Dry reforming of methane to test passivation stability of Ni/ Al2O3 catalysts (https://doi.org/10.1016/j.apcata.2021.117987)
Robert Franz, Frans D. Tichelaar, Evgeny A. Uslamin, Evgeny A. Pidko
Corresponding author: E.A. Pidko 
Contact Information: e.a.pidko@tudelft.nl

The dataset contains the processed data of the publication with the above-mentioned title, published in Applied Catalysis A: General (https://doi.org/10.1016/j.apcata.2021.117987). The experimental details are described in the publication.

Except for the microscope images, one CSV file exists for every figure in either main text or supporting information and in the files it is clearly marked, which data series belongs to which sample. 

Data acquisition and processing (The descriptions are copied from the above-mentioned paper):

Fig1: Temperature-programmed reduction
Temperature programmed reduction (TPR) was carried out in a dedicated setup equipped with thermal conductivity detector (TCD) and mass-spectrometer (MS). For TPR measurements, 100 mg of sample (particle size 212-355 m) were filled into a quartz reactor (I.D. of 6 mm) and the reactor placed into the furnace. Afterwards, a flow of 30 mL min-1 (10 % H2 in Ar) was started. The setup was heated to 950 C with a ramp of 10 C min-1. H2 consumption was monitored with the TCD downstream of the reactor.

Fig2 & FigS2: Metallic surface obtained from N2O titration
Total metal Ni surface was quantified by N2O titration using the TPR setup described above. Per experiment 200 mg of sample (particle size 212355 m) were mixed with 300 mg SiC (particle size 212355 m) and filled in a reactor quartz reactor (I.D. of 6 mm) and the reactor placed into the furnace.
In a first step, the sample was reduced using a flow of 30 mL min-1 at 800 C for 1 h (heating rate of 10 C min-1). Then, the sample was cooled in 27 mL min-1 of pure Ar to 75 C. At this temperature, a mixture of 20 % N2O in Ar was pulsed into the reactor. This was achieved with the help of a switching valve equipped with a 100 L loop upstream of the reactor. The N2O and N2 signals were tracked using mass spectrometry. N2O was pulsed into the system until no more N2O consumption could be detected.
The Ni surface area was calculated according to the method described by Tada et.al. (https://doi.org/10.1021/jp404291k)

S_Ni,cat = (n_N2O*N_A)/(A*m_cat)

S_Ni,Ni = (n_N2O*N_A)/(A*m_Ni)

where A is the number of Ni atoms per unit area (1.54 * 10e19 m-2), n_N2O the molar N2O consumption as measured with mass spectrometry, N_A Avogadros constant and m_X the mass of either the catalyst or the reduced Ni on the catalyst. The latter was determined by integrating the TCD signal during the initial period of Ni reduction.

Fig3: Nickel particle size distribution (from STEM images)
TEM images were obtained using a FEI Tecnai TF20UT/STEM. The instrument was operated in STEM mode and in brightfield mode. Sample preparation before STEM-analysis consisted of a reduction of 30 mg at 800 C in a flow of 10 % H2 in inert followed by passivation at room temperature. Two different procedures were used for the latter:
The milder procedure was carried out in a reactor tube with a reactor tube with an inner diameter of 1.5 cm. The O2 concentration was increased every 20 min to the following levels: 0.2 %, 1%, 3%, 10 % and 20 %. The harsher procedure was carried out in the same setup as the TPR measurements with steps of 3 %, 10 % and 20 %.

Fig4, Fig5, Fig 6, FigS6, Fig S7: Catalytic activity of Ni/Al2O3 catalysts
Samples were tested for their catalytic activity in dry reforming of methane in a single-reactor system. In this system, a quartz reactor (I.D. of 4 mm) is placed in a furnace. Upstream of the reactor, mass flow controllers (Bronkhorst) regulate the flow of N2, CH4, CO2 and H2 to the reactor. Downstream of the reactor a compact GC equipped with a TCD was used for the online product analysis. Product separation was achieved using a micropacked column (ShinCarbon ST 80/100 2 m, 0.53 mm I.D.).
Conversion of methane and CO2 was calculated using N2 as the internal standard according to the following equation: 

X_R = ((A_R/A_N2)_0 - (A_R/A_N2))/(A_R/A_N2)_0

where R is the reactant in question (either CH4 or CO2) and A is the peak area in the GC. In a typical catalytic experiment, 10 mg of sample (355425 m) were diluted in 140 mg of SiC (212300 m). This mixture was filled into the quartz reactor between two plugs of quartz wool and upstream of a 9 cm layer of SiC (212-425 m). Upstream of the catalyst-SiC mixture, 7 cm of SiC (212425 m) provided pre-warming of the feed.
For freshly calcined samples, the sample was heated in a stream of 10 % H2 in N2 (50 mL min-1) to 800 C (10 C min-1) and reduced at this temperature for 1 h, before being cooled to 650 C. At this point, the flow was switched to 100 mL min-1 of 25 % CH4 and 25 % CO2 in N2. Afterwards, dry reforming experiments were carried out for 12 h. If the sample was already pre-reduced and passivated, the sample was directly heated to 650 C in 10 % H2 in N2 (50 mL min-1). Once the reaction temperature was reached, the dry reforming experiment started. 
The catalytic activity of the freshly calcined sample was measured for two different batches of the same loading. The difference in catalytic activity was used to determine the experimental error.

Fig7 & Fig8: Coke contents after reaction in wt.%
After each catalytic experiment, the coke content of the sample was analyzed via TGA (Mettler-Toledo TGA/SDTA 851e).

