Bimetallic Ni 2− x Co x P carbon nanofibers network: solid–solution alloy nano-architecture as efficient electrocatalyst for water splitting

The design of efficient and cost-effective electrocatalysts with steady capability has attracted much attention in the field of water splitting in recent years. In this paper, Ni 2− x Co x P/CNFs ( x = 0, 0.67, 1, 1.33 and 2), where the ultrafine Ni 2− x Co x P nanoparticles are encapsulated in carbon nanofibers, are synthesized using a facile electrospinning method followed by thermal treatment. The space confinement by the carbon matrix with a high length-to-diameter ratio (>1000) and excellent conductivity produces ultrafine Ni 2− x Co x P with abundant active sites. Moreover, engineering of Ni 2− x Co x P/CNFs can induce electronic modulation and consequently optimize the adsorption of H on the electrocatalyst surface to promote HER performance, as well as to reduce the energy barrier of the potential-limiting step. The optimal Ni 2− x Co x P/CNFs exhibit superior electrocatalytic performance with low overpotentials of about 271 mV for OER and about 118.76 mV for HER at 10 mA cm −2 with excellent long-term durability in 1.0 M KOH solutions, performing as one of the best non-noble-metal electrocatalysts so far. Furthermore, the two-electrode electrolyser delivers a high efficiency and remarkable long-term durability for overall water splitting. This work provides new insights into the development of nanofiber-structured electrocatalysts.