CoFe-Layered Double Hydroxide Needles on MoS<sub>2</sub>/Ni<sub>3</sub>S<sub>2</sub> Nanoarrays for Applications as Catalysts for Hydrogen Evolution and Oxidation of Organic Chemicals
Chenguang Li, Hongyou Pang, Rong Xu, Jun Fan, Enzhou Liu, Tao Sun
Abstract
Electrochemical water splitting prompted by organic molecules presents a competitive prospect for implementing energy-efficient hydrogen evolution and alleviating organic-rich water pollution. In this work, we fabricated a heterojunction of CoFe-layered double hydroxide (CoFe LDH) needles on MoS 2 /Ni 3 S 2 /nickel foam (NF) nanoarrays (CoFe LDH/MoS 2 /Ni 3 S 2 /NF) by forming a Schottky interface and a p–p heterojunction interface. The prepared CoFe LDH/MoS 2 /Ni 3 S 2 /NF exhibits superior electrocatalytic activities with low potentials to drive 50 mA cm –2 for the hydrogen evolution reaction (HER, 0.098 V vs the reversible hydrogen electrode (RHE)), oxygen evolution reaction (OER, 1.507 V vs RHE), urea oxidation reaction (UOR, 1.460 V vs RHE), and ethanol oxidation reaction (ETOR, 1.484 V vs RHE). Meanwhile, the electrode can maintain robust stability in these reactions. The enhanced electrocatalytic activities result from the increased active sites and the acceleration of charge transfer caused by the built-in electric fields. Moreover, the prepared catalyst also exhibits remarkable catalytic performance in two-electrode electrocatalytic systems of KOH, KOH assisted by urea, and KOH assisted by polylactic acid. This work offers a rational method for designing efficient electrocatalysts via combining heterojunctions to effectively generate hydrogen energy and treat organic pollutants.