Xe t detector

The film thickness was measured by the SENPro spectroscopic ellipsometer from SENTECH. The measurements were carried out at an angle of 70°, and on a spectral range of 370–1050 nm. The film thickness was fitted with a model consisting of air/HfS₂/SiO₂/Si stacks. The crystal structure of the deposit was characterized by X-ray diffraction (XRD) using a Bruker (Germany) D8 advance diffractometer equipped with a Cu Kα radiation source and a LynxEye XE-T detector. Energy dispersive X-ray spectroscopy (EDX) and the corresponding scanning electron microscopy images were acquired using a JEOL (Japan) JSM 6400 PC system equipped with a LaB₆ cathode and SDD X-ray detector. All other SEM images were acquired using a Zeiss (Germany) Gemini 500. X-ray photoelectron spectroscopy (XPS) spectra were recorded with monochromatized Al K_α radiation (PHI Quantera II, Japan), all the spectra were calibrated with the C 1s binding energy 284.6 eV. A quartz crystal microbalance (QCM, purchased from Novaetech Srl) was used for the determination of the in situ growth of HfS₂.

XRD was acquired with a D8
Advance diffractometer (Bruker AXS) equipped with a Cu Kα source
and a LynxEye XE-T detector. XRD patterns were recorded in a 2θ
range of 20–90°, applying an increment of 0.005°.
Rietveld refinement was performed using the software package TOPAS
(Bruker AXS) to analyze the diffraction pattern.
For in situ XRD the samples were loaded in a reaction cell that
is connected to a gas manifold consisting of multiple mass flow controllers.
This way a consistent and accurate gas flow is achieved. Catalyst
reduction was performed in 10% H₂ in He at atmospheric
pressure with a total flow rate of 100 mL/min and a temperature range
from 100 to 250 °C. Measurements were performed in steps of 10
°C. After the reduction, the reaction gas mixture was introduced
H₂ + CO₂ (3:1) and the cell pressurized to 10
bar. Measurements under reaction conditions were performed at 220,
250, and 400 °C. Diffractograms under reaction conditions were
acquired after staying for 2 h at each condition. Additional remarks
regarding the background during the in situ XRD measurements
are given in Supplementary Note 1 together
with Figure S1.

The XRD patterns were recorded using a Bruker-AXS D8 Advance diffractometer equipped with a Cu K_α source and a position-sensitive energy-dispersive LynxEye XE-T detector. XRD patterns were recorded in continuous scanning mode in a 2θ range of 20–90 °, applying an increment 0.02 ° and a variable divergence slit configuration ensuring constant sample illumination.
Rietveld refinement was performed using the software package TOPAS^® (Bruker-AXS) to analyze the diffraction patterns taking into account instrumental broadening, zero error, and sample displacement. Owing to the structural complexity of the Al₂O₃, no Rietveld refinement was performed on the CuZn/Al₂O₃ diffraction pattern. Furthermore, the diffraction signals of the SiO₂ support were considered as convolution of individual peaks, which made a Rietveld quantification impossible. The results of the XRD experiments are shown in Supplementary Figure 6 and Supplementary Tables 3–6.