The CO hydrogenation is a heterogeneously catalyzed reaction and is usually carried out on supported transition metals, in particular Co, Fe and Ru, supported on various solid oxides, such as SiO2, TiO2, Al2O3 or CeO2 among others. Catalytic fixed-bed reactors, such as those used for FT synthesis, are usually operated in stationary mode. However, the dynamic operation might be beneficial for several applications. For example, it was demonstrated that switching from a syngas feed to a H2-rich feed increases production and selectivity towards the liquid fuel fraction (C5 -C20) by draining the liquid filled pores and decreasing mass transport limitations as well as the hydrogenolysis of wax (C20+) filling the pores. Furthermore, due to the volatile nature of renewable energies, a robust and efficient operation of FT reactors under fluctuating feed gas compositions is necessary. For the design of suitable reactors and catalysts, the reaction kinetics have to be known. However, we have already shown that conventional kinetics, derived under steady-state conditions, may fail to describe the CO hydrogenation under transient conditions. Hence, transient kinetic models have to be developed, which consider processes such as ad-/desorption steps or surface reactions. Micro-kinetic models, which take precisely these aspects into account, have already been used for the simulation of dynamic CO and CO2 hydrogenation. However, these models require profound knowledge of the underlying reaction mechanism and sufficient experimental data for model parameterization. For this purpose, sophisticated transient experimental methods are necessary, which carry respective information on the dynamics of the involved reactions. Besides, transient methods have the advantage of being able to cover a wide range of operating conditions in a few experiments. For example, steady-state isotopic transient kinetic analysis (SSITKA) is able to derive kinetic data by switching one reactant with its isotope. The transient response of the isotopically labeled species enables the determination of the amount of the active reaction intermediate, a mean surface residence time and can also demonstrate reversibility of surface reactions and was already applied to investigate the kinetics of the CO hydrogenation. For instance, Vasiliades et al. used SSITKA in combination with operando diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) measurements to investigate the nature of carbonaceous surface intermediates (Cα, Cβ and Cγ) during CO hydrogenation on Co/Al2O3 catalysts. However, in SSITKA only the isotopic composition changes are measured, while the system remains in steady-state. Hence, for the investigation of catalyst dynamics, SSITKA has to be combined with other transient methods. Consequently, Chen et al. used a combination of SSITKA and the chemical transient kinetics (CTK) method to investigate rate limiting steps in CO methanation and revealed that direct CO dissociation is more likely than H-assisted CO dissociation and that O hydrogenation is slow compared to CO dissociation. The CTK method involves the switching between two feed gas compositions, one containing synthesis gas and one containing hydrogen. In addition to the synthesis gas, a noble gas standard is fed into the reactor, which provides information about the residence time distribution (RTD), enabling the separation between residence time and kinetic effects. The CTK method allows the investigation of reversible surface reactions as well as the balancing of the catalyst surface and the calculation of surface coverages for the individual elements. We developed the periodic transient kinetics (PTK) method as an extension of CTK, by switching the feed gas composition periodically. After several switches, the system reaches a limit cycle, in which the individual periods only differ from another by noise. Averaging several periods within the limit cycle and applying statistical analysis provides a step response with a narrow confidence interval and high statistical significance. The goal of the present investigation is to provide the experimental basis for advancing a transient kinetic model for FT synthesis on Co catalysts. We use the PTK method to gather transient experimental data for the CO hydrogenation under FTlike conditions on a Co/TiO2 model catalyst. We also quantify the carbon species Cα and Cβ which are reversibly adsorbed on the catalyst surface. FT-like conditions are chosen, in order to ensure a certain degree of chain growth, which allows to investigate the influence of the different carbon species on the FT mechanism. At the same time, the formation of liquid hydrocarbons is suppressed to prevent mass transport limitations. Our results lay the foundation for subsequent mechanistic analysis of the transient processes and development of appropriate micro-kinetic models.