The Influence of Transitional Metal Dopants on Reducing Chlorine Evolution during the Electrolysis of Raw Seawater

Electrocatalytic water splitting is a possible route to the expanded generation of green hydrogen; however, a long-term challenge is the requirement of fresh water as an electrolyzer feed. The use of seawater as a direct feed for electrolytic hydrogen production would alleviate fresh water needs and potentially open an avenue for locally generated hydrogen from marine hydrokinetic or off-shore power sources. One environmental limitation to seawater electrolysis is the generation of chlorine as a competitive anodic reaction. This work evaluates transition metal (W, Co, Fe, Sn, and Ru) doping of Mn-Mo-based catalysts as a strategy to suppress chlorine evolution while sustaining catalytic efficiency. Electrochemical evaluations in neutral chloride solution and raw seawater showed the promise of a novel Mn-Mo-Ru electrode system for oxygen evolution efficiency and enhanced catalytic activity. Subsequent stability testing in a flowing raw seawater flume highlighted the need for improved catalyst stability for long-term applications of Mn-Mo-Ru catalysts. This work highlights that elements known to be selective toward chlorine evolution in simple oxide form (e.g., RuO2) may display different trends in selectivity when used as isolated dopants, where Ru suppressed chlorine evolution in Mn-based catalysts.

Preparation of Polyaniline Nanofibers And Experimental Study On Their Electrochemical Properties And Conductivity

Among nano polyaniline materials, polyaniline nanofibers are the most important. The low conductivity and poor processability have become the biggest obstacles to the application of polyaniline as a practical material. The excellent characteristics of new polyaniline nanofiber materials can just overcome the shortcomings of Polyaniline in forming and processing. In this study, a new polyaniline nanofiber was prepared by chemical oxidation, its structure was characterized, the mechanism of improving its conductivity was studied, and its superior electrocatalytic activity was evaluated by Electrochemical performance test. The results show that the diameter of polyaniline nanofibers is 20nm ~ 50nm and the fiber length is 2µm ~ 5µm. The structure is uniform and the conductivity can reach 13.5 S/cm. he electrocatalytic activity of polyaniline nanofibers for oxygen evolution and chlorine evolution was systematically tested. It was found that the electrocatalytic activity of polyaniline nanofibers for oxygen evolution was higher than that of polyaniline nanofibers. The electrocatalytic activity of carbon paper electrode prepared by β-PbO2 nano powder is superior to that of traditional chlorine evolution anode Ti/RuO2.

Application of Pd-Sn Modified Ru-Ir Electrode For Treating High Chlorine Ammonia-Nitrogen Wastewater

Electro-catalytic technology has attracted increasing attention as a promising approach for wastewater treatment, owing to its easy operation, minimal generation of secondary pollution, small foot-print and rapid start-up. In this work, the chlorine evolution potential of the Pd-Sn modified ruthenium(Ru)-iridium(Ir) electrode was investigated for electro-catalytic treatment of high chlorine ammonia-nitrogen wastewater. The effect of reaction conditions on the removal of ammonia-nitrogen, kinetics and apparent activation energy of the electro-catalytic treatment of ammonia-nitrogen were studied. The possible denitrification process of high chlorine ammonia-nitrogen wastewater treated by electrocatalysis was discussed. The results indicated that the chlorine evolution potential of the Pd-Sn modified Ru-Ir electrode was 1.0956 V(vs. SCE). The rule of electro-catalytic treatment of high chlorine ammonia-nitrogen conformed to zero-order kinetics, and the removal process was endothermic reaction with the apparent activation energy of 14.089 kJ/mol. With the current is 0.5 A, the removal efficiency of ammonia-nitrogen could achieve 100% at the reaction time of 40 min. Indirect oxidation played an essential role in the electro-catalytic ammonia-nitrogen removal using the Pd-Sn modified Ru-Ir electrode. This paper demonstrated that the electro-catalytic technology was a promising approach for efficiently treating the high chlorine ammonia-nitrogen wastewater.

Efficient hydrogen production by saline water electrolysis at high current densities without the interfering chlorine evolution

Seawater electrolysis powered by renewable energy sources has been proposed to be a potentially cost-effective approach to green hydrogen production. However, the long-standing issue regarding the chlorine evolution reaction (CER)...