In the face of the growing demand of energy worldwide and the unabated negative environmental impacts of fossil fuels, alternative and greener energy sources are critically important. Hydrogen, in particular, has long been considered as one of the most promising clean, renewable energy sources to meet these challenging problems. However, the range of applications of hydrogen as fuel has been hampered by the lack of sustainable and efficient catalysts that can effectively generate it from water (i.e., a sustainable hydrogen source) and by the scarcity of sustainable catalysts that enable its utilization in fuel cells. This can be exemplified by the fact that noble metal-based catalysts such as Pt and Ir still remain the leading catalysts for such conversions, even though their widespread applications are limited by their low earth-abundance and high cost. Hence, developing sustainable (electro) catalysts for many of these reactions is currently regarded as one of the ‘Holly Grails’ in catalysis and renewable energy research alike. To address these burgeoning issues, Professor Tewodros Asefa and his co-workers, namely Dr. Xiaoxin Zou, Mr. Xiaoxi Huang, Dr. Anandarup Goswami, Dr. Rafael Silva and Dr. Bhaskar Sathe, and others in the group, have recently been pursuing the development of carbon-based, noble metal- or metal-free nanomaterials, composed of inexpensive and earth-abundant elements that can catalyze reactions in fuel cells as well as the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER)—the reactions needed for water splitting into hydrogen (and oxygen).
The group’s recent effort led to the discovery of Co-embedded, heteroatom-doped carbon nanosystems (i.e., sustainable materials) that can effectively catalyze HER with unprecedented high electrocatalytic activity, or with comparable/better catalytic efficiency as/than platinum, at all pH values. This finding, defying the conventional paradigms that only platinum or other noble metals are deemed the best catalyst for, is remarkable in the current state-of-the-art in catalysis.1,2 Efficient electrocatalysis of HER and OER by such inexpensive, non-precious materials or heteroatom-doped nanocarbons at all pH values could be not only a ‘game-changer’ in the field, but also motivational for the development of other metal-free or noble metal-free nanosystems as catalyst for renewable energy and other applications. Moreover, the work could be expected to stir up fundamental studies worldwide to unravel how exactly such systems catalyze such fascinating yet difficult reactions.