Collaborative Research: Design of a Novel Photo-Thermo-Catalyst for Enhanced Activity and Stability of Dry Reforming of Methane

含有甲烷（CH 4）和二氧化碳（CO2）的废气来自页岩油回收、垃圾填埋场、家禽和牲畜养殖场以及其他沼气来源。 升级这些气体的一种方法是在催化剂存在下使它们反应，将它们转化为简单的气体，如一氧化碳（CO）和氢气（H2），这些气体可以进一步加工成各种化学品和燃料。 甲烷和二氧化碳之间的催化反应需要极高的温度，这使得它从能量消耗的角度来看没有吸引力。 另一种方法是利用直接的阳光照射和通过太阳能收集器产生的热量的组合，以在仅由太阳能驱动的可持续过程中通过同时的光催化和热催化使气体反应。 该项目使用一种名为甲烷热光催化干重整（DRM）的新方法来探索这一概念。 具体而言，该项目将侧重于将联合收割机直接燃烧与热催化相结合的催化剂设计，以在比仅基于传统化石燃料热催化的温度低得多的温度下实现稳定、高效的DRM。 该技术可以在可持续地满足我们国家未来的能源需求方面发挥重要作用，同时将温室气体-CH 4和CO2 -转化为有用的燃料和化学品。该项目将研究热光催化DRM的几个新方面，包括：（1）制造新型和稳定的催化剂，其通过整合光催化活性载体促进光催化和热催化效应之间的协同作用，（2）设计创新的纳米结构，即通过原子层沉积（ALD）在催化剂上的多孔外涂层，以减轻金属烧结并防止焦炭形成;（3）通过原位DRIFTS的组合，理解高温下光热催化的基本机理。（漫反射FTIR）光谱、催化剂活性的GC/MS测量以及使用同位素标记的CO2和CH 4分子的实验;和（4）通过利用原位X射线散射，X射线衍射，和X射线吸收光谱学在先进的光子源的阿贡国家实验室。这项研究将推进在多相催化，表面化学，纳米科学和光谱学的跨学科领域的基本理解。 除了研究的技术部分，该项目将得到两个机构的几个项目的支持，旨在为高中学生和他们的教师提供发展研究技能的机会。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Waste gases containing methane (CH4) and carbon dioxide (CO2) are produced from sources such as shale oil recovery, landfills, poultry and livestock farms, and other biogas sources. One way to upgrade those gases is to react them in the presence of catalysts to transform them into simple gases such as carbon monoxide (CO) and hydrogen (H2) that can be further processed to a wide range of chemicals and fuels. The catalyzed reaction between methane and carbon dioxide requires extremely high temperatures which makes it unattractive from an energy consumption standpoint. An alternative approach is to utilize a combination of direct sunlight irradiation and heat generated via solar energy collectors to react the gases via simultaneous photocatalysis and thermal catalysis in a sustainable process driven solely by the sun's energy. The project explores that concept using a novel approach known as thermo-photo-catalytic dry reforming of methane (DRM). Specifically, the project will focus on catalyst designs that combine direct photocatalysis with thermal catalysis to achieve stable, highly-efficient DRM at temperatures much lower than those based on conventional fossil-fuel thermal catalysis alone. The technology can potentially play a significant role in sustainably meeting our nation's future energy needs while simultaneously transforming the greenhouse gases - CH4 and CO2 - to useful fuels and chemicals.The project will investigate several novel aspects of thermo-photo-catalytic DRM, including: (1) fabricating novel and stable catalysts that promote synergy between the photo- and thermo-catalytic effects via integration of a photocatalytically active support, inexpensive metal nanocatalysts dispersed on the support, and promoters to enhance catalytic activity and stability; (2) designing innovative nanostructures, i.e. an ultrathin porous overcoat on the catalyst via atomic layer deposition (ALD) to mitigate metal sintering and prevent coke formation; (3) understanding the fundamental mechanism of photo-thermo-catalysis at elevated temperatures through a combination of in situ DRIFTS (diffuse reflectance FTIR) spectroscopy, GC/MS measurement of the catalyst activity, and experiments using isotopically labeled CO2 and CH4 molecules; and (4) elucidating catalyst structure-activity-stability relationships through operando studies of metal valence, nanoparticle size, and overcoat pore structure changes, carried out utilizing in situ X-ray scattering, X-ray diffraction, and X-ray absorption spectroscopy at the Advanced Photon Source of Argonne National Laboratory. This research will advance fundamental understanding in the interdisciplinary areas of heterogeneous catalysis, surface chemistry, nanoscience, and spectroscopy. In addition to the technical component of the research, the project will be supported by several programs at both institutions aimed at providing both high-school students and their teachers opportunities to develop research skills.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.