Synthesis of CoAl-LDH nanosheets and N-doped graphene nanocomposite via Successive Ionic Layer Deposition method and study of their electrocatalytic properties for hydrogen evolution in alkaline media

Highlights: • Novel simple synthesis of CoAl-LDH/N-doped graphene nanocomposite via SILD method. • The CoAl-LDH/N-doped graphene nanocomposite formation of ultrathin nanocrystals with thickness of 3–5 nm. • The CoAl-LDH/N-doped graphene nanocomposite exhibits high HER electrocatalytic activity and electrochemical stability. -- Abstract: Here we introduce a new strategy for synthesis of layered double hydroxide CoAl-LDH nanosheets and N-doped graphene composite via Successive Ionic Layer Deposition (SILD) method as well as the study of their efficiency as electrocatalytic materials for hydrogen evolution reaction in alkaline media. The synthesis nanosheets were characterized by SEM, EDX, XRD, Raman, XPS and FTIR methods. Electrocatalytic characteristics of electrodes based on nickel foil and nanosheets synthesized via SILD method (50 cycles) have been studied in 1 M KOH solution by using techniques of polarization curves, cyclic voltammetry and chronoamperometry. The values of excess voltage at the current density of 10 m/cm² for CoAl-LDH and N-doped graphene nanocomposite were −415 and −365 mV, and Tafel slope was 53 mV/dec and 48 mV/dec, respectively. We report that CoAl-LDH composite containing N-doped graphene shows better electrocatalytic characteristics than CoAl-LDH without graphene and has high cyclic stability.