A neutron imaging study of ethyne hydrogenation over supported palladium catalysts

In May 2023 the applicants used the IMAT facility to obtain vivid images of hydrogen adsorption and desorption over carbon-supported Pd catalysts (RB2220700). Follow-on measurements in July 2023 expanded the concept further by examining the hydrogenation of ethyne over a 5 wt% Pd/C powder catalyst in a stainless-steel reactor (RB2310426). Although problems were experienced with in-line analytical facilities, the neutron imaging measurements were successful and revealed differences in how hydrogen partitioned throughout the catalyst bed during continuous ethyne turnover. Further imaging measurements are scheduled in May 2024 that will develop new Sample Environment capability, which will enable operando experiments to be undertaken (RB2410647).

This proposal requests a new allocation of IMAT beamtime to further extend the ethyne hydrogenation investigations to image hydrogenation activity in regimes of low and high hydrogen supply. Crucially, the latter configuration will broach the concept of catalyst deactivation, which will provide data suitable for kinetic analysis.

The application of neutron imaging techniques to inspect hydrogenation reactions at the gas/solid interface is novel and requires careful and informed development to establish the technique’s full potential. Endorsement of the applicability of the approach adopted is evidenced by Johnson Matthey’s provision of an EPSRC Industrial CASE award for this endeavour.