Organometallic chemistry and heterogeneous catalysis: Sub-nano base metal catalysts.

Lead Research Organisation: Durham University
Department Name: Chemistry

Abstract

Unlike traditional oxide-supported catalysts sub-nano particle materials exploit much bigger metal atom surface area/unit mass ratios and quantum chemical effects to give unique reactivity and electrical character, and so enhanced activity/selectivity. Well-defined sub-nano-size metal particles of base metals Ni, Co, Fe or V immobilised on tuned metal oxide supports will be prepared from tailored organometallic hydrocarbyl complexes, offering particle size control and heteroatom-free particles. DRIFTS, XPS, SEM/TEM, XANES, EXAFS, Raman, NMR, Rutherford backscattering and thermal methods will be used to characterise catalysts. Particle size/activity/selectivity correlation will be made for industry-relevant hydrogenation, dehydrogenation, water gas shift, Fischer Tropsch synthesis reactions.

Publications

10 25 50

Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/R511900/1 30/09/2017 29/09/2022
1929715 Studentship EP/R511900/1 30/09/2017 29/09/2021 Alana Smith
 
Description The goal of this research project is to prepare an appropriately-modified oxide support like silica, tether a cobalt precursor to its surface, and then reduce this cobalt species into well-defined nanoparticles. The aim is to produce sub-nanosized particles with the absence of capping agents and surfactants. So far, throughout the project, we have shown that this might be a viable pathway to sub-sized nanoparticles, though there are several difficulties during the process linked with the high instability of the precursor materials.

· Extensive characterisation/analysis of various silicas has been undertaken, by linking calcination temperature to the density of surface species present across different silicas - techniques include SS-NMR with an external standard, titration of surface species with a Grignard reagent, BET. The hydroxyl-density on the surface of silica can be targeted with a degree of accuracy by changing the calcination temperature. This limits the need for characterisation after calcination, as it can be assumed that the hydroxyl density is the same as what was targeted.

· Have shown that only highly reactive (unstable) cobalt precursors can react with the surface of silica. For example, cobaltocene will not generate the results we are looking for, while cobalt-amide will. These exploratory studies have narrowed our target range of cobalt species so we can focus more on useful precursors that can successfully react with the silica surface in a controlled fashion.

· Have shown that reduction of cobalt precursors on the surface is possible and forms what is believed to be the target nanoparticles - further analysis/characterisation is still ongoing for this step. Precursors have been shown to reduce by the consumption of hydrogen during heating. We have probed the temperature range in which this happens with TPR, and can identify at what temperature reduction will occur
Exploitation Route It will probably be used by Johnson Matthey since they are collaborators
Sectors Chemicals