Eletrocatalytic And Photocatalytic Performance Of Nickel Based Transition Metal Sulfides For Water Splittung

Electrocatalytic water splitting and photocatalytic water splitting are promising and attractive methods for the production of H2 and O2.Efficient cathode and anode catalysts are crucial for water splitting.This paper mainly concerns about the structural design of bifunctional catalyst materials,including the influence of catalysts on the performance of the photoelectrochemical HER and OER.A MoS2 on Ni3S2 nanorod array on Ni foam was firstly fabricated.Then followed by electrochemical deposition approach in which MoS2/Ni3S2/Ni foam is decorated with CoS.The as-synthesized catalysts hybrid not only endows the ease transport of electrons along Ni3S2 nanorods to Ni foam,but also accommodates maximal exposure of active edge sites to the reactants through hierarchical CoS and MoS2 nanosheets.Specifically,at 10 mA cm-2,the CoS-MoS2/Ni3S2/NF possesses the low overpotentials of 85 and 225 mV in 1.0 M KOH for HER and OER,outperforming most of the current non-noble electrocatalysts.When the current density is 10 mA cm-2 in electrolytic water with two-electrode system,the cell voltage is only 1.62 V.In this work,hierarchical MoO3 nanosheets covered Ni3S2 nanoarrays on Ni foam was fabricated and then followed by a facile electrochemical deposition.CdS thin layer is electrodeposited on the hydrangea-like MoO3/Ni3S2 structure and forms a conifer-like morphology.Ultrathin CdS layer modifying MoO3/Ni3S2 hierarchical nanoarray on Ni foam exhibits ultrahigh elctrocatalytic activity with a overpotential of 30 mV and 192mV at-10 mA cm-2 towards HER and OER,outperforming most of the current non-noble electrocatalysts.And the performance of electrocatalytic hydrogen evolution is similar to Pt/C.When the current density is 10 mA cm-2 in electrolytic water with two-electrode system,the cell voltage is only 1.58 V.Due to the synergistic effects from easy electron transfer among CdS,MoO3 and Ni3S2/NF and structure.Heterogeneous semiconductor thin films were fabricated using n-type CdS,p-type MoO3 and n-type Ni3S2 to constructe Z-scheme systems.Photoelectrochemical measurements show that CdS-MoO3/Ni3S2/NF is an efficient electrocatalytic and photoelectrocatalytic material.