Table 2.
Catalytic performance of the gold nanocatalysts for CO2 hydrogenation
| Entry | Solvent | P(H2)/P(CO2) MPa | Base | Time/h | HCOOH/M | TONa |
|---|---|---|---|---|---|---|
| 1b | H2O/CH3OH | 5.0/3.0 | NEt3 | 12 | – | – |
| 2 | H2O/CH3OH | 5.0/3.0 | NEt3 | 12 | 0.518 | 14,470 |
| 3c | H2O/CH3OH | 5.0/3.0 | NEt3 | 12 | 0.08 | 1026 |
| 4d | H2O | 5.0/3.0 | NEt3 | 12 | 0.689 | 9624 |
| 5d | Methanol | 5.0/3.0 | NEt3 | 12 | 0.702 | 9806 |
| 6d | Ethanol | 5.0/3.0 | NEt3 | 12 | 0.297 | 4148 |
| 7d | n-Hexane | 5.0/3.0 | NEt3 | 12 | 0.025 | 349 |
| 8d | Cyclohexane | 5.0/3.0 | NEt3 | 12 | 0.013 | 181 |
| 9 | H2O/CH3OH | 5.0/0 | KHCO3 | 5 | 0.009 | 251 |
| 10 | H2O/CH3OH | 5.0/3.0 | KHCO3 | 5 | 0.107 | 2989 |
| 11 | H2O/CH3OH | 5.0/0 | NaHCO3 | 5 | 0.007 | 195 |
| 12 | H2O/CH3OH | 5.0/3.0 | NaHCO3 | 5 | 0.063 | 1760 |
| 13e | H2O/CH3OH | 5.0/3.0 | NEt3 | 12 | – | – |
| 14f | H2O/CH3OH | 5.0/3.0 | NEt3 | 12 | 0.021 | 1207 |
Reaction conditions: 5 mg Au/SiO2-Schiff catalyst, 90 °C, 10 mL reagent, 15 mmol base, 600 rpm, H2O/CH3OH (20:80 vol/vol)
aThe TON is calculated by the Supplementary Equation 1. The number of replicates for each experiment was n ≥ 2
bCatalyst was 5 mg Au/SiO2
cCatalyst was 5 mg Au/SiO2-NH2
dCatalyst was 10 mg Au/SiO2-Schiff
eThe single-atom catalyst was prepared by solid-state reduction method
fThe 3.2-nm nanocatalyst was prepared by surface functional group-promoted in situ reduction method