美国马里兰大学Hu Liangbing开发了高效热化学合成的可编程加热和淬火策略。相关研究成果于2022年5月18日发表在《自然》。
由于缺乏对反应温度和时间以及反应路径的时间控制，在近平衡条件下通过连续加热进行的常规热化学合成在提高合成速率、选择性、催化剂稳定性和能效方面面临着严峻挑战。作为替代方案，研究人员提出了一种非平衡连续合成技术，该技术使用脉冲加热和淬火（例如，0.02s打开，1.08s关闭），使用可编程电流快速切换高温（例如，高达2400K）和低温之间的反应。快速淬火确保了高选择性和良好的催化剂稳定性，并降低了平均温度以降低能源成本。
以CH4热解为模型反应，该可编程加热和淬火技术对增值C2产品具有高选择性（传统非催化方法的选择性大于75%，而传统方法的选择性小于35%，而使用优化催化剂的大多数传统方法的选择性小于60%）。
该技术可以扩展到一系列热化学反应，例如NH3合成，为此，研究人员使用未优化的催化剂，在环境压力下，在100小时以上的时间内，实现了约6000μmolgFe1h-1的稳定和高合成速率。该研究建立了一个高效非平衡热化学合成的新模型。
附：英文原文
Title: Programmable heating and quenching for efficient thermochemical synthesis
Author: Dong, Qi, Yao, Yonggang, Cheng, Sichao, Alexopoulos, Konstantinos, Gao, Jinlong, Srinivas, Sanjana, Wang, Yifan, Pei, Yong, Zheng, Chaolun, Brozena, Alexandra H., Zhao, Hao, Wang, Xizheng, Toraman, Hilal Ezgi, Yang, Bao, Kevrekidis, Ioannis G., Ju, Yiguang, Vlachos, Dionisios G., Liu, Dongxia, Hu, Liangbing
Issue&Volume: 2022-05-18
Abstract: Conventional thermochemical syntheses by continuous heating under near-equilibrium conditions face critical challenges in improving the synthesis rate, selectivity, catalyst stability and energy efficiency, owing to the lack of temporal control over the reaction temperature and time, and thus the reaction pathways1,2,3. As an alternative, we present a non-equilibrium, continuous synthesis technique that uses pulsed heating and quenching (for example, 0.02s on, 1.08s off) using a programmable electric current to rapidly switch the reaction between high (for example, up to 2,400K) and low temperatures. The rapid quenching ensures high selectivity and good catalyst stability, as well as lowers the average temperature to reduce the energy cost. Using CH4 pyrolysis as a model reaction, our programmable heating and quenching technique leads to high selectivity to value-added C2 products (>75% versus <35% by the conventional non-catalytic method and versus <60% by most conventional methods using optimized catalysts). Our technique can be extended to a range of thermochemical reactions, such as NH3 synthesis, for which we achieve a stable and high synthesis rate of about 6,000μmolgFe1h1 at ambient pressure for >100h using a non-optimized catalyst. This study establishes a new model towards highly efficient non-equilibrium thermochemical synthesis.
DOI: 10.1038/s41586-022-04568-6
Source: https://www.nature.com/articles/s41586-022-04568-6