High-efficiency carbon dioxide reduction using catalytic nonthermal plasma desorption

To sustainably reduce carbon dioxide (CO2) emissions at ambient temperature and atmospheric pressure, CO2 is reduced to carbon monoxide (CO) using nonthermal plasma (NTP) flow and a catalyst. In a liquefied natural gas (LNG) gas-turbine combined power generation plant with high power generation efficiency, CO2 zero-emission can be achieved for the power plant if the energy efficiency of CO2 reduction by NTP is at least 49%. In this study, CO2 reduction performance is evaluated for a two-step process using different gas mixtures. First, CO2 is adsorbed from a gas flow mixture of nitrogen (N2) and CO2 (~10% concentration) by an adsorbent; second, CO2 is desorbed and concentrated by NTP flow to a higher concentration from 19% to 25% and reduced by N2 NTP flow and a catalyst under all experimental conditions. γ-alumina, copper, and copper doped alumina are used as catalysts, and the results are compared with those of a previous study where zeolite was used. The energy efficiency increases with the elapsed time and can reach 9−11%. When using copper doped alumina, plasma-catalysis promotes CO2 reduction even in low-temperature environments at ~80 ℃, resulting in a higher CO concentration relative to the CO2 concentration and the highest efficiency of all tested catalysts: conversion efficiency is 18% and energy efficiency is 11%.