INFEWS N/P/H2O: Collaborative Research: Catalytic Dephosphorylation Using Ceria Nanocrystals

磷(P)是维持生命的重要元素，在农业中具有重要的经济意义。然而，目前的磷肥生产依赖于消耗有限的原料，如磷矿。在化学部化学催化项目的资助下，约翰霍普金斯大学的王超博士和路易斯安那州立大学的许晔博士正在合作开发一种被称为多相催化剂的化学物质，这种化学物质可以促进可再生生物质中磷的去除，从而产生可用于合成肥料的磷。在王超博士的团队中，先进的合成技术，x射线和分子光谱表征以及催化研究相结合，探索基于稀土氧化物“纳米晶体”的新型去磷酸化催化剂，其尺寸约为0.00000005英寸。与此同时，叶旭博士的团队利用密度泛函理论（DFT）为这些催化剂创建了原子尺度的理论模型，以计算控制反应速率和能量消耗的反应途径和障碍。去除磷的过程。实验和理论方法相结合，发展催化机制的基本认识。王博士和徐博士都积极参与推广科学、技术、工程和数学（STEM）学科的教育项目。这些调查人员在他们的研究中纳入了本科生，并参与了与当地学校的联系。王教授一直积极参与巴尔的摩小学（SABES）项目的STEM成就计划，以及巴尔的摩的其他学校，以及该大学的女性科学与工程（WISE）计划。许教授与路易斯安那州科学与工程公平竞赛和当地学校合作。本研究开发了创新和可再生的磷(P)生产方法。这一点很重要，因为磷是维持生命的关键元素，被广泛用于对现代农业实践至关重要的肥料生产。为了应对这一挑战，约翰霍普金斯大学的王超博士和路易斯安那州立大学的许晔博士正在合作探索使用二氧化铈纳米晶体催化去磷酸化。本项目通过整合先进的纳米材料合成、x射线和分子光谱表征、催化研究和密度泛函理论（DFT）计算，识别出重要的二氧化铈表面结构，如晶面和缺陷（铈阳离子（Ce3+）和氧空位），并对其进行系统评价，以建立结构-性能关系并确定活性位点。首先以对硝基苯基磷酸（p-NPP）和磷酸单甲基磷酸（MP）作为模型分子进行反应动力学的综合研究，然后将研究推广到各种类型的磷酸酯分子，包括芳基磷酸盐和烷基磷酸盐、核苷酸和磷脂。该研究能够有效地从生物质中回收磷，用于磷的可再生生产。这些磷可以用于生产经济高效农业所必需的肥料。这项工作获得了关于二氧化铈催化剂的结构-性能关系的新的基础知识，特别是在纳米尺度和水溶液环境下。两位研究人员积极参与推广科学、技术、工程和数学（STEM）学科的教育项目。这些活动包括培养研究生最先进的实验和理论技能，培养他们独立的研究理念，为本科生提供科学和工程研究前沿的实践经验，并吸引来自不同背景的初高中学生作为暑期实习生在研究人员的实验室工作。

Phosphorus (P) is a crucial element for sustaining life and is economically important in agriculture. The current production of P fertilizers, however, relies on depleting limited feedstocks such as phosphate rocks. With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. Chao Wang from Johns Hopkins University and Dr. Ye Xu from Louisiana State University are collaborating to develop chemicals, known as heterogeneous catalysts, which promote the removal f phosphorus of renewable biomass to produce phosphorous which can be used to synthesize fertilizers. In Dr. Chao Wang's group, advanced synthesis techniques, X-ray and molecular spectroscopic characterization, and catalytic studies are combined to explore novel dephosphorylation catalysts based on rare-earth oxide "nanocrystals" whose dimensions are on the order of 0.00000005 inches. Meanwhile, Dr. Ye Xu's group creates atomic -scale theoretical models for these catalysts using density function theory (DFT) to calculate the reaction pathways and barriers that control the reaction rates and energy consumption. of the phosphorus removal processes. The experimental and theoretical approaches are integrated to develop fundamental understanding of the catalytic mechanisms. Both Dr. Wang and Dr. Xu are actively engaged in outreach programs for promotion of education in the science, technology, engineering and mathematics (STEM) disciplines. These investigators have incorporated undergraduate students in their research and are involved in outreach with local schools. Professor Wang has been active through a STEM Achievement program in Baltimore Elementary Schools (SABES) project and with other schools in Baltimore in addition to the Woman in Science and Engineering (WISE) program at the university. Professor Xu works with the Louisiana State Science and Engineering Fair competition and local schools. This research develops innovative and renewable methods for phosphorus (P) production. This is important because phosphorous is a crucial element for sustaining life and is widely employed in fertilizer production crucial to modern agricultural practices. To tackle this challenge, Dr. Chao Wang from Johns Hopkins University and Dr. Ye Xu from Louisiana State University are collaborating to explore catalytic dephosphorylation using ceria nanocrystals. By integration of advanced nanomaterial synthesis, X-ray and molecular spectroscopic characterization, catalytic studies and density functional theory (DFT) calculations, the project identifies the important ceria surface structures, such as crystal facets and defects (cerium cation (Ce3+) and oxygen vacancies), and systematically evaluates them to establish the structure-property relationships and identify the active sites. Para-nitrophenyl phosphate (p-NPP) and monomethyl phosphate (MP) are first used as model molecules to perform comprehensive studies of the reaction kinetics, and the studies are then generalized to various types of phosphate ester molecules, including aryl and alkyl phosphates, nucleotides and phospholipids. The research enables the efficient recovery of phosphorus from biomass for the renewable production of phosphorus. This phosphorus can then be used in the production of fertilizers that are necessary for economical and productive agriculture. This work gains new, fundamental knowledge about the structure-property relationships of the ceria catalysts, particularly at the nanoscale and in aqueous solution environment. The two investigators are actively engaged in outreach programs for promotion of education in the science, technology, engineering and mathematics (STEM) disciplines. These activities include training graduate students with state-of-the-art experimental and theoretical skills and developing their independent research philosophy, providing undergraduate students with hands-on experiences at the cutting edge of science and engineering research, and engaging middle- and high-school students from diverse backgrounds to work in the investigators' laboratories as summer interns.