Abstract Electrochemical water splitting for hydrogen production is regarded as an important emerging energy conversion technology due to its broad application prospects, but its industrialization process is limited by the slow kinetics and high reaction energy barrier of the anodic oxygen evolution reaction (OER). Therefore, developing electrocatalytic materials with high activity and stability is crucial for the advancement of electrochemical water splitting technology. This study reported a Ce-doped cobalt sulfide catalyst encapsulated by an ultra-thin carbon layer via a MOFs-derived method. The catalyst achieved a low overpotential of 279 mV for the alkaline OER at 10 mA cm−2 for over 170 h. The high catalytic activity mainly stems from a dual optimization mechanism: (1) the introduction of rare earth element cerium into the lattice effectively optimizes the electronic structure of cobalt sulfide, significantly reducing the OER energy barrier; (2) the ultra-thin carbon layer on the surface constructs a conductive network and greatly improves the lifespan of the catalytic material. This strategy combining electronic structure regulation and surface engineering provides a new idea for the design of high-efficiency electrocatalysts for water splitting. Highlights <OrderedList> <ListItem> <ItemNumber>1.</ItemNumber> <ItemContent> <Emphasis Type="BoldItalic">The Ce–CoS</Emphasis><Emphasis Type="BoldItalic">x</Emphasis><Emphasis Type="BoldItalic">/NC nanocatalyst exhibited exceptional OER activity (279 mV overpotential at 10 mA</Emphasis> <Emphasis Type="BoldItalic">cm</Emphasis><Emphasis Type="BoldItalic">−2</Emphasis><Emphasis Type="BoldItalic">) and superior stability (170 hours at 10 mA cm</Emphasis><Emphasis Type="BoldItalic">−2</Emphasis><Emphasis Type="BoldItalic">) in alkaline media.</Emphasis> </ItemContent> </ListItem> <ListItem> <ItemNumber>2.</ItemNumber> <ItemContent> <Emphasis Type="BoldItalic">The outstanding performance of</Emphasis> <Emphasis Type="BoldItalic">Ce-CoS</Emphasis><Emphasis Type="BoldItalic">x</Emphasis><Emphasis Type="BoldItalic">/NC is attributed to the synergistic effect of two strategies: cerium reduces the reaction energy barrier by inducing electron migration within the material, thereby promoting oxygen evolution activity; meanwhile, the N-doped carbon layer serves as a protective shield to remarkably extend the catalytic lifespan</Emphasis>. </ItemContent> </ListItem> </OrderedList> Discussion Transition metal sulfides (TMSs) demonstrate exceptional application potential in the oxygen evolution reaction (OER) owing to their unique electronic configurations and superior electrical conductivity. However, the OER activity and stability of TMSs are severely compromised under continuously oxidative potential in alkaline media, which significantly limits their practical implementation. To address these challenges, we modified TMSs via a synergistic combination of ion doping and surface coating strategies, aiming to extend the catalytic lifespan. It also lays a robust foundation for the in-depth investigation of TMSs stability in future research. Graphical abstract

Ce-doped cobalt sulfide encapsulated by an ultrathin N-doped carbon layer for efficient water oxidation reaction

期刊论文
发表日期：

2026年3月3日

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Jia Lei,
Zongdeng Wu,
Boyuan Liu,
Jiayi Tang,
Junjie Shu,
Haiyan Jing,
Wu Lei,
Qingli Hao

摘要

Abstract

Electrochemical water splitting for hydrogen production is regarded as an important emerging energy conversion technology due to its broad application prospects, but its industrialization process is limited by the slow kinetics and high reaction energy barrier of the anodic oxygen evolution reaction (OER). Therefore, developing electrocatalytic materials with high activity and stability is crucial for the advancement of electrochemical water splitting technology. This study reported a Ce-doped cobalt sulfide catalyst encapsulated by an ultra-thin carbon layer via a MOFs-derived method. The catalyst achieved a low overpotential of 279 mV for the alkaline OER at 10 mA cm⁻² for over 170 h. The high catalytic activity mainly stems from a dual optimization mechanism: (1) the introduction of rare earth element cerium into the lattice effectively optimizes the electronic structure of cobalt sulfide, significantly reducing the OER energy barrier; (2) the ultra-thin carbon layer on the surface constructs a conductive network and greatly improves the lifespan of the catalytic material. This strategy combining electronic structure regulation and surface engineering provides a new idea for the design of high-efficiency electrocatalysts for water splitting.

Highlights

The Ce–CoS_x/NC nanocatalyst exhibited exceptional OER activity (279 mV overpotential at 10 mA cm⁻²) and superior stability (170 hours at 10 mA cm⁻²) in alkaline media.

The outstanding performance of Ce-CoS_x/NC is attributed to the synergistic effect of two strategies: cerium reduces the reaction energy barrier by inducing electron migration within the material, thereby promoting oxygen evolution activity; meanwhile, the N-doped carbon layer serves as a protective shield to remarkably extend the catalytic lifespan.

Discussion

Transition metal sulfides (TMSs) demonstrate exceptional application potential in the oxygen evolution reaction (OER) owing to their unique electronic configurations and superior electrical conductivity. However, the OER activity and stability of TMSs are severely compromised under continuously oxidative potential in alkaline media, which significantly limits their practical implementation. To address these challenges, we modified TMSs via a synergistic combination of ion doping and surface coating strategies, aiming to extend the catalytic lifespan. It also lays a robust foundation for the in-depth investigation of TMSs stability in future research.

Graphical abstract