g-C_(3)N_(4)/TiO_(2)/RGO三元复合材料的制备及催化果糖脱水制5-羟甲基糠醛的研究

Preparation of g-C_(3)N_(4)/TiO_(2)/RGO ternary composites and catalytic dehydration of fructose to 5-hydroxymethylfurfural

采用水热法制备g-C_(3)N_(4)/TiO_(2)/RGO三元复合材料,并将其应用于果糖脱水制备5-羟甲基糠醛(5-HMF)。利用SEM、TEM、XRD、FTIR、BET等检测手段对g-C_(3)N_(4)/TiO_(2)/RGO三元复合材料的形貌、晶型、基团和比表面积进行了表征,同时研究了反应温度、反应时间、催化剂用量及溶剂种类对果糖转化率、5-HMF的收率和选择性的影响,此外,还考察了催化剂的稳定性。结果表明,g-C_(3)N_(4)/TiO_(2)/RGO三元复合材料具有三维立体网状结构,比表面积达到了31.4782 m^(2)/g,对果糖脱水反应具有良好的催化活性;在果糖质量为5.0 g、二甲基亚砜用量15 mL、g-C_(3)N_(4)/TiO_(2)/RGO用量1.0 g、反应时间3 h、反应温度150℃的条件下,果糖的转化率为98.5%,5-HMF的收率为69.7%,选择性为70.8%;5次循环使用后,5-HMF的收率仍能达到58.8%,表明g-C_(3)N_(4)/TiO_(2)/RGO三元复合材料的催化稳定性良好。

The g-C_(3)N_(4)/TiO_(2)/RGO ternary composite was prepared by hydrothermal method and applied to the dehydration of fructose to 5-hydroxymethylfurfural(5-HMF).The morphology,crystal form,group and specific surface area of g-C_(3)N_(4)/TiO_(2)/RGO ternary composites were characterized by SEM,TEM,XRD,FTIR and BET.The effects of reaction temperature,reaction time,catalyst dosage and solvent type for fructose conversion,5-HMF yield and selectivity were studied,and the stability of the catalyst was also investigated.The results showed that the g-C_(3)N_(4)/TiO_(2)/RGO ternary composites had complex three-dimensional network structure,and the specific surface area reached 31.4782 m^(2)/g.The g-C_(3)N_(4)/TiO_(2)/RGO ternary composites had good catalytic activity for fructose dehydration reaction.Under the conditions of fructose quality 5.0 g,dimethyl sulfoxide 15 mL,g-C_(3)N_(4)/TiO_(2)/RGO dosage 1.0 g,reaction time 3 h and reaction temperature 150℃,the conversion of fructose was 98.5%,the yield of 5-HMF was 69.7%and the selectivity was 70.8%.After five cycles,the yield of 5-HMF still reached 58.8%.