Combinatorial approaches for efficient screening of multicomponent photocatalysts and fuel cell catalysts

Environmental issues and fossil fuel demands have propelled renewable energy research and development. Photocatalytic systems are inspired by artificial photosynthesis, which is capable of converting solar energy into chemical energy. Fuel cells, on the other hand, hold great potential for direct conversion of chemical energy into electricity. A rational combination of photocatalytic systems and fuel cells can effectively convert, store and utilize solar energy as compared with hybrid solar cell–battery systems. The critical issues for both the systems are to discover suitable and low-cost catalysts for chemical conversion with high efficiency. In general, catalysts involved with several synergistic components and an optimal recipe for each constituent should be derived. Traditional methods were based on pure empirical and trial-error testing, which are time consuming and labor intensive. Alternative method that can screen catalysts rapidly could be of great importance. In this mini review, preparation of sample arrays with various compositions and libraries suitable for combinatorial characterization is discussed. Next, the focus is on discussing several methods including scanning mass spectrometry, pH imaging and scanning electrochemical microscopy for efficient screening in serial. Successful implementation of these approaches has a potential to open up opportunities for identification and commercialization of efficient solar energy–harvesting catalysts.