Semiconductor/Mixed-Conducting-Oxide Heterojunction for Photo-electrochemical H2O & CO2 Splitting at Elevated Temperatures

用于光电化学 H2O 的半导体/混合导电氧化物异质结

• 批准号: 1336835
• 负责人: William Chueh
• 金额: $ 25万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1336835&HistoricalAwards=false
• 关键词: Semiconductor; Mixed; Conducting; Oxide; Heterojunction

PI: Chueh, WilliamProposal Number: 1336835Institution: Stanford UniversityTitle: Semiconductor/Mixed-Conducting-Oxide Heterojunction for Photo-electrochemical H2O and CO2 Splitting at Elevated TemperaturesMaking solar energy available when and where it is required is crucial towards increasing its utilization. Dissociating steam and/or carbon dioxide to chemical fuels is a promising route for storing solar energy. The objective of this work is to design a new class of photo-electrochemical cells that operates at 500 to 700 deg. C rather than at room temperature by utilizing an all solid-state design. Using an oxide heterojunction consisting of a semiconducting light absorber and a mixed oxygen ion and electron conducting oxide, incident solar energy above and below the band gap of the light absorber is converted to thermal energy, which in turn increases the solar-to-fuel efficiency. Unlike conventional photovoltaic-based approaches, here the solar-to-fuel efficiency increases, rather than decreases, with temperature. Thin-film heterojunctions consisting of oxides such as iron, vanadium, and titanium oxides will be evaluated for their potential in elevated temperature photo-electrochemical water and carbon dioxide splitting. The specific objective is to identify a combination of materials that delivers high solar-to-fuel efficiency and reliability over thousands of hours.The central component of this research is understanding and controlling charge generation, separation, and recombination at the heterojunction between a semiconducting oxide and a mixed ionic and electronic conducting oxide, at temperatures significantly above ambient. In photo-electrochemistry involving oxides, ionic defects such as vacancies must play an important role, yet it is not well understood. By combining rapid material screening, opto-electrochemical and in-situ synchrotron X-ray characterizations of oxide heterojunctions, this research aims to understand the interfacial chemistry and electronic properties at the junction of dissimilar solids under extreme conditions.This research seeks to enhance the viability of storing intermittent solar energy in chemical bonds, and increase the global utilization of solar energy. Beyond energy generation and storage, advanced understanding of charge transport at heterojunctions will benefit scientific fields such as catalysis and high temperature electronics, and applications such as solid-oxide fuel cells and sensors in extreme environments. The project work also provides research opportunities for one graduate student over the duration of the project. In addition to incorporating the results into undergraduate and graduate curriculums, the PI will develop a unique "Solar After Dark" outreach program. Human interaction with sunlight is one of the most ubiquitous phenomena in daily life and is an excellent vehicle to raise student interest in science and engineering.

主要研究者：Chueh，William提案编号：1336835机构：斯坦福大学标题：半导体/混合导电氧化物异质结光电化学H2O和CO2分裂在高温下使太阳能在需要的时候和地方是至关重要的，以提高其利用率。将蒸汽和/或二氧化碳分解为化学燃料是储存太阳能的一种有前途的途径。这项工作的目的是设计一种新型的光电化学电池，工作在500至700度。C，而不是在室温下，通过利用全固态设计。使用由半导体光吸收剂和混合的氧离子和电子传导氧化物组成的氧化物异质结，光吸收剂的带隙之上和之下的入射太阳能被转换成热能，这又增加了太阳能-燃料效率。与传统的基于光电转换的方法不同，这里的太阳能-燃料效率随着温度的增加而增加，而不是减少。由铁、钒和钛氧化物等氧化物组成的薄膜异质结将评估其在高温光电化学水和二氧化碳裂解中的潜力。具体目标是确定一种材料的组合，提供高的太阳能-燃料效率和可靠性超过数千小时。这项研究的核心组成部分是理解和控制电荷的产生，分离，和复合之间的异质结半导体氧化物和混合离子和电子导电氧化物，在温度显着高于环境。在涉及氧化物的光电化学中，离子缺陷（如空位）一定起着重要的作用，但人们对它的认识还不很清楚。本研究结合快速材料筛选、光电化学和同步辐射X射线原位表征氧化物异质结，旨在了解极端条件下异质固体结的界面化学和电子性质，旨在提高以化学键储存间歇性太阳能的可行性，提高太阳能的全球利用率。 除了能量产生和存储，对异质结电荷传输的深入了解将有利于催化和高温电子等科学领域，以及极端环境中的固体氧化物燃料电池和传感器等应用。该项目工作还提供了一个研究生在项目期间的研究机会。除了将结果纳入本科生和研究生课程外，PI还将开发一个独特的“天黑后的太阳能”推广计划。人类与阳光的互动是日常生活中最普遍的现象之一，也是提高学生对科学和工程兴趣的绝佳工具。