The sluggish kinetics of oxygen evolution reaction (OER) is the main bottleneck for the electrocatalytic water splitting to produce hydrogen (H2), and the by‐product is worthless O2. Therefore, designing a thermodynamically favorable oxidation reaction to replace OER and coupling with value‐added product generation on the anode is of significance for boosting H2 generation under low electrolysis voltage. Herein, cobalt hydroxide@hydroxysulfide nanosheets on carbon paper (Co(OH)2@HOS/CP) are synthesized as bifunctional electrocatalysts to facilitate H2 production and convert methanol to valuable formate simultaneously. Benefiting from the influences/changes on the composition, surface properties, electronic structure, and chemistry of Co(OH)2, the as‐obtained electrodes exhibit very high selectivity for methanol to value‐added formate oxidation (MFO) and boost electrocatalytic performance with low overpotential of 155 mV for MFO and 148 mV for hydrogen evolution reaction at a current density of 10 mA cm−2. Furthermore, the integrated two‐electrode electrolyzer drives 10 mA cm−2 at a cell voltage of 1.497 V with united 100% Faradaic efficiency for anodic and cathodic reaction and continuous 20 h of operation without obvious decay. The electrocatalytic hydrogen production with the assistance of alternative oxidation by the robust electrocatalyst can be further used to realize the upgrading of other organic molecules with less energy consumption.

The increasing need for clean and sustainable energy inspires researchers to explore low-cost nonprecious metal electrocatalysts for advanced energy storage and conversion. Herein, we develop a reactive template route to fabricate a high-efficiency oxygen reduction reaction (ORR)/oxygen evolution reaction (OER)/hydrogen evolution reaction (HER) trifunctional electrocatalyst (CoFe/NH-C NS) via pyrolyzing the mixture containing CoFe-layered double hydroxide@glucosaminoglycan (CoFe-LDH@p-Glu) and urea/dicyandiamide. In this strategy, the CoFe-LDH not only provides a well-defined two-dimensional template to form carbon NSs but also employs a well-distributed CoFe precursor to form uniform CoFe nanoparticles (NPs). Such a synthetic strategy has been demonstrated effective to controllably fabricate the special nanostructure with metal NPs embedded in N-doped carbon NSs and favorable exposure of active sites, leading to a strong synergistic effect between CoFe and N-doped carbon NSs and abundant electrocatalytic active sites for energy electrocatalysis. CoFe/NH-C NS exhibits superior ORR performances to Pt/C with more positive half-wave potential (844 mV for CoFe/NH-C NS vs 832 mV for Pt/C), longer stability, and better methanol tolerance in alkaline conditions. Furthermore, CoFe/NH-C NS displays an identical current density to commercial RuO2 at 1.8 V (vs RHE) toward OER and a remarkable electrocatalytic property toward HER in alkaline conditions. This work presents fresh strategies for the design and fabrication of high-performance carbon-based energy materials.

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Developing earth-abundant, highly active, and durable electrocatalysts for the oxygen evolution reaction (OER) is very important for many renewable energy conversion processes. Herein, we report a novel OER electrocatalyst of NiCo layered double hydroxide@NiCo-hydroxysulfide (NiCo-LDH@HOS) nanosheet arrays, which are prepared by a rapid room-temperature sulfurization of the surface of NiCo-LDH nanosheets grown on Ni foam. The surface sulfurization exerts important influences/changes on the structure, composition, surface properties and chemistry of NiCo-LDH. After surface sulfurization, the resulted NiCohydroxysulfide layer armor improved electrical conductivity and chemical resistance to alkaline electrolyte, delivers a stable current density of 10.0 mA cm −2 at a low overpotential of 293 mV in 0.1 M KOH solution, maintaining high stability during a 62 h test. The achieved enhanced oxygen evolution activity and improved durability are superior to those of NiCo-LDH nanosheets and benchmark commercial RuO 2 . This example of NiCo-LDH@HOS obtained via surface sulfurization with enhanced OER electrocatalysis performance, highlights an important strategy to fabricate high-performance metal hydroxide/hydroxysulfides heterostructured catalysts for OER and other electrochemical storage and conversion progress.