JACS.中科院大化所刘中民院士、韩晶峰团队：Ga-MFI沸石中Ga(III)/GaHₓ动态互变助力CO₂-环己烷高效耦合制芳烃

摘要：The catalytic coupling conversion of naphtha and CO₂to aromatics over metal-zeolites offers a fascinating route for aromatics prod

摘要

The catalytic coupling conversion of naphtha and CO₂to aromatics over metal-zeolites offers a fascinating route for aromatics production, yet, the exploitation of efficient metal-zeolite catalysts and CO₂coupled naphtha to make CO₂transformed into high-value-added chemicals remain great challenges. Herein, we synthesized a framework-anchored Ga-MFI catalyst synthesizedvialigand-assisted hydrothermal crystallization, achieving 80.76% aromatic selectivity at 99.57% cyclohexane conversion (550 °C, 0.1 MPa, WHSV = 1 h⁻¹) with over 110 h stability for CO₂and cyclohexane (as a model naphthenic compound) coupling reaction. Multimodalin situcharacterization (XAFS, synchrotron XRD, and FTIR) reveals that isolated Ga(III) species undergo reversible coordination switching to GaHₓunder reaction conditions, dynamically mediating CO₂activation through Ga species transfer. Tetrahedrally coordinated Ga-O sites synergize with proximal Brønsted acid sites. Isotopic tracing (¹³CO₂) demonstrates 56.4% of aromatic carbon originates. The catalyst’s self-recovery capability ensures structural integrity and suppresses deactivation. This work establishes a dynamic single-site catalysis framework for a CO₂coupled alkane, advancing the design of zeolite-confined metal catalysts through precise microenvironment engineering.

文章核心要点

在金属-沸石上催化耦合石脑油和CO到芳烃，为芳烃生产提供了一条迷人的途径，然而，开发高效的金属-沸石催化剂和CO₂转化为高附加值化学品仍然是一个巨大的挑战。

要点1.本文通过配体辅助水热结晶合成了一个框架锚定的Ga-MFI催化剂，在99.57%环己烷转化率（550°C，0.1 MPa，WHSV = 1 h⁻¹)下实现了80.76%的芳烃选择性，并且对于CO₂要点2.多模态原位表征（XAFS、同步辐射XRD和FTIR)揭示了在反应条件下，孤立的Ga(III)物种经历可逆的配位切换到GaHx，通过Ga物种的转移动态介导CO₂的活化。四面体配位的Ga-O位点与附近的Bronsted酸位点协同。同位素追踪（¹³₂要点3.这项工作为CO耦合烷烃建立了一个动态的单位点催化框架，通过精确的微环境工程推进了沸石限域金属催化剂的设计。

催化剂结构表征