【作者】 李斌；

【导师】 郭贵宝；

【作者基本信息】 内蒙古科技大学 ， 化学工程与技术， 2023， 硕士

【摘要】 化石燃料过度消耗造成的能源短缺问题一直是制约经济高速发展的重要因素。生物质衍生的脂肪酸由于它们与生物燃油型碳氢化合物具有内在的结构相似性、来源丰富,被视为很有希望的初始原料。光催化技术因独特的反应活性、温和的反应条件,受到人们广泛关注。然而,现存的光催化脂肪酸脱羧体系存在目标产物产出效率低、选择性差及消耗大量氢源等问题,因此开发出高效的脱羧体系成为重中之重。该论文在常压条件下,建立了一种廉价、高效的光热脱羧体系体系,具体工作概括如下:（1）选用商业纳米Fe粉为催化剂,硬脂酸为原料,探究了温度、溶剂、底物等反应条件对光催化硬脂酸脱羧的影响。结果表明,在200 nm Fe粉催化剂、可见光（410 nm LED,768 W）的照射下,无任何额外热源,0.05 M硬脂酸反应3 h后完全转化。动力学研究揭示Fe光催化硬脂酸脱羧反应为一级反应,活化能为48.79 k J·mol^-1,这远低于传统的热催化脂肪酸脱羧反应的活化能(～100 k J·mol^-1),量子产率从125.8℃不足1%提高到235.4℃的25%。各种脂肪酸均能以80%的收率转化。详细的机理研究表明,光热促使Fe产生LSPR效应,这提供足够的能量克服连续的势垒,激发高能载流子的跃迁从而参与反应。此外,循环实验和XRD表明Fe催化剂具有良好的稳定性。（2）选用商业纳米Cu粉为催化剂,硬脂酸为原料,考察了催化剂用量、溶剂、温度、时间、底物等反应条件对光催化硬脂酸脱羧的影响;探究了催化剂的重复使用性能。结果表明,在无外部热源条件下,以200 nm Cu粉为催化剂,硬脂酸在365 nm LED（768 W）光照6 h下反应掉57%。动力学研究表明Cu光催化脱羧反应也符合一级反应动力学特征,活化能为12.30 k J·mol^-1,量子产率从0.1%以下增加到高温（235.4℃）条件下的3%。机理研究表明,光热诱导Cu产生LSPR效应,产生高能载流子,增加了分子的传质,提高光催化脂肪酸脱羧。循环实验也表明Cu具有良好的稳定性。更多还原

【Abstract】 Energy shortage caused by excessive consumption of fossil fuels has always been an important factor restricting the rapid economic development.Biomass-derived fatty acids are considered to be promising starting materials due to their intrinsic structural similarity and abundant sources with biofuel-type hydrocarbons.Photocatalytic technology has attracted wide attention due to its unique reactivity and mild reaction conditions.However,the existing photocatalytic fatty acid decarboxylation system has problems such as low yield of target products,poor selectivity,and consumption of a large amount of hydrogen sources.Therefore,the development of an efficient decarboxylation system has become a high priority.In this thesis,a cheap and efficient photothermal decarboxylation system system was developed under atmospheric pressure conditions,and the specific work is summarized as follows:（1）The effects of reaction conditions such as temperature,solvent and substrate on photocatalytic decarboxylation of stearic acid were investigated by using commercial nano-Fe powder as catalyst and stearic acid as raw material.The results showed that under the irradiation of 200 nm Fe powder catalyst and visible light（410 nm LED,768 W）,0.05 M stearic acid was completely converted after 3 h without any additional heat source.Kinetic studies revealed that the Fe photocatalytic stearic acid decarboxylation reaction was a first-order reaction,and the activation energy was 48.79 k J·mol^-1,which was much lower than that of the traditional thermal catalytic fatty acid decarboxylation reaction(～100 k J·mol^-1),the quantum yield increased from less than 1%at 125.8°C to 25%at 235.4°C.All kinds of fatty acids can be converted in 80%yield.Detailed mechanism studies show that photothermal promotes the LSPR effect of Fe,which provides sufficient energy to overcome the continuous barrier and excite the transition of high-energy carriers to participate in the reaction.In addition,cycle experiments and XRD showed that the Fe catalyst had excellent stability.（2）The effects of reaction conditions such as catalyst dosage,solvent,temperature,time and substrate on photocatalytic decarboxylation of stearic acid were investigated by using commercial nano-Cu powder as catalyst and stearic acid as raw material.The reusability of the catalyst was investigated.The results showed that under the condition of no external heat source,with 200 nm Cu powder as catalyst,stearic acid reacted at 365 nm LED（768 W）for 6 h and 57%of the reaction was lost.The kinetic study shows that the photocatalytic decarboxylation reaction of Cu also conforms to the first-order reaction kinetics.The activation energy is 12.30 k J·mol^-1,and the quantum yield increases from below 0.1%to 3%at high temperature（235℃）.The mechanism study shows that photothermally induced Cu to produce LSPR effect,generate high-energy carriers,increase the mass transfer of molecules,and improve the photocatalytic fatty acid decarboxylation.Cyclic experiments also show that Cu has good stability.更多还原