Lin Le, Sun Xiaoyuan, Jia Haoran, Feng Xiaohui, Wang Yingjie, Mu Rentao, Fu Qiang, Bao Xinhe
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Interdisciplinary Research Center for Biology and Chemistry, Liaoning Normal University, Dalian 116029, China.
Precis Chem. 2025 May 30;3(9):525-534. doi: 10.1021/prechem.5c00022. eCollection 2025 Sep 22.
ZnZrO is a promising oxide component for direct syngas conversion via oxide-zeolite bifunctional catalysis, while rational design of active centers within the composite oxide remains limited. In this study, through ab initio thermodynamics, molecular dynamics, and microkinetic modeling, we find that diverse subnanometer ZnO species, including single-site, single-chain, and single-layer configurations, can form on active ZrO surfaces under the reaction conditions. These confined ZnO species weaken CO adsorption but enhance heterolytic H dissociative adsorption, favoring continuous hydrogenation of CO to methanol over direct or H-assisted CO dissociation. For single-layer ZnO structures, a double-chain film grows on a monoclinic ZrO (m-ZrO) surface while a graphene-like film emerges on tetragonal ZrO (t-ZrO). These single-layer ZnO species exhibit higher methanol formation activity than their single-chain or single-site counterparts, which benefit from sufficient sites for adsorption of intermediates and a suitable space for bonding of H with C in CHO. Furthermore, the double-chain ZnO film confined on m-ZrO exposes octahedral Zn sites, which are more reactive than the triangular Zn sites in the graphene-like ZnO on t-ZrO, despite both sites being nominally three-coordinate. These findings provide insights for the precise design of composite oxide/oxide catalysts through fine-tuning overlayer coverage and/or support surface properties.
ZnZrO是一种通过氧化物-沸石双功能催化直接转化合成气的有前景的氧化物组分，而复合氧化物中活性中心的合理设计仍然有限。在本研究中，通过从头算热力学、分子动力学和微观动力学建模，我们发现，在反应条件下，活性ZrO表面可形成多种亚纳米级ZnO物种，包括单中心、单链和单层构型。这些受限的ZnO物种减弱了CO的吸附，但增强了异裂H解离吸附，有利于CO连续氢化为甲醇，而不是直接或H辅助的CO解离。对于单层ZnO结构，在单斜ZrO（m-ZrO）表面生长出双链薄膜，而在四方ZrO（t-ZrO）表面出现类似石墨烯的薄膜。这些单层ZnO物种表现出比其单链或单中心对应物更高的甲醇生成活性，这得益于有足够的位点吸附中间体以及有合适的空间使H与CHO中的C结合。此外，限制在m-ZrO上的双链ZnO薄膜暴露了八面体Zn位点，尽管这两个位点名义上都是三配位的，但这些位点比t-ZrO上类似石墨烯的ZnO中的三角形Zn位点更具反应活性。这些发现为通过微调覆盖层覆盖率和/或载体表面性质来精确设计复合氧化物/氧化物催化剂提供了见解。
