Hui Ma, Siqi Zhao, Kim Daasbjerg, Rasmus Jakobsen, Shengyan Pu, Hans Christian B. Hansen
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引用次数: 0
Abstract
Electro-dehalogenation for the clean-up of carcinogenic chloroethylenes (CEs) in groundwater is hindered by the high operating costs of metal electrodes and low efficiency due to competing water reduction and hydrogen formation. This study prepared metal-free electrodes with high Faradaic efficiency (FE) up to 50 % in aqueous solution by coating nitrogen-doped graphene nanoplatelets (N-GPs) on carbon paper. Dechlorination rates at these N-GPs electrodes were enhanced by ∼15 times compared with the plain graphene-based electrode, with first-order rate constants of 0.28, 0.33, 0.41, and 0.048 h−1 for tetrachloroethylene (PCE, 22 μM), trichloroethylene (TCE, 22 μM), cis-dichloroethylene (cis-DCE, 22 μM), and vinyl chloride (VC, 11 μM) dechlorination to acetylene and ethene (VC), respectively, at −1.0 V vs standard hydrogen electrode (SHE), and initial neutral pH. Surprisingly, extremely low N or no-N containing GP was detected from highly reactive N-GPs. Despite the N-doping process has been wildly used for improving electrocatalytic reactivity of catalysts by inducing N-functional groups, this study suggests that, the polygonal intrinsic defects formed after N burn-off may act as dechlorination active sites. The N-GP electrodes showed appreciable stable performance over 24 h (five cycles). Simultaneous electrolysis of a mixture of CEs in groundwater without the addition of supporting electrolytes achieved >90 % reduction of PCE, TCE, and cis-DCE and ∼60 % reduction of VC within 24 h at −1.23 V vs SHE, demonstrating its superior performance and great potential of these electrodes in practical applications.
期刊介绍:
The Chemical Engineering Journal is an international research journal that invites contributions of original and novel fundamental research. It aims to provide an international platform for presenting original fundamental research, interpretative reviews, and discussions on new developments in chemical engineering. The journal welcomes papers that describe novel theory and its practical application, as well as those that demonstrate the transfer of techniques from other disciplines. It also welcomes reports on carefully conducted experimental work that is soundly interpreted. The main focus of the journal is on original and rigorous research results that have broad significance. The Catalysis section within the Chemical Engineering Journal focuses specifically on Experimental and Theoretical studies in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. These studies have industrial impact on various sectors such as chemicals, energy, materials, foods, healthcare, and environmental protection.