EAGER: Bimetallic nano-structures as versatile photocatalysts

EAGER：利用纳米结构作为高效太阳能驱动化学转化的催化剂用于生产商品化学品的大多数化学转化过程都是完全使用热能进行的，其中美国化学工业消耗的50%的能量需要用于原料，而另外50%提供热能来驱动化学反应和纯化步骤。显然，必须开发在较低温度和较高选择性下操作的化学方法以提高能量和原子（原料转化为产物）效率。这项EAGER奖授予加州大学滨江分校的菲利普克里斯托弗教授，将允许探索一类新材料，这些材料有可能克服热驱动过程的固有限制，并允许在较低温度下进行太阳能辅助化学转化，并具有较高的选择性。这些新的催化剂是采用非常特定的银物质与太阳能和其他金属物质相互作用的混合材料，这将提高反应的选择性。这项研究有可能通过引入新的工艺来产生重大的社会影响，这些工艺开始解决燃烧化石燃料以驱动化学工艺的环境问题。克里斯托弗计划通过动手研究和课堂教育，为不同的观众提供多学科的教育经验。具体来说，与滨江社区学院（RCC）的关系已经发展，这将使学生从这个为期两年的西班牙裔服务机构实习机会在克里斯托弗实验室。这将是一个有益的经验，为RCC学生，以促进他们从社区学院式的教育过渡到一个主要的研究型大学，并激发他们对基础研究的兴趣，从而鼓励他们在教育超越学士学位入学？该项目将对新一代材料的合成和光催化性能进行基础研究，这些材料有可能提高各种工业化学品和燃料生产过程的能源效率和化学选择性。该项目的总体愿景是研究混合材料，利用银与太阳光谱的独特相互作用以及更通用的金属（Pt）的优异催化功能，选择性地利用太阳能驱动重要的化学反应。异质结构的纳米粒子的Ag纳米粒子的核心和Pt壳或沉积粒子组成的将使用种子介导的过程合成。银纳米立方体将通过多元醇工艺合成，Pt将通过在水溶液中还原Pt盐沉积在预合成的银立方体上。关键的合成条件，包括温度，前体注入速率和还原剂强度将被改变，以控制生长机制，并将使用多种方法来表征所得的结构。 将测试纳米结构在CO氧化反应中的活性，作为温度、反应物分压、光照强度和波长的函数。将结果与仅由在绝缘和半导体载体上的Pt和Ag组成的对照催化剂进行比较，以证明Pt/Ag纳米结构的独特性质。这种独特的光催化反应性的展示将为使用太阳能选择性地驱动比当前基于光催化剂的类别可执行的化学反应更广泛的化学反应开辟道路。

EAGER: Utilizing bimetallic nanostructures as catalysts for efficient solar-driven chemical conversionA majority of chemical conversion processes utilized for the production of commodity chemicals are carried out using exclusively thermal energy, where 50% of the energy consumed in the United States chemical industry is required for feedstocks, while the other 50% provides thermal energy to drive chemical reactions and purification steps. It is apparent that chemical processes operating at lower temperature and higher selectivity must be developed to enhance energy and atomic (feed stock conversion to product) efficiencies. This EAGER award made to Professor Phillip Christopher at University of California Riverside will permit a new class of materials to be explored that have the potential to overcome the inherent limitations of thermal driven processes and allow for solar-assisted chemical conversions at lower temperatures and with higher selectivities. These new catalysts are hybrid materials employing very specific silver species for their interactions with solar energy and other metal species which will improve the selectivity for reactions. This research has potential for significant societal impact through the introduction of new processes that begin to address environmental concerns from burning fossil fuels to drive chemical processes. Christopher plans to include multidisciplinary educational experiences for a diverse audience through hands on research and in class education. Specifically, a relationship with Riverside Community College (RCC) has been developed that will give students from this two-year Hispanic Serving Institution internship opportunities in the Christopher laboratories. This will be a useful experience for RCC students to facilitate their transition from a community college style education to a major research University and to spark their interest in basic research, thus encouraging their enrollment in education beyond the Bachelor?s level.This project will undertake basic research into the synthesis and photocatalytic properties of a new generation of materials that have the potential to increase energy efficiency and chemical selectivity for a wide range of industrial chemical and fuel production processes. The overarching vision of this project is to investigate hybrid materials that exploit unique interactions of Ag with the solar spectrum and the excellent catalytic functionality of more versatile metals (Pt) to selectively drive important chemical reactions using solar energy. Hetero-structured bimetallic nanoparticles consisting of Ag nanoparticle cores and Pt shells or deposited particles will be synthesized using a seed mediated process. Ag nanocubes will be synthesized via the polyol process and Pt will be deposited on pre-synthesized Ag cubes by reduction of Pt salts in an aqueous solution. Crucial synthesis conditions including temperature, precursor injection rate and reductant strength will be varied to control the growth mechanism, and the resulting structures will be characterized using numerous methods. Nanostructures will be tested for their activity in the CO oxidation reactions as a function of temperature, reactant partial pressure, illumination intensity and wavelength. The results will be compared to control catalysts consisting only of Pt and Ag on insulating and semiconducting supports to demonstrate unique properties of the bimetallic Pt/Ag nanostructures. The demonstration of unique photocatalytic reactivity of bimetallic plasmonic nanostructures will open avenues towards the use of solar energy to selectively drive a much wider range of chemical reactions than executable on current classes of semiconductor-based photocatalysts.