Work

Harnessing inactive molybdenum species in ill-defined catalyst to work in propylene metathesis by propane pretreatment

Year: 2025

Type: article

Abstract: Rising imbalance in olefins demand and searching for more selective way of olefins production leads to increase importance of the on-purpose technologies. A special role plays olefin metathesis that (due to its reversibility) can be used as a switching reaction for compensation imbalance between produced olefins in the large-scale petrochemical processes. In this work a simple and effective procedure for generation of active in olefin metathesis sites over molybdenum oxide catalysts containing between 1 to 20 wt% of MoO 3 prepared by a simple incipient wetness impregnation of silica has been investigated. Compared with inert gas pretreatment a significant improvement (1–2 orders of magnitude) in propylene metathesis activity at 50 °C was achieved after pretreatment in propane between 550 to 650 °C. Physicochemical studies of the catalysts before and after the processes, in-situ UV–Vis analysis during activation, and temperature-programmed surface reaction studies allowed the identification of two distinct stages (clearly visible above 550 °C) during catalyst heating in a propane stream. In the first stage, partial reduction of Mo(VI) occurs simultaneously with the formation of propane reduction products, and as the reduction progresses, propylene is formed through propane dehydrogenation. The second stage, propylene aromatization, takes place on a deeply reduced catalyst. The metathesis activity increases significantly during the reduction stage, reaching its maximum value precisely when the aromatization stage begins. Possible pathways of Mo active sites generation at high temperature in the presence of propane were proposed based on temperature-programmed surface reactions and DFT calculations.

Source: Chemical Engineering Journal

DOI: 10.1016/j.cej.2025.171753

Authors: Mariya Myradova, Jarosław Handzlik, Anna Rokicińska, Piotr Kuśtrowski, Alexey Maximenko, Piotr Michorczyk

Institutions: Cracow University of Technology, Jagiellonian University, SOLARIS National Synchrotron Radiation Centre

Language: English

Topic: Catalysis and Oxidation Reactions

Subfield: Catalysis

Field: Chemical Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,830

Funders: European Commission, Narodowe Centrum Nauki, Horizon 2020 Framework Programme