Hydrogenation of CO2 Promoted by Silicon-Activated H2S: Origin and Implications

Unlike the usual method of COx (x = 1, 2) hydrogenation using H-2 directly, H2S and HSiSH (silicon-activated H2S) were selected as alternative hydrogen sources in this study for the COx hydrogenation reactions. Our results suggest that it is kinetically infeasible for hydrogen in the form of H2S to transfer to COx at low temperatures. However, when HSiSH is employed instead, the title reaction can be achieved. For this approach, the activation of CO2 is initiated by its interaction with the HSiSH molecule, a reactive species with both a hydridic H delta- and protonic H delta+. These active hydrogens are responsible for the successive C-end and O-end activations of CO2 and hence the final product (HCOOH). This finding represents a good example of an indirect hydrogen source used in CO2 hydrogenation through reactivity tuned by silicon incorporation, and thus the underlying mechanism will be valuable for the design of similar reactions.

Automated summary

This study explored the use of H2S and HSiSH as alternative hydrogen sources for COx hydrogenation reactions. While H2S was found to be kinetically infeasible for transferring hydrogen to COx at low temperatures, HSiSH successfully activated CO2 to produce the final product HCOOH through C-end and O-end activations of CO2. This finding demonstrates the potential of utilizing indirect hydrogen sources with silicon incorporation for CO2 hydrogenation reactions.