Synthesis Of Superaerophobic Nanostructured Electrodes And Their Application In Gas Evolution Reactions

The development of sustainable energy resources is of great importance to solve the increasing global demand for energy and the environmental pollution caused by burning of fossil fuels.Gas evolution reaction?GER?is an important and large branch in the energy conversion system.As the typical GER,oxygen evolution reaction?OER?,hydrogen evolution reaction?HER?and chlorine evolution reaction?ClER?are significant parts of the chemical industry.Water splitting driven by electricity or sunlight is widely considered to be critical for renewable hydrogen production.The key to reduce energy supply and maximize the water splitting efficiency lies in the electro-catalyst screening for OER and HER.However,many electrocatalysts are usually active for a single half reaction because of the instability of the catalysts under the other half reaction conditions.Therefore,developing advanced bifunctional electrocatalysts for water splitting is rarely achieved and still remains a big challenge.Meanwhile,the chlor-alkali electrolysis is one of the most important bulk products in modern electrochemical industry,and the products can be widely used for chemical and pharmaceutical industries.For the ClER side,the state-of-the-art electrocatalysts for ClER are the so-called dimensionally stable anodes?DSAs?.Although many works mainly forced on the element doping for the traditional coating electrode,the researches about manipulation on electrodes surface morphology are rarely demonstrated.Moreover,all the GERs suffered from server "bubble effect",a phenomenon that the as formed gas bubbles stick to the flat electrode surface.Therefore,it is expected that developing nanostructured electrode with superaerophobic surface and low-adhesion for bubbles foe various GERs would be promising to improve the corresponding electrocatalystic performance.1?Nanoporous Fe₂Ni₂N NPA was prepared by converting NiFe-LDH under an NH3 atmosphere,which demonstrated its high activity as a bifunctional catalyst for overall water splitting in alkaline medium.Due to the unique material and structural advantages,the Fe₂Ni₂N NPA electrode presented excellent catalytic activity with a small onset overpotential?ca.200 mV for OER and 110 mV for HER?,low Tafel slope?34 mV/dec for OER and 101 mV/dec for HER?and prominent electrochemical durability.This kind of catalyst can be directly utilized as a catalyst for both anode and cathode with superior efficiency and strong robustness.These findings can inspire a variety of opportunities for designing other binary or trinary transition metal nitrides towards the full electrocatalytic splitting reaction of water,as well as in other electrochemical devices.2?Superaerophobic RuO₂@TiO₂ nanostructured electrode with low gas bubble adhesion force and large bubble CA was achieved by constructing nanoarray electrode combining hydrothermal growth with electrodeposition method.The superb performance of superaerophobic electrode exhibited superior ClER electrocatalytic activity and maintained much better working stability than the traditional RuO₂-TiO₂ coating and RuO₂@TiO₂ flat electrodes,which was attributed to accelerate gas bubbles leaving and minimize the negative effect caused by bubble adhesion.This successful demonstration not only further confrmed the conception of "superaerophobic electrode" in previous studies,but also could be usable for designing better electrode for chlor-alkali industrial electrodes.