以三聚氰胺为原料,Li2 CO3为掺杂剂,分别在450,550,600,650,680℃热解60 min制备了g-C3 N4粉体,在650℃热解60 min制备了Li+质量分数分别为0.5%,1.0%,1.5%,2.5%的Li+/g-C3 N4粉体,研究了热解温度和Li+质量分数对粉体物相组成、微观形貌和光催化性能的影响.结果表明:随热解温度的升高,g-C3 N4粉体的纯度增加,晶型结构逐渐完善,对亚甲基蓝的降解率逐渐增加,当热解温度为650℃时,g-C3 N4粉体具有完善的晶型结构,平均粒径为200 nm,光催化性能最佳;Li+掺杂没有改变g-C3 N4结构,但细化了其粒径并提高了其光催化性能,当Li+质量分数为1.5%时,Li+/g-C3 N4粉体的平均粒径为150 nm,在光照240 min条件下,对亚甲蓝的降解率达到91.0%,比g-C3 N4粉体的提高了57.2%.%With melamine as raw material and Li2 CO3 as dopant,g-C3 N4 powder was synthesized by pyrolysis at 450,550,600,650,680 ℃ for 60 min,and Li+/g-C3 N4 powders were also synthesized with Li+ mass fractions of 0.5%,1.0%,1.5% and 2.5% by pyrolysis at 650 ℃ for 60 min,respectively.The effects of pyrolysis temperature and Li+mass fraction on the phase composition,micromorphology and photocatalytic performance of the powders were investigated.The results show that with the rise of pyrolysis temperature,the purity of g-C3 N4 powders increased,the crystal structure gradually improved,and the degradation efficiency of methylene blue increased.When the pyrolysis temperature was 650 ℃,the g-C3 N4 powder had a perfect crystal structure with the average particle size of 200 nm,whose photocatalytic performance was the best.The structure of g-C3 N4 was not changed by Li+ doping,while the particle size was refined and the photocatalytic performance was improved.With Li+ mass fraction of 1.5%,the average particle size of Li+/g-C3 N4 powder was 150 nm;the degradation efficiency of methylene blue reached 91% after irradiation for 240 min,which was 57.2% higher than that of the g-C3 N4 powder.
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