CAREER: Synthesis Methods to Control Framework Aluminum Distribution in Zeolites for NOx Pollution Abatement Catalysis

摘要（Gounder; 1552517）本研究将开发新的合成策略来控制用于氮氧化物（NOx）减排和碳原料转化为燃料和化学品的沸石催化剂中铝（Al）活性位点的分布。调整沸石中活性位点的接近度和分布将为环境保护和碳转化领域的催化创新开辟新的机会，同时也为沸石结晶的化学性质提供新的见解。这项研究将与STEM领域的教育和指导计划联系起来，面向各级学生。目前，人们对沸石中Al原子的排列与用于合成它们的前驱体溶液和凝胶的化学性质之间的关系知之甚少。这项工作是基于沸石中催化相关的分离和配对Al位点的分布可以由合成凝胶的电荷密度控制的假设。主要研究者已经证明，分离的和成对的Al位点在使用铜（Cu）交换的钙辉石沸石选择性催化还原（SCR） NOx中起重要作用。本研究将建立一系列沸石的合成凝胶电荷密度与配对Al密度之间的预测关系，建立Cu沸石中框架Al分布与框架外Cu分布之间的关系，并确定其在NOx SCR反应中的动力学和机理作用。在先前合作研究的基础上，PI将利用表征工具，提供质子和金属交换沸石上总酸位点和配对酸位点的快速定量，从而促进合成-结构-功能关系的发展，可用于定制一系列应用的沸石。

Abstract (Gounder; 1552517)This study will develop new synthesis strategies to control the distribution of aluminum (Al) active sites in zeolite catalysts used for nitrogen oxides (NOx) abatement and carbon feedstock conversion to fuels and chemicals. Tailoring active site proximity and distribution in zeolites will open new opportunities for catalytic innovation in both the environmental protection and carbon conversion areas, while also providing new insight into the chemistry of zeolite crystallization. The research will be linked with educational and mentoring initiatives in the STEM areas for students at all levels.Currently, there is little understanding of the relationships between the atomic arrangement of Al atoms in zeolites and the chemistry of the precursor solutions and gels used to synthesize them. This work is based on the hypothesis that the distribution of catalytically-relevant isolated and paired Al sites in zeolites can be controlled by the charge density of the synthesis gel. Isolated and paired Al sites have been shown by the principal investigator to play important roles in the selective catalytic reduction (SCR) of NOx using copper (Cu)-exchanged chabazite zeolites. The present study will develop predictive relations between synthesis gel charge density and paired Al density for a range of zeolites, establish relationships between the framework Al distribution and extraframework Cu distribution in Cu-zeolites, and determine their kinetic and mechanistic roles in the NOx SCR reaction. Building on prior collaborative research, the PI will utilize characterization tools that provide rapid quantification of the numbers of total and paired acid sites on proton- and metal-exchanged zeolites, thereby facilitating the development of synthesis-structure-function relationships that can be used to tailor zeolites for a range of applications.