Carbon-based materials for electrochemical dechlorination

Electrochemical dechlorination reaction(EDR)is a promising,environmentally friendly,and economically profitable technology for treating chlorinated organic pollutants.For efficient environmental protection,electrocatalysts with high stability and low cost are of extremely significance to the development of EDR technology.Carbon-based materials have aroused broad interest as electrocatalysts for many electrochemical reactions due to their characteristics including large specific surface area,controllable structure,good conductivity,and chemical stability.For EDR,the carbon-based materials also show many unique superiorities,like strong adsorption capacity to chlorinated organic compounds(COCs),excellent catalytic activity and stability,and environmental compatibility.This review starts with a detailed summary on the mechanisms of electrochemical dechlorination(direct and indirect electron transfer pathway)and factors affecting the effectiveness of EDR.Then the paper comprehensively overviews the current progresses of carbon-based materials for EDR of COCs,following their two major application scenarios,i.e.,directly as electrocatalysts and as advanced supports for other catalysts.Moreover,the formation of different active sites in carbon-based electrocatalysts and their EDR activities are analyzed.Finally,the current challenges and perspectives in this field are discussed.This review will provide an in-depth understanding for the design of advanced carbon-based materials and promote the development of EDR technology.

Enhanced catalytic complete oxidation of 1,2-dichloroethane over mesoporous transition metal-doped γ-Al_2O_3

High-surface-area mesoprous powders of γ-Al2O3 doped with Cu^2＋, Cr^3＋, and V^3＋ ions were prepared uia a modified sol-gel method and were investigated as catalysts for the oxidation of chlorinated organic compounds. The composites retained high surface areas and pore volumes comparable with those of undoped γ-Al2O3 and the presence of the transition metal ions enhanced their surface acidic properties. The catalytic activity of the prepared catalysts in the oxidation of 1,2-dichloroethane （DCE） was studied in the temperature range of 250-400℃. The catalytic activity and product selectivity were strongly dependent on the presence and the type of dopant ion. While Cu^2＋- and Cr^3＋-containing catalysts showed 100% conversion at 300℃ and 350℃, V3＋-containing catalyst showed considerably lower conversion. Furthermore, while the major products of the reactions over γ-alumina were vinyl chloride （C2H3Cl） and hydrogen chloride （HCl） at all temperatures, Cu- and Cr-doped catalysts showed siguiticantly stronger capability for deep oxidation to CO2.