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The greenhouse gas carbon dioxide (CO2) was converted to a novel CO2 conversion material (electrolytic carbon, EC) by molten salt electrochemical conversion, which served as the carbon source to prepare an iron–carbon composite (Fe–EC). The composite was used to activate persulfate (PS) and degrade 2,4-dichlorophenol (2,4-DCP) in an aqueous solution. The effects of several essential operating parameters such as PS dosage and pH on 2,4-DCP degradation were investigated. The removal efficiency of 2,4-DCP (20 mg L–1) was 97.8% in the presence of Fe–EC (50 mg L–1) and PS (1 mmol L–1). Moreover, the average % reaction stoichiometric efficiency (RSE) (calculated for all selected times 5–60 min) was maintained at 23.07%. Electron paramagnetic resonance (EPR), classical radical scavenging experiments, and density functional theory (DFT) calculations were integrated for a mechanistic study, which disclosed that the active species in the system were identified as SO4⦁–, •OH, and O 2 ⦁ − . Moreover, the iron–carbon micro-electrolysis/PS (ICE-PS) system had a high tolerance to a wide range of pH, which would provide theoretical guidance for the treatment of organic pollutants in practical industrial wastewater.

The electrolytic carbon (E-carbon) derived from greenhouse gas CO 2 in molten carbonates at mild temperature possesses high electrical conductivity and suitable specific surface area. In this work, its potential as catalyst is investigated towards oxygen reduction reaction (ORR). It is revealed that the pristine E-carbon has no electrocatalytic activity for the ORR due to its high surface content of carboxyl group. The carbon was then treated in a Li 2 SO 4 containing Li 2 CO 3 -Na 2 CO 3 -K 2 CO 3 molten salt at 550 °C. Sulfur modified E-carbon was obtained in the melt via a galvanic sulfidation reaction, in which Li 2 SO 4 served as a nontoxic sulfur source and an oxidant. The sulfur modified E-carbon showed a significantly improved electrocatalytic activity. Subsequently, a sulfur/cobalt dual modified carbon with much higher catalysis activity was successfully prepared by treating an E-carbon/CoSO 4 composite in the same melt. The dual modified E-carbon showed excellent catalytic performance with activity close to the commercial Pt/C catalyst but a high tolerance towards methanol.

We identify a method and its mechanism for producing nanostructured graphite via the electrochemical reduction of synthetic flue gas (a mixture of CO2 and SO2) in molten Li2CO3–Na2CO3–K2CO3–Li2SO4 at a relatively low temperature (775 °C), the lowest temperature reported for artificial graphite preparation without a metal or metal compound catalyst.