Rao Zhiqiang, Wang Kaiwen, Cao Yuehan, Feng Yibo, Huang Zeai, Chen Yaolin, Wei Shiqian, Liu Luyu, Gong Zhongmiao, Cui Yi, Li Lina, Tu Xin, Ma Ding, Zhou Ying
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, People's Republic of China.
School of New Energy and Materials, Southwest Petroleum University, Chengdu 610500, People's Republic of China.
J Am Chem Soc. 2023 Oct 4. doi: 10.1021/jacs.3c07077.
Dry reforming of methane (DRM) has been investigated for more than a century; the paramount stumbling block in its industrial application is the inevitable sintering of catalysts and excessive carbon emissions at high temperatures. However, the low-temperature DRM process still suffered from poor reactivity and severe catalyst deactivation from coking. Herein, we proposed a concept that highly durable DRM could be achieved at low temperatures via fabricating the active site integration with light irradiation. The active sites with Ni-O coordination (Ni/CeO) and Ni-Ni coordination (Ni/CeO) on CeO, respectively, were successfully constructed to obtain two targeted reaction paths that produced the key intermediate (CHO*) for anticoking during DRM. In particular, the diffuse reflectance infrared Fourier transform spectroscopy coupling with steady-state isotopic transient kinetic analysis ( DRIFTS-SSITKA) was utilized and successfully tracked the anticoking paths during the DRM process. It was found that the path from CH* to CHO* over Ni/CeO was the key path for anticoking. Furthermore, the targeted reaction path from CH* to CHO* was reinforced by light irradiation during the DRM process. Hence, the Ni/CeO catalyst exhibits excellent stability with negligible carbon deposition for 230 h under thermo-photo catalytic DRM at a low temperature of 472 °C, while Ni/CeO shows apparent coke deposition behavior after 0.5 h in solely thermal-driven DRM. The findings are vital as they provide critical insights into the simultaneous achievement of low-temperature and anticoking DRM process through distinguishing and directionally regulating the key intermediate species.
甲烷干重整（DRM）已被研究了一个多世纪；其工业应用中的主要绊脚石是催化剂不可避免的烧结以及高温下过多的碳排放。然而，低温DRM过程仍然存在反应活性差和因结焦导致催化剂严重失活的问题。在此，我们提出了一个概念，即通过将活性位点与光辐照相结合，可以在低温下实现高度耐用的DRM。分别在CeO上成功构建了具有Ni-O配位（Ni/CeO）和Ni-Ni配位（Ni/CeO）的活性位点，以获得两条产生DRM过程中抗结焦关键中间体（CHO*）的目标反应路径。特别是，利用漫反射红外傅里叶变换光谱与稳态同位素瞬变动力学分析联用技术（DRIFTS-SSITKA）成功追踪了DRM过程中的抗结焦路径。发现Ni/CeO上从CH到CHO的路径是抗结焦的关键路径。此外，在DRM过程中，光辐照增强了从CH到CHO的目标反应路径。因此，在472℃的低温热光催化DRM条件下，Ni/CeO催化剂表现出优异的稳定性，230小时内碳沉积可忽略不计，而在单纯热驱动的DRM中，Ni/CeO在0.5小时后就出现了明显的积炭行为。这些发现至关重要，因为它们通过区分和定向调控关键中间物种，为同时实现低温和抗结焦的DRM过程提供了关键见解。
