Synergetic pseudocapacitive sodium capture for efficient saline water desalination by iron oxide Hydroxide-Decorated palladium nanoparticle anchored 3D flowerlike molybdenum sulfide

Abstract

Capacitive deionization (CDI)-based saline water desalination presents an admirable alternative for sustainable freshwater production. However, the lack of robust electrode materials impedes its wide application. Herein, a three-dimension (3D) heterostructured iron oxide-hydroxide-incorporated palladium nanoparticle-anchored molybdenum disulphide (FeOOH/Pd/MoS2) hybrid constructed by the two-step spontaneous interfacial redox reactions is reported as efficient Faradaic CDI electrode materials for desalination application. The FeOOH/Pd/MoS2 hybrid electrode delivers a superior desalination capacity of 41.1 mg g−1 in a 500 mg L-1 NaCl solution, along with impressive cycling stability and a high capacitive contribution of 80 % at a rate of 1 mV s−1. The synergetic pseudocapacitive removal process is thoroughly clarified by ex-situ XPS characterizations. Experimental analysis and density functional theory calculations reveal that the bi-component participation of FeOOH and Pd can efficiently tailor the electronic structure of MoS2, leading to the reinforcing electronic conductivity toward the promoted Na+ capture feature. Moreover, the hybrid electrode manifests outstanding removal efficiencies up to 91.25 % for diverse heavy metal ions (i.e., Pb2+, Cd2+, Cu2+, Ni2+, and Cr3+), demonstrating its great prospects for low-concentration wastewater purification. This work supplies an ingenious avenue for the rational design of heterostructured MoS2 Faradaic electrodes for advanced CDI desalination.