Eco-friendly upconversion of limestone into value-added calcium formate

Although CaCO(3)is a naturally available, inexpensive, abundant and extensively used chemical in various industries, to date, most of its conversions liberate CO(2)into the atmosphere, which accounts for about 5-6% of global anthropogenic CO(2)emission. Herein, the first synthesis of calcium formate (CF) by hydrogenation of an aqueous mixture of CaCO(3)and CO(2)using a heterogeneous catalyst in an unconventional CO(2)reducing manner is reported. The phosphine-based heterogenized Ru catalyst efficiently converts CaCO(3)into CF with good selectivity (>99%) and is readily separated from the reaction product, resulting in promising recycling ability. Thus, this work provides a promising strategy for the design of green and sustainable conversion of carbonate minerals in industry.