Comprehensive overview of polyoxometalates for electrocatalytic hydrogen evolution reaction

Electrocatalytic water splitting via hydrogen evolution reaction (HER) from renewable energy sources is an attractive alternative to produce hydrogen, but it still encounters the limitations of large-scale applicability of Pt-based electrocatalysts. Therefore, abundant efforts have been devoted to design and fabricate highly efficient and stable noble-metal-free electrocatalysts to replace the expensive Pt-based electrocatalysts. Recently, polyoxometalates (POMs) and their derivatives have been proven to provide plentiful opportunities for designing and fabricating highly efficient and stable noble-metal-free HER electrocatalysts with controllable catalytic active sites and well-defined nanostructures. In this review, recent advances on coordination structures and HER performances of POMs-contained composites and POMs-derived transition metal carbides, chalcogenides, phosphides, nitrides and other electrocatalysts have been discussed.