ₃在393K的显着增强的催化活性和邻位的仲氢的自旋转换。