UNS:Collaborative Research: Atomistic Design of High-Performance Epoxidation Catalysts with Atomic Layer Deposition and Kinetic Monte Carlo Simulations

将丙烯直接氧化为环氧丙烷代表了一种具有更可持续生产能力的分子的巨大潜力，目前这种分子的年产量为90亿磅。目前的生产本身效率低下，使用大量的能源，产生大量的浪费。这项工作提出了新的催化剂组合物和高度工程化的结构，有可能促进分子氧的直接氧化，提高选择性和转化率，减少能源消耗和环境浪费。研究人员假设通过精心合成钯金和银金双金属纳米催化剂可以提高丙烯选择性氧化的稳定性、选择性和效率。新的催化剂有望受益于Au的高选择性和附加第二金属的高活性。金纳米团簇表面用钯或银原子修饰，得到的粒子彼此隔离，并通过粒子之间金属氧化物丘的沉积优化了与钛硅石载体的相互作用。胶体合成和原子层沉积（ALD）的结合将用于创建高度工程化的结构。同步加速器x射线吸收精细结构（XAFS）光谱和原子尺度动力学蒙特卡罗（KMC）计算将用于潜在地揭示工作催化剂的动态图像，并精确地确定第二种金属的机制作用。如果成功，这些催化剂可能会改变环氧丙烷行业的游戏规则。此外，该研究将为这种类型的双金属催化剂在其他大规模工业化学反应中的潜在作用提供有价值的认识。该研究将通过为阿拉巴马州两所机构的两名研究生和本科生提供支持来实现教育推广。另一个扩展部分是由本科生和研究生的研究人员到亨茨维尔地区的催化剂生产基地和商业研发中心进行实地考察。

1511820(Lei) & 1510485(Turner)Direct oxidation of propylene to propylene oxide represents huge potential for a change to much more sustainable production of a molecule that currently has production levels of 9 billion pounds a year. Current production is inherently inefficient using vast amounts of energy and producing significant waste. This work proposes novel catalyst compositions and highly-engineered structures that have the potential to promote the direct oxidation with molecular oxygen at improved selectivity and conversion, and with less energy consumption and environmental waste.The PIs hypothesize that the stability, selectivity, and efficiency of propylene selective oxidation can be improved by carefully synthesizing Pd-Au and Ag-Au bimetallic nano-catalysts. The new catalysts are expected to benefit from the high selectivity of Au and the high activity of the additional second metal. Au nanoclusters are decorated with surface atoms of Pd or Ag, and the resultant particles are isolated from one another and optimized for interaction with a titanium-silicalite support by the deposition of metal oxide hillocks between the particles. The combination of colloidal synthesis and atomic layer deposition (ALD) will be used to create the highly-engineered structures. Synchrotron X-ray absorption fine structure (XAFS) spectroscopy, and atomic-scale kinetic Monte Carlo (KMC) calculations will be employed to potentially reveal a dynamic picture of the working catalysts and precisely identify the mechanistic role of the second metal. If successful, these catalysts could be a a game-changer for the propylene oxide industry. In addition the study will provide valuable understanding of the potential role of bimetaliic catalysts of this type for other large-scale industrial chemical reactions. The study will achieve educational outreach by providing support to two graduate students and also undergraduate students at two institutions within the state of Alabama. Another outreach component is field trips by both undergraduate and graduate researchers to catalyst manufacturing sites and commercial R&D centers in the Huntsville area.