Research Projects

For practical and large scale hydrogen production as a potential source of renewal energy, it is essential to minimize the overpotential for the gas evolution reactions. In this relevance, various types of catalysts are introduced to accelerate electron transfer process for improving electrochemical and photoelectrochemical gas evolving processes, however there are several other important factors that requires careful attention to improve overall water splitting performance. For example, the unavoidable adhesion of produced hydrogen of oxygen gas bubbles on the electrode creates a complex gas–liquid–solid interface and temporality isolates catalytically active sites from access of electrolytes. These adhered gas bubbles need to grow big (in milimeter scale) enough for generating buoyancy force to compensate the bubble adhesion force at electrode surface for its detachment. Thus, repetitive adhesion of gas bubble to the electrode surface, compromise the gas evolution reactions by blocking active catalytic sites and thereby increasing concentration overpotential because of poor mass transport. Moreover, the repetitive detachment of strongly adhered bubbles imposed mechanical sheer stress and compromising its stability for electrochemical performance because of its delamination. To address this challenge, design of coatings that extremely repels bubbles and widely recognized as supeaerophobic appear as a promising tool for early detachment of produced gas from electrode to maintain access of electrolyte unperturbed. However, most of such coatings are derived from electrically insulating material, and their deposition results in compromise of an available electrochemically active surface area, and so affecting gas evolving reaction performance. In addition to this, oil or oily substance have inherent tendency to attached on solid underwater condition. This phenomenon is likely to irreversibly block the catalytically active sites, and thus, it is important to design underwater superoleophobic coating to prevent oil attachment during water splitting process in oil-contaminated waste water from industries or polluted open water sources. While this, microenvironments for gas evolving reactions significantly influence the reaction performances. For example, in a coated electrode, oligoethylene-glycol moiety improves hydrogen evolution reaction kinetics by providing a cationic microenvironment to the electrode surface because of its high affinity for potassium ions. But, customization of existing catalysts to achieve such favourable electrochemical microenvironment is a difficult task. On the other side, the design of an electrically conductive superaerophobic coating is rare. But, to maximize the performance of a catalyst, it is important to develop a universal coating that would be 1) electrically conductive, 2) extremely bubble repellent and oil-repellent underwater and 3) having favourable microenvironment for electrochemical or photoelectrochemical water splitting. Here, we are aiming to introduce different strategies to introduce electrically conductive superaerophobic and underwater superoleophobic coatings decorated with desired ionic environments for improving both hydrogen and oxygen evolution reactions (HER and OER), where electrical conductivity of the coating improves available catalytically active surface area, superaerophobicity promotes early detachment of gas bubbles and maintain nearly unperturbed access of electrolytes and customized ionic environment around electrode facilitates electron transfer process for faster kinetics. Further, association of standard and low cost catalysts for electrochemical and photoelectrochemical HER and OER with such universal coating is likely maximize their performance for overall water splitting. Certainly successful design of such strategy would likely to provide an affordable avenue for water splitting even using oil-contaminated aqueous solution.