微流控技术辅助制备多孔石墨相氮化碳(g-C3N4)块体及其性能研究

Microfluidic-assisted preparation of porous graphitic carbon nitride block and study on its properties

设计了适用于微流控系统的原位生成酸催化聚乙烯醇/戊二醛凝胶反应体系并用于g-C_(3)N_(4)多孔微球粒径与形貌的可控制备,以无机粘结剂和多孔微球为原料实现氚兼容的多孔g-C_(3)N_(4)块体的制备。考察了凝胶组成成分、煅烧模式对微球比表面积与机械强度的影响,以及无机黏合剂质量分数、微球粒径对g-C_(3)N_(4)块体比表面积与机械强度的影响。结果表明,微球粒径对块体材料性能有显著影响,在相同成型黏合剂质量分数下,微球粒径增加79.5%块体材料的比表面积提高205%,而机械强度仅降低了42%。4.5 K低温气体吸附实验结果表明,所制备的g-C_(3)N_(4)多孔块体吸附层对氢气和氦气的选择性系数可达13.02。

An acid-catalyzed polyvinyl alcohol-glutaraldehyde gel reaction system with an in-situ acid formation process is designed to prepare size-and morphology-controllable porous g-C_(3)N_(4)microspheres in a microfluidic system.A tritium-compatible porous g-C_(3)N_(4)block is fabricated by using inorganic binder and porous microspheres as raw materials.The effects of gel composition and calcination mode on the specific surface area and mechanical strength of the porous g-C_(3)N_(4)microspheres,as well as the effects of inorganic binder mass fraction and microsphere size on the specific surface area and mechanical strength of the resulting g-C_(3)N_(4)blocks are investigated.It is shown by the results that the microsphere size has a significant impact on the properties of the block materials.Under the same binder mass fraction,increasing microsphere size by 79.5%results in a 205%increase in specific surface area of the blocks,while only 42%decrease in its mechanical strength.It is proved from a cryo gas adsorption experiment at 4.5 K that the selectivity of the prepared g-C_(3)N_(4)porous block adsorption layer for hydrogen over helium can reach 13.02.