Single atom tungsten doped ultrathin ?-Ni(OH)₂ for enhanced electrocatalytic water oxidation.

ABSTRACT: Electrocatalytic water oxidation is a rate-determining step in the water splitting reaction. Here, we report one single atom W⁶⁺ doped Ni(OH)₂ nanosheet sample (w-Ni(OH)₂) with an outstanding oxygen evolution reaction (OER) performance that is, in a 1?M KOH medium, an overpotential of 237?mV is obtained reaching a current density of 10?mA/cm². Moreover, at high current density of 80?mA/cm², the overpotential value is 267?mV. The corresponding Tafel slope is measured to be 33?mV/dec. The d⁰ W⁶⁺ atom with a low spin-state has more outermost vacant orbitals, resulting in more water and OH^- groups being adsorbed on the exposed W sites of the Ni(OH)₂ nanosheet. Density functional theory (DFT) calculations confirm that the O radical and O-O coupling are both generated at the same site of W⁶⁺. This work demonstrates that W⁶⁺ doping can promote the electrocatalytic water oxidation activity of Ni(OH)₂ with the highest performance.

SUBMITTER: Yan J 

PROVIDER: S-EPMC6517434 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature