Molybdenum-doped Co3S4 nanoarrays as outstanding catalysts for overall water splitting

Developing cobalt-based electrocatalysts that can replace precious metals is significant for hydrogen production in water splitting, however, this is still a complex and demanding task. Here, 3D Mo-doped Co3S4 nanosheet arrays are anchored to nickel foam (Mo–Co3S4/NF) through one-step hydrothermal vulcanization of the Co-MOF precursor. The best electrocatalytic performance has been achieved by optimizing the heteroatom content. The Mo–Co3S4-0.1/NF just needs 154 mV at a current density of 10 mA cm−2 for the HER and 320 mV with 50 mA cm−2 for the OER, respectively. Meanwhile, Mo–Co3S4-0.1/NF as both the cathode and anode in an integrated cell only required 1.52 V to create a current density of 10 mA cm−2 without attenuation for 22 h. Doped Mo heteroatoms can optimize the electron configuration and morphology to accelerate the mass charge transfer of Co3S4/NF. This work confirms that the performance of catalytic materials can be enhanced by introducing heteroatoms.