Hydrogen has been considered as an efficient clean energy since it may be the alternative to fossil fuels. Large-scale production and effective storage of hydrogen are important research topics.

The electrolysis of water is an environmentally friendly technique for hydrogen production. However, Pt-based materials that are used as catalysts for hydrogen evolution reaction (HER) have been severely restricted for the industrial production because of the high cost of noble-metal Pt. Lowering the overpotential (η), constructing and preparing the high-efficient non-noble metal electrocatalysts should be addressed to improve the HER performance.

Researchers have reported abundant non-noble metal and metal-free HER catalysts and made an important breakthrough. It is noteworthy that the transition metal sulfides and carbides show HER electro-catalytic activities. The complicated techniques, high cost and low yield for the most of these materials, have caused the difficulties in industrialization. Thus, searching for a cheap and effective electrocatalyst has become a research hotspot.

Recently, a research team led by Prof. YU Shuhong at the University of Science and Technology of China of Chinese Academy of Sciences and Prof. LAN Yaqian at Nanjing Normal University have prepared the phosphorus doped porous carbon coated molybdenum dioxide-reduced graphene oxide hybrid material (denote as MoO₂@PC-RGO), which is prepared by carbonizing polyoxometalate-based metal-organic frameworks/graphene oxide composite (POMOFs/GO) precursors at a relatively low temperature.

POMOFs have the advantages of both MOFs and POMs, in which MOFs could provide regular carbon array derived from the ligands and POMs could function as the Mo and P source. The agglomeration of MoO₂ can be avoided by confining the carbon skeleton, which is conducive to prepare the small-sized and uniform nanomaterials.

These nanoscale materials can improve the activities and stabilities of HER catalysts. The MoO₂@PC-RGO nanocomposite displays an excellent HER activity in acidic solution approaching that of commercial 20% Pt/C. So far, it is one of the best high performance catalysts among the reported non-noble metal catalysts for the HER. It can be synthesized in quantity for industrial production that is expected to replace the commercial Pt-based catalysts.

The work was published in Angewandte Chemie Inernational Edition.

Preparation process of the MoO₂@PC-RGO nanocomposite used as electrocatalyst for the HER. (Image by USTC)