Data from a paper on hydrogen vacancy-driven C-H photothermal activation on Ni/TiH₂ catalysts

UV-vis-NIR diffuse reflectance spectra (DRS) were recorded using a Shimadzu UV-3600 spectrometer over a wavelength range of 200–800 nm with BaSO4 as a reference. Reaction conditions for Arrhenius plot measurements matched those used in the flow reaction system performance evaluation. And the transient photocurrent response (I-t) as well as the electrochemical impedance spectra were subsequently measured using an electrochemical workstation equipped with a standard three-electrode system (CHI-760E, Chenhua).

A mixture of 5 mg of catalyst, 20 μL of Nafion, and 500 μL of DMF was prepared, followed by ultrasonication for 30 minutes. The resulting solution was then deposited onto conductive glass. After allowing the conductive glass to air dry naturally, it was immersed in a 0.1 mol/L Na2SO4 solution, and the electrode was attached to initiate the test.

In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) for temperature-programmed surface reaction (TPSR) was conducted using a Thermo Scientific Nicolet iS50 FT-IR with a liquid nitrogen-cooled MCT detector, Infrared spectra within the 4000–1000 cm−1 range for the catalyst were collected by accumulating 32 scans with the step size of 8 cm−1. The catalyst was loaded into a Harrick reaction chamber holder.

Prior to measurement, pre-reduced samples were purged with pure Ar at 200 °C for 30 minutes. The temperature was lowered to room temperature (RT) for background data collection. A 5% CO2/Ar stream (30 mL/min) was introduced at RT, and spectral data were recorded until peak signals stabilized.

The temperature was sequentially increased to 100, 200, 300, and 400 °C, with data recording initiated after stabilization. Pure Ar was introduced for 20 minutes to remove physically adsorbed CO2 after recording. After cooling to RT, a 5% CH4/Ar stream was introduced, and the procedure was repeated.

For light experiments, the initial temperature was the stable temperature of the catalyst after being exposed to Xe lamp light source. Spectra were recorded over the range of 4000–600 cm-1 with a resolution of 8 cm-1. Isotope tracking experiments were carried using the Hiden HPR-20 mass spectrometer.

Load 50 mg of catalyst into a quartz tube and introduce reaction gas (flow rate=10 mL min-1, CD4 : CO2 : Ar = 4:4:2), then heat up from 200 °C to 500 °C with light illumination (2 W cm-2). Record the MS signal of CO (m/z=28), H2 (m/z=2), HD (m/z=3), D2 (m/z=4), CO2 (m/z=44) and CD4 (m/z=20). In situ synchrotron radiation XPS were recorded at BL10B in National Synchrotron Radiation Laboratory.

After purging the sample with Ar for 30 minutes, vacuuming was performed to start the test. After the test was completed, 5%CO2/Ar was introduced, and the temperature was raised to 300 °C for a reaction of 30 minutes. Then, the temperature was lowered and vacuuming was performed to start the test.