丹麦技术大学Ib Chorkendorff团队报道了自旋介导的Co催化剂对氨合成的促进作用。相关研究成果于2024年3月22日发表于国际一流学术期刊《科学》。

在过去的二十年里，人们对开发催化剂越来越感兴趣，以使Haber Bosch氨合成能够在比目前更温和的条件下进行。合理的催化剂设计需要理论指导和明确的机理理解。

最近，提出了一种自旋介导的促进机制，通过引入结合到催化剂表面活性位点的杂金属原子来活化传统上不活泼的磁性材料，如钴（Co），用于氨合成。研究人员将理论和实验相结合，在镧（La）/Co体系上验证了这种促进机制。通过在环境压力下对Co单晶和质量选择的Co纳米颗粒进行模型催化剂研究，确定氨合成的活性位点为具有La吸附的Co步骤的B5位点。在350°C和1bar的条件下，La/Co系统实现的每秒0.47±0.03的周转频率，超过了在相同条件下测试的其他模型催化剂。

附：英文原文

Title: Spin-mediated promotion of Co catalysts for ammonia synthesis

Author: Ke Zhang, Ang Cao, Lau Halkier Wandall, Jerome Vernieres, Jakob Kibsgaard, Jens K. Nrskov, Ib Chorkendorff

Issue&Volume: 2024-03-22

Abstract: Over the past two decades, there has been growing interest in developing catalysts to enable Haber-Bosch ammonia synthesis under milder conditions than currently pertain. Rational catalyst design requires theoretical guidance and clear mechanistic understanding. Recently, a spin-mediated promotion mechanism was proposed to activate traditionally unreactive magnetic materials such as cobalt (Co) for ammonia synthesis by introducing hetero metal atoms bound to the active site of the catalyst surface. We combined theory and experiment to validate this promotion mechanism on a lanthanum (La)/Co system. By conducting model catalyst studies on Co single crystals and mass-selected Co nanoparticles at ambient pressure, we identified the active site for ammonia synthesis as the B5 site of Co steps with La adsorption. The turnover frequency of 0.47 ± 0.03 per second achieved on the La/Co system at 350°C and 1 bar surpasses those of other model catalysts tested under identical conditions.

DOI: adn0558

Source: https://www.science.org/doi/10.1126/science.adn0558