Hydrogen along with carbon dioxide into value-added chemicals: Sodium borohydride mediated formic acid production-via highly active and selective NiO-CuO@ZrO2 catalyst

Hydrogen (H2) serves as a key feedstock and, along with carbon dioxide (CO2), offers a promising pathway to enable the production of value-added compounds while contributing to greenhouse gas mitigation and Power-to-X technology strategies. This study focuses on the synthesis of highly active and selective zirconium dioxide-supported nickel(II) oxide and copper(II) oxide (NiO-CuO@ZrO2) catalysts for the efficient conversion of CO2 into value-added chemicals, such as formic acid (HCOOH), mediated by sodium borohydride (NaBH4). The catalytic activity is systematically evaluated using a central composite design (CCD) by varying key operational parameters, including temperature, pressure, and NiO-CuO@ZrO2-to-NaBH4 wt% ratio. Based on CCD results, the optimal process conditions-51 degrees C temperature (x1 = 1.1), 1.2 bar pressure (x2 = -1.9), and 10.8 wt% NiO-CuO@ZrO2/NaBH4 ratio (x3 = -0.84)-yielded a conversion efficiency (CE, %) value of 99.4 wt% with desirability (D) value of 1. Furthermore, the experimental results confirm HCOOH selectivity of 99.99 %, highlighting the effectiveness of NaBH4 in the selective synthesis of HCOOH catalyzed by NiO-CuO@ZrO2 catalyst.