Efficient CO₂/(bi)carbonate hydrogenation to formate is achieved over Ni₉Pd₁ catalyst with low Pd content, even at ambient conditions, with appreciable stability over several catalytic cycles, attributed to the NiPd synergistic interactions. Further, integrating the direct air capture (DAC) with CO₂/(bi)carbonate hydrogenation makes it a more sustainable CCU process.

Abstract

The urgent need for sustainable CO₂ management has driven the development of efficient catalytic systems capable of converting CO₂ into value-added chemicals under mild conditions. Herein, we report a Ni₉Pd₁ catalyst with a low Pd content (Ni/Pd = 9:1) for the selective CO₂ hydrogenation to formate at low temperatures. Remarkably, this catalyst exhibits exceptional versatility, efficiently hydrogenating both aqueous (bi)carbonate and CO₂ captured from air (as carbonate) to formate. Moreover, this catalyst shows appreciable robustness by achieving cumulative formate yields of 770.5 mmol g_Pd ⁻¹ (TON of 82, STY of 32.18 mmol_formate g_Pd ⁻¹ h⁻¹ at 28 °C) and 1371.9 mmol g_Pd ⁻¹ (TON of 146, STY of 57.16 mmol_formate g_Pd ⁻¹ h⁻¹ at 80 °C) over multiple cycles. The synergistic Ni-to-Pd interaction in this catalyst leads to the efficient CO₂ activation and H₂ dissociation, enabling operation under mild conditions. This study demonstrates an integrated and sustainable approach where CO₂ captured from air can be hydrogenated to formate at low temperature.