Hydrogenation of carbon dioxide to methanol using a homogeneous ruthenium–Triphos catalyst: from mechanistic investigations to multiphase catalysis

Abstract

The hydrogenation of CO2 to methanol using a recyclable molecular organometallic catalyst in the absence of an alcohol additive is demonstrated for the first time.

CO2‐to‐Methanol Hydrogenation on Zirconia‐Supported Copper Nanoparticles: Reaction Intermediates and the Role of the Metal–Support Interface

“…The proposed mechanism is reminiscent to this recently proposed for Rumolecular catalyst, bridging the gap between molecular catalysis and heterogeneous catalysis. [13] The obtained results clearly point out to the crucial molecular role of the interface between the copper particles and zirconia, [4b, 4e] paving the road toward a more rational design of efficient heterogeneous CO2 hydrogenation catalysts. …”

“…After cooling down to room temperature, the gas phase was evacuated and the solid was analyzed by solid-state NMR. The 1 H- 13 C heteronuclear correlation (HETCOR) spectrum of the sample after reaction at 1 bar is shown in Figure 2a. The correlation of the 13 C HETCOR spectrum of Cu/ZrO2 after two step hydrogenation of 13 CO2 : (1) hydrogenation at 1bar, 230 °C, 12h (2) deuteration at 5 bars, 230 °C, 12h .…”

“…The 1 H- 13 C heteronuclear correlation (HETCOR) spectrum of the sample after reaction at 1 bar is shown in Figure 2a. The correlation of the 13 C HETCOR spectrum of Cu/ZrO2 after two step hydrogenation of 13 CO2 : (1) hydrogenation at 1bar, 230 °C, 12h (2) deuteration at 5 bars, 230 °C, 12h . For HETCOR experiments, ramp cross polarization ( 1 H-13 C) was used with contact time of 0.5 ms.…”

“…First, we selectively prepared 13 C labeled formate adsorbed on the surface (H 13 COO*) by reacting Cu/ZrO2 with a H2/ 13 CO2 mixture (3:1) at 1 bar and 230 °C (Figure 2a). In a second step, following cooling down to room temperature and evacuation of the gas phase (10 -4 mbar, 2 h), the sample was treated with 5 bars of D2 at 230 °C for 12 h. MAS-NMR and IR spectra of the resulting solid were recorded (Figure 2c and S5d).…”

“…IR spectroscopy also reveals a high degree of H/D exchange upon contact of the sample with D2 ( Figure S5d). Nonetheless, quantitative 13 C direct excitation NMR spectrum ( Figure S17) showed that a significant proportion of formate (deuterated or not) was converted into methoxy (about 60 %). Furthermore, the 2D spectrum in solution allowed a rough estimation of the number of methanol adsorbed on the surface prior desorption to about 0.04 par nm -2 , which may be considered as an indication of the number of active sites.…”