Executive Summary : | Constantly rising global energy (E) demands coupled with extreme reliance on fossil fuels as well as increasing global warming have led researchers to urgently focus on developing clean, sustainable, and renewable E production-storage technologies e.g. overall H₂O splitting (OWS) devices, metal–air batteries, and fuel cells. Electrocatalytic H₂O splitting through oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is regarded as promising means to generate eco-friendly fuels. However the sluggish kinetics and large overpotentials (η) of both OER/HER are the key bottlenecks for large-scale implementation of H₂O electrolysis which necessitates the development of efficient electrocatalysts (ECs) to accelerate the reaction rate. Nowadays, various ECs were evaluated but most of the alternative ECs show their OER activity in alkaline electrolyte while HER in acidic electrolyte. Thus various pH requirements limit their practical applications. Therefore it will be of great fortunate if a commercially feasible single earth-abundant EC efficiently promotes both OER/HER in identical electrolyte under similar pH.
Transition metal oxides (TMOs) e.g. Mn, Fe, Co or Ni not only have abundant reserves and cost-effectiveness but also show a huge potential in E storage-conversion field due to reversible redox reactions on catalyst surface. Among them, Mn has attracted noteworthy attention due to its superior electrochemical properties possessing highest stable valency (+7) as well as different stable oxidation states (+2 to +7) which makes it highly susceptible to undergoing various electronic transitions enhancing reactive intermediates adsorption. But Mn-based ECs exhibit poor conductivity, low surface area, and easy aggregation resulting in unsatisfactory bifunctional activity which fortunately can be mitigated to efficient bifunctionality by compositing with other TMs/TMOs. The coexistence of different M/MOs boosted their OER/HER activities owing to their strong synergistic effect. More interestingly, this combination with Ru-based material is an effective approach for improving the catalytic activity benefiting from its outstanding catalytic properties, robust anti-corrosion ability, and lower price compare to noble metal family.
This project targets the development of highly efficient mixed valence (MV) Ru(delta+)-fabricated Mn-based H₂O splitting bifunctional ECs. The novelty of this project lies on surface engineering of MV nanostructures expressing strong synergistic effect which can offer greater number of active sites facilitating OH−/H₂O adsorption for OER/HER, respectively during OWS as well as provide active heterointerface during electrolysis. Cheaper and more sustainable ECs are expected with abundant active sites that can be manipulated to modulate reagent binding. Here the aims are at the frontier of materials research and it will help in realizing the full potential of ECs for future E production. |