天津大学巩金龙团队报道了串联丙烷脱氢和表面氧化的催化剂选择性合成丙烯。相关研究成果发表在2023年7月27日出版的《科学》。

丙烷直接脱氢（PDH）制备丙烯是一种理想的商业反应，但它是高度吸热的，并且受到热力学平衡的严重限制。将氢作为水氧化去除的氧化途径具有安全性和成本挑战。

该文中，研究人员将化学循环选择性H₂燃烧和PDH与多功能FeVO₄-VO_x氧化还原催化剂相结合。负载在Al₂O₃上的分散良好的VOx提供脱氢位点，并且相邻的纳米级FeVO₄充当后续H₂燃烧的氧载体。在550°C下，在42.7%的丙烷转化率下，研究人员实现了81.3%的丙烯选择性的整体性能，用于再氧化FeVO₄的200个化学循环。

基于催化实验、光谱表征和理论计算，研究人员提出了一种氢溢出介导的耦合机制。在VO_x位点产生的氢物种迁移到相邻的FeVO₄进行燃烧，从而使PDH向丙烯转移。催化位点和燃烧位点之间的接近有利于这种机制。

附：英文原文

Title: Tandem propane dehydrogenation and surface oxidation catalysts for selective propylene synthesis

Author: Wei Wang, Sai Chen, Chunlei Pei, Ran Luo, Jiachen Sun, Hongbo Song, Guodong Sun, Xianhui Wang, Zhi-Jian Zhao, Jinlong Gong

Issue&Volume: 2023-07-27

Abstract: Direct propane dehydrogenation (PDH) to propylene is a desirable commercial reaction but is highly endothermic and severely limited by thermodynamic equilibrium. Oxidative routes that oxidatively remove hydrogen as water have safety and cost challenges. We couple chemical looping selective H2 combustion and PDH with multifunctional FeVO4-VOx redox catalysts. Well-dispersed VOx supported on Al2O3 provides dehydrogenation sites, and adjacent nanoscale FeVO4 acts as oxygen carriers for subsequent H2 combustion. We achieve an integral performance of 81.3% propylene selectivity at 42.7% propane conversion at 550°C for 200 chemical looping cycles for re-oxidizing FeVO4. Based on catalytic experiments, spectroscopic characterization, and theory calculations, we propose a hydrogen spillover-mediated coupling mechanism. The hydrogen species generated at the VOx sites migrated to adjacent FeVO4 for combustion, which shifted PDH toward propylene. This mechanism is favored by the proximity between catalytic and combustion sites.

DOI: adi3416

Source: https://www.science.org/doi/full/10.1126/science.adi3416