A study of a series of Mn-doped, TiO2-supported Co Fischer-Tropsch catalysts have shown surprising selectivity towards alcohols. Previous XRD-CT experiments conducted provided some insight into the progression of the cobalt phases during reduction and reaction at various doping levels, however the Mn phases were not observable due to their high dispersion. Observing these catalysts under operando conditions (Fischer-Tropsch reaction at 20 bar gas (barg)) via combined μ-XRD-CT/μ-PDF-CT with a spatial resolution ~ 1 μm will provide valuable understanding into the Mn (and Co) species present during catalysis, and so provide insight into the cause of the observed selectivity changes.