Rational development of molecular earth-abundant metal complexes for electrocatalytic hydrogen production

For public health and environmental protection reasons, there is an urgent need to replace traditional fossil fuels with clean and renewable sources. Electrochemical splitting of water has the potential to produce clean hydrogen as a possible solution to global energy problems. This review article introduces the rational design of molecular metal complexes based on earth-abundant metals for electrocatalytic hydrogen production in water or water-organic media. Emphasis is placed on providing insight into structure-function relationships in catalytic properties for future ligand and catalyst design. Electrocatalytic hydrogen evolution by molecular metal complexes of Fe, Ni, Co and Cu is briefly discussed to provide insight into catalyst design and structure-function correlations in hydrogen catalysis.