Just add water to split water: ultrahigh-performance bifunctional electrocatalysts fabricated using eco-friendly heterointerfacing of NiCo diselenides

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2020-06, Vol.8 (24), p.1235-1244
• Main Authors: Chen, Dongliang, Xu, Zhenmiao, Chen, Wei, Chen, Guangliang, Huang, Jun, Song, Changsheng, Li, Chaorong, Ostrikov, Kostya (Ken)
• Format: Article
• Language: English
• Subjects: Catalysts; Clean energy; Cobalt; Current density; Decay; Electrocatalysts; Electrochemistry; Electrolytes; Hydrogen evolution reactions; Hydrogen-based energy; Hydroxides; Intermetallic compounds; Mathematical analysis; Nickel; Oxygen evolution reactions; Polarization; Reaction kinetics; Selenides; Splitting; Structural stability; Tafel slopes; Theoretical analysis; Water splitting; X ray photoelectron spectroscopy
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d0ta02121k

Electrochemical water splitting is one of the most promising ways for clean hydrogen energy production. Along with using earth-abundant, atomically engineered catalysts that are highly active and stable, clean, chemical-waste-free catalyst production-using minimum resources-is a major hurdle toward achieving zero-carbon-emission commercial operations. Herein, we propose a clean way to fabricate NiSe 2 -CoSe 2 on nickel-cobalt foam (NCF) using pure water for the in situ sprouting of NiCo layered double hydroxide (LDH) precursors. The excellent electrocatalytic activity for overall water splitting in alkaline electrolytes is highlighted by the overpotentials of NiSe 2 -CoSe 2 /NCF for delivering current densities of 10 and 400 mA cm −2 ( j 10 and j 400 , respectively) at only 24 and 257 mV for hydrogen evolution reaction (HER) and 250 and 346 mV for oxygen evolution reaction (OER), as well as the fast reaction kinetics affording small Tafel slope values of 24 (HER) and 48 (OER) mV dec −1 , respectively. NiSe 2 -CoSe 2 /NCF exhibits excellent electrocatalytic performance and structural stability, evidenced by the unchanged polarization curve after 10 4 cycles of CV tests and low decay of high current density ( j 100 ) after 100 h of HER and OER measurements. Theoretical analysis revealed that the Co atoms dispersed on the heterointerfaces between the NiSe 2 and CoSe 2 phases act as the electrocatalytic sites. Using eco-friendly water-based in situ sprouting, 2M (M = Ni, Co) selenide nanosheets are fabricated. The 2M selenide exhibits high HER (24 mV at j 10 ) and OER (346 mV at j 400 ) performances, including a low cell overpotential of 1.69 V at j 100 .