Room-temperature CO2 conversion to carbon using liquid metal alloy catalysts without external energy input

Abstract

Conversion of CO₂ to carbon using a catalyst typically requires significant energy input such as heat, pressure, or electricity. This is due to its strong bonds and the energy needed to initiate the reaction. The energy requirement for CO₂ conversion may also lead to carbon emissions if sources are fossil-based. There is less exploration at low temperatures and without an external energy CO₂ conversion to solid carbon. Here, we show a liquid metal alloy (In_0.2Ga_0.8) used as a catalyst for converting CO₂ to carbon at room temperature without external energy. The carbon formed was characterized, and the calculated free energy of the reduction reaction was −530 kJ mol⁻¹.The catalyst coated over a ceramic surface observed similar phenomena of CO₂ conversion to carbon at room temperature. The conversion was five times higher at catalyst-coated ceramic membranes than at bulk catalysts. The CO₂ conversion efficiency was 60 % at the catalytic membrane for continuous flow of CO₂ at room temperature. EDX and XPS studies confirmed the formation of carbon at the catalyst surface. Our study may open the topic of membrane-based catalysis of CO₂ for practical carbon conversion at lower operating costs at the industrial scale to achieve net-zero emissions.