Nonthermal plasma (NTP) activated metal–organic frameworks (MOFs) catalyst for catalytic CO₂ hydrogenation

A systematic study of Ni supported on metal–organic frameworks (MOFs) catalyst (i.e., 15Ni/UiO-66) for catalytic CO₂ hydrogenation under nonthermal plasma (NTP) conditions was presented. The catalyst outperformed other catalysts based on conventional supports such as ZrO₂, representing highest CO₂ conversion and CH₄ selectivity at about 85 and 99%, respectively. We found that the turnover frequency of the NTP catalysis system (1.8 ± 0.02 s⁻¹) has a nearly two-fold improvement compared with the thermal catalysis (1.0 ± 0.06 s⁻¹). After 20 hr test, XPS and HRTEM characterizations confirmed the stability of the 15Ni/UiO-66 catalyst in the NTP-activated catalysis. The activation barrier for the NTP-activated catalysis was calculated as ~32 kJ mol⁻¹, being lower than the activation energy of the thermal catalysis (~70 kJ mol⁻¹). In situ DRIFTS characterization confirmed the formation of multiple carbonates and formates on catalyst surface activated by NTP, surpassing the control catalysts (e.g., 15Ni/α-Al₂O₃ and 15Ni/ZrO₂).