NiSe2 nanoparticles embedded in CNT networks: Scalable synthesis and superior electrocatalytic activity for the hydrogen evolution reaction

For the first time, NiSe2 nanoparticles embedded in CNT networks have been synthesized via spray-drying followed by a selenization process. The NiSe2/CNTs hybrid (NCH) delivers superior electrocatalytic performance for HER. It has a low onset potential of similar to 159 mV and a cathode current density of 35.6 mA cm(-2) at -250 mV vs RHE; more importantly, the Tafel slope has a very low value of 29 mV dec(-1), which is comparable to a platinum (Pt) catalyst; in addition, it is stable even after 1000 cycles. The superior HER performance of NCH is attributed to its unique structure, which is composed of ultrathin NiSe2 nanoparticles homogenously embedded in highly conductive and porous CNT networks. This not only provides abundant HER active sites, but also guarantees robust contact between the NiSe2 nanoparticles and the CNT networks. The present study provides new insights into the large-scale and low-cost synthesis of a highly effective and stable NiSe2-based electrocatalyst which could be extended to large-scale production of other non-precious metal hybrid catalysts with low cost, high efficiency and excellent stability.