Boosting the Simultaneous Conversion of Glycerol and CO <sub>2</sub> to Lactate and Formate Using ZrO <sub>2</sub> ‐Supported NiO Catalyst
Sudip Bhattacharjee, Unnikrishnan Pulikkeel, Vipin Amoli, Mukaddar Sk, Ranjit Thapa, Biswajit Chowdhury, Thomas E. Müller, Praveen Kumar Chinthala, Asim Bhaumik
Abstract
Abstract Glycerol, a by‐product of biodiesel production, and CO 2 , a major greenhouse gas, are abundant but underutilized feedstocks. Their simultaneous conversion into formic acid and lactic acid presents an innovative and sustainable approach to addressing environmental challenges. Formic acid, a versatile compound in multiple industries, and lactic acid, a versatile platform chemical used in food, pharmaceuticals, and biodegradable plastics, hold immense commercial value. In this work, a NiO─ZrO 2 catalyst synthesized through incipient wetness impregnation is employed to achieve the simultaneous conversion of CO 2 and glycerol in an alkaline medium. Comprehensive characterisation of the catalyst using PXRD, Raman spectroscopy, XPS, BET surface area, CO 2 /NH 3 ‐TPD, H 2 ‐TPR, and UHR‐TEM analysis revealed its unique properties, including weak Lewis acid sites critical to its performance. Under optimal reaction conditions, 200 °C, 40 bar CO 2 , and KOH as the base, the catalyst achieved yields of 3.26 mmol of formate and 11.20 mmol of lactate. The synergistic interaction between NiO and ZrO 2 , along with the in situ formation of carbonate salts, is key to the high efficiency. An initial economic assessment demonstrates the commercial viability of co‐producing formic and lactic acid, with the glycerol price and the efficiency of converting the formate and lactate salts to the corresponding acids being critical factors for the economic feasibility of the process.