Three-dimensional hierarchical nanoporous (Mn,Ni)-Doped Cu2S architecture towards high-efficiency overall water splitting

Dealloying technique is an important approach to design porous structures and highly active catalysts. In this work, monolithic nanoporous (Mn,Ni)-doped Cu2S skeletons with controllable composition and tunable porosity are synthesized via dealloying and sulfuration technique. The as-prepared S-np-Mn70Cu29Ni1 electrode exhibits outstanding catalytic performance toward HER and OER in 1.0 M KOH solution, which drives high current density of 50 mA cm(-2) at the overpotentials of 136 and 317 mV respectively. The excellent catalytic performance is attributed to the unique three-dimensional interconnected bicontinuous nanoporous architecture, which not only exposes high-density catalytic active sites, but also accelerates electron/mass transfer between catalyst surface and electrolyte. Density functional theory (DFT) calculations also reveal that (Mn,Ni)-doped Cu2S matrix can accelerate water adsorption/dissociation and optimize adsorption desorption energetics of H intermediates, thus improving the intrinsic HER activity of nanoporous Cu2S electrocatalysts. Meanwhile, an alkaline water electrolyzer is constructed with the S-np-Mn70Cu29Ni1 electrode as anode and cathode respectively, depicting remarkable performance in water electrolysis. In the light of advantages such as adjustable composition and tunable porosity in alloying-dealloying process, it offers a new vision for tuning the porosity and catalytic activities of transition metal sulfides and other active catalysts. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Dealloying technique was used to synthesize monolithic nanoporous (Mn,Ni)-doped Cu2S skeletons with controllable composition and tunable porosity. The resulting electrode exhibited outstanding catalytic performance in alkaline solution, and showed potential applications.