Formate is a key chemical building block widely used across industries. Converting carbon dioxide (CO₂) into formate via hydrogenation provides a promising approach to transform a greenhouse gas into a high-value chemical. However, while heterogeneous catalysts based on non-precious metals have been explored for this reaction, their practical application has been limited by low intrinsic reactivity.

To address this issue, a research team from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences has developed a novel catalyst that enables efficient CO₂ hydrogenation to formate. Their findings were recently published in Nature Communications.

The researchers confined cobalt (Co) atoms within the MoS₂ lattice to create highly active sulfur vacancy (SV)-confined Co-Mo sites.

They found that the lower coordination number of Co compared to Mo weakens the bonding interaction between the lattice-confined Co-Mo pair and surface sulfur or oxygen species. This facilitates the hydrogenation-driven removal of sulfur or oxygen, generating SVs. These exposed SV-confined Co-Mo sites—characterized by moderate CO₂ adsorption at both edges and basal planes—suppress C-O bond cleavage and favor formate formation, resulting in superior catalytic activity and selectivity.

The Co-MoS₂ catalyst achieved a formate production rate of 17.0 mmol gcat.-1 h-1 with over 99% selectivity at 200 °C—nearly three times that of pristine MoS₂. Moreover, its activity remained stable for more than 80 hours across eight reaction cycles, demonstrating high durability.

"This work offers a promising method for generating abundant oxygen-tolerant SVs by confining Co in the MoS₂ lattice to modulate its electronic structure, thereby improving the catalytic performance of CO₂ hydrogenation to formate," said Prof. DENG Dehui, corresponding author of the study.