Fundamental Understanding of Lignin Transformation into Graphene via Direct Laser Writing for Energy Storage

激光直接写入(DLW)是一种以激光为能源，从不同的碳前驱体制备多孔石墨烯的非传统技术。木质素含量较高的生物质似乎是DLW生成石墨烯的合适原料，但从生物质中产生木质素用于激光诱导石墨烯(LIG)的潜在机制尚不清楚。此外，在激光诱导的反应条件下，木质素转化为石墨烯的机制还不清楚。这项拟议的研究旨在加深对木质素通过DLW转化为石墨烯的基础了解，并开发一种新的工艺，将造纸厂和生物炼油厂产生的废木质素升级为用于储能的多孔石墨烯。这项拟议的研究将从孔隙率、组成和石墨化程度方面调查木质素的化学和结构如何影响LIG的性能。将研究木质素-激光相互作用的光热和光化学效应，以确定控制LIG特性的关键激光参数(例如，功率、扫描速度、图像密度)。通过反应力场分子动力学(ReaxFFMD)模拟，在原子水平上研究了木质素转化为LIG的瞬时化学和物理过程。木质素衍生的LIG将被开发为超级电容器的活性电极材料。该项目将对研究生和本科生进行研究培训，重点是招募代表性不足的少数群体成员加入研究团队。将根据拟议研究产生的知识开发一门新的高级本科生/研究生课程。该基金会还计划为K-12年级的学生开发教学模块，以激发他们追求STEM职业生涯的兴趣。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Direct laser writing (DLW) is an unconventional technique for producing porous graphene from variouscarbon precursors using a laser as an energy source. Biomass with higher lignin content appears to be a suitable feedstock for graphene formation by DLW, but the underlying mechanisms of lignin production from biomass for laser-induced graphene (LIG) production are not well understood. Furthermore, the mechanisms involved in lignin conversion into graphene under laser-induced reaction conditions also remain unclear. The proposed research aims to develop fundamental understanding of lignin transformation into graphene via DLW and develop a new process for upgrading waste lignin produced by paper mills and biorefineries into porous graphene for energy storage applications. The proposed research will investigate how lignin chemistry and structure affect LIG properties in terms of porosity, composition and degree of graphitization. Photothermal and photochemical effects of lignin-laser interactions will be studied to identify key laser parameters (e.g., power, scanning speed, image density) governing LIG properties. Transient chemical and physical processes of lignin-to-LIG will be studied at the atomic level by reactive force field molecular dynamics (ReaxFF MD) simulations. The lignin-derived LIG will be explored as active electrode material for supercapacitors. The project will train graduate and undergraduate students in research, with a focus on recruiting members of underrepresented and minority groups to join the research team. A new upper level undergraduate/graduate course will be developed based on the knowledge generated from the proposed research. There is also a plan for developing teaching modules for K-12 students to stimulate their interest into pursuing STEM careers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.