Pullar Robert C, Novais Rui M, Caetano Ana P F, Barreiros Maria Alexandra, Abanades Stéphane, Oliveira Fernando A Costa
Department of Materials and Ceramic Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, Aveiro, Portugal.
Renewable Energy and Energy System Integration Unit, LNEG-Laboratório Nacional de Energia e Geologia I.P., LEN-Laboratório de Energia, Lisbon, Portugal.
Front Chem. 2019 Sep 4;7:601. doi: 10.3389/fchem.2019.00601. eCollection 2019.
This review explores the advances in the synthesis of ceria materials with specific morphologies or porous macro- and microstructures for the solar-driven production of carbon monoxide (CO) from carbon dioxide (CO). As the demand for renewable energy and fuels continues to grow, there is a great deal of interest in solar thermochemical fuel production (STFP), with the use of concentrated solar light to power the splitting of carbon dioxide. This can be achieved in a two-step cycle, involving the reduction of CeO at high temperatures, followed by oxidation at lower temperatures with CO, splitting it to produce CO, driven by concentrated solar radiation obtained with concentrating solar technologies (CST) to provide the high reaction temperatures of typically up to 1,500°C. Since cerium oxide was first explored as a solar-driven redox material in 2006, and to specifically split CO in 2010, there has been an increasing interest in this material. The solar-to-fuel conversion efficiency is influenced by the material composition itself, but also by the material morphology that mostly determines the available surface area for solid/gas reactions (the material oxidation mechanism is mainly governed by surface reaction). The diffusion length and specific surface area affect, respectively, the reduction and oxidation steps. They both depend on the reactive material morphology that also substantially affects the reaction kinetics and heat and mass transport in the material. Accordingly, the main relevant options for materials shaping are summarized. We explore the effects of microstructure and porosity, and the exploitation of designed structures such as fibers, 3-DOM (three-dimensionally ordered macroporous) materials, reticulated and replicated foams, and the new area of biomimetic/biomorphous porous ceria redox materials produced from natural and sustainable templates such as wood or cork, also known as ecoceramics.
本综述探讨了具有特定形态或多孔宏观和微观结构的二氧化铈材料在太阳能驱动下由二氧化碳（CO₂）生产一氧化碳（CO）方面的合成进展。随着对可再生能源和燃料的需求持续增长，人们对太阳能热化学燃料生产（STFP）产生了浓厚兴趣，即利用聚光太阳光为二氧化碳的分解提供动力。这可以通过两步循环实现，包括在高温下还原CeO₂，然后在较低温度下用CO₂氧化，将其分解以产生CO，由聚光太阳能技术（CST）获得的聚光太阳能辐射驱动，以提供通常高达1500°C的高反应温度。自2006年首次将氧化铈作为太阳能驱动的氧化还原材料进行探索，并于2010年专门用于分解CO₂以来，人们对这种材料的兴趣与日俱增。太阳能到燃料的转换效率不仅受材料成分本身的影响，还受材料形态的影响，材料形态主要决定了固/气反应的可用表面积（材料氧化机制主要由表面反应控制）。扩散长度和比表面积分别影响还原和氧化步骤。它们都取决于反应材料的形态，而形态也会极大地影响材料中的反应动力学以及热和质量传输。因此，总结了材料成型的主要相关选择。我们探讨了微观结构和孔隙率的影响，以及对设计结构的利用，如纤维、三维有序大孔（3-DOM）材料、网状和复制泡沫，以及由木材或软木等天然和可持续模板生产的仿生/生物形态多孔二氧化铈氧化还原材料这一新兴领域，也称为生态陶瓷。
