Empowering catalyst supports: a new concept for catalyst design demonstrated in the Fischer-Tropsch synthesis

DOI: 10.1021/acscatal.3c00924

Authors: Motlokoa Khasu (University of Cape Town) , Wijnand Marquart (University of Cape Town) , Patricia J. Kooyman (University of Cape Town) , Charalampos Drivas (HarwellXPS, Research Complex at Harwell; University of Manchester) , Mark Isaacs (Research Complex at Harwell; University College London; University College London) , Alexander J. Mayer (Loughborough University) , Sandie E. Dann (Loughborough University) , Simon Kondrat (Loughborough University) , Michael Claeys (University of Cape Town) , Nico Fischer (University of Cape Town)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Catalysis , VOL 1 , PAGES 6862 - 6872

State: Published (Approved)
Published: May 2023
Diamond Proposal Number(s): 19850

Abstract: The Fischer–Tropsch (FT) synthesis is traditionally associated with fossil fuel consumption, but recently this technology has emerged as a keystone that enables the conversion of captured CO2 with sustainable hydrogen to energy-dense fuels and chemicals for sectors which are challenging to be electrified. Iron-based FT catalysts are promoted with alkali and transition metals to improve reducibility, activity, and selectivity. Due to their low concentration and the metastable state under reaction conditions, the exact speciation and location of these promoters remain poorly understood. We now show that the selectivity promoters such as potassium and manganese, locked into an oxidic matrix doubling as a catalyst support, surpass conventional promoting effects. La1–xKxAl1–yMnyO3−δ (x = 0 or 0.1; y = 0, 0.2, 0.6, or 1) perovskite supports yield a 60% increase in CO conversion comparable to conventional promotion but show reduced CO2 and overall C1 selectivity. The presented approach to promotion seems to decouple the enhancement of the FT and the water–gas shift reaction. We introduce a general catalyst design principle that can be extended to other key catalytic processes relying on alkali and transition metal promotion.

Journal Keywords: iron-based Fischer−Tropsch synthesis; potassium promotion; manganese promotion; perovskite supports; novel promoter delivery

Subject Areas: Chemistry, Materials


Instruments: B18-Core EXAFS

Added On: 08/05/2023 08:56

Documents:
acscatal.3c00924.pdf

Discipline Tags:

Physical Chemistry Catalysis Chemistry Materials Science Perovskites Metallurgy

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS)