Advanced catalytic CO₂ hydrogenation on Ni/ZrO₂ with light induced oxygen vacancy formation in photothermal conditions at medium-low temperatures

Abstract

Selective CH4 formation from CO2 hydrogenation is an appealing yet challenging sunlight-driven or thermal-driven process due to low solar energy utilization efficiency or high energy input.

Recent advances in CO2 reduction with renewable reductants under hydrothermal conditions: towards efficient and net carbon benefit CO2 conversion

“…Li et al 96 chose L-alanine as the model chemical to verify the feasibility of hydrothermal CO 2 reduction by amino acid. In the presence of NaHCO 3 , there was a significant increase in formate yield (9.3%), a finding also corroborated by 13 C-NMR analysis with NaH 13 CO 3 as the reactant. A screening of active metal catalysts (Cu, Co, Ni, Ru, Pd, and Pt) and suitable supports (SiO 2 , CeO 2 , ZrO 2 , ZnO, and gamma-Al 2 O 3 ) for hydrothermal NaHCO 3 reduction with Lalanine was conducted, where Pd/γ-Al 2 O 3 exhibited higher activity, achieving a formate yield of 49.0% under conditions of 0.8 mol/L L-alanine and 0.8 mol/L NaHCO 3 at 325 °C for 2 hours, with 0.08 g of 5% Pd/γ-Al 2 O 3 .…”

“…A formate yield of 68% was achieved in the hydrothermal NaHCO 3 reduction with methanol at 180 °C using a Pd 0.5 Cu 0.5 /C catalyst. 13 C-qNMR analysis was conducted to distinguish and quantify formate production from NaHCO 3 and CH 3 OH. Approximately 55% of the formate originated from HCO 3reduction, while the remaining 45% resulted from CH 3 OH oxidation.…”

“…Furthermore, the synergistic transformation of PVC plastics and CO 2 was achieved even without the use of any external metal-based catalysts. 13 C-NMR analysis was performed on the liquid sample derived from the reaction of NaH 13 CO 3 and PVC. As depicted in Figure 14a, the labeling experiment using NaH 13 CO 3 revealed a strong signal attributed to H 13 COO − at a chemical shift of 171.1 ppm in the 13 C-NMR spectrum, confirming formate originated from NaHCO 3 105 .…”

“…13 C-NMR analysis was performed on the liquid sample derived from the reaction of NaH 13 CO 3 and PVC. As depicted in Figure 14a, the labeling experiment using NaH 13 CO 3 revealed a strong signal attributed to H 13 COO − at a chemical shift of 171.1 ppm in the 13 C-NMR spectrum, confirming formate originated from NaHCO 3 105 . Research on reaction characteristics indicated that higher temperatures (over 300 °C) and longer times (more than 8 hours) can lead to formate decomposition, and higher NaHCO 3 concentrations (more than 4 mmol) can cause an insufficient amount of PVC as the reductant.…”

“…This consideration aligns with the growing consensus that sustainability should be integrated into the performance metrics of conversion systems 6 . In recent years, various catalytic methods have been applied to convert CO 2 into high-value-added products including catalytic hydrogenation 7,8 , photo-catalysis 9,10 , electrocatalysis 11,12 , and the recent risen photo-thermal catalysis 13,14 , photoelectro catalysis 15,16 . During these processes, carbon-containing compounds like formic acid, methanol, methane, acetic acid, ethylene, and even long-chain alkanes are formed, which can serve as chemical stocks or fuels up to the circumstances [17][18][19] .…”