Interface-engineered Co3S4/CoMo2S4nanosheets as efficient bifunctional electrocatalysts for alkaline overall water splitting.

Exploring bifunctional electrocatalysts with high efficiency, inexpensive, and easy integration is still the daunt challenge for the production of hydrogen on a large scale by means of water electrolysis. In this work, a novel free-standing Co3S4/CoMo2S4heterostructure on nickel foam by a facial hydrothermal method is demonstrated to be an effective bifunctional electrocatalyst for overall water splitting (OWS). The synthesized Co3S4/CoMo2S4electrocatalyst achieves ultralow overpotentials of 143 mV@10 mA cm-2for hydrogen evolution reaction (HER) and 221 mV@25 mA cm-2for oxygen evolution reaction (OER), respectively, in 1 M KOH. Moreover, it presents a greatly improved durability and stability under operando electrochemical conditions. When used as catalysts for OWS, the Co3S4/CoMo2S4-3//Co3S4/CoMo2S4-3 electrodes just need 1.514 V to make it to the current density of 10 mA cm-2. It is supposed that the introduction of heterogeneous interface between Co3S4and CoMo2S4could give rise to plentiful active sites and enhanced conductivity, and thus boost excellent catalytic performances. Moreover, the porous feature of free-standing nanosheets on nickel foam could benefits catalytic performances by accelerating charge transport and releasing bubbles rapidly. This work proposes a bifunctional catalyst system with the heterogeneous interface, which could be used in a sustainable green energy system.

Surface Modulation of Iron-doped MoS2 Nanosheets by Phytic Acid for Enhanced Water Oxidation.

Surface modulation and heteroatom doping are important approaches for boosting the electrocatalytic performances of MoS2 nanosheets. As a molecular electrocatalyst, the natural organic phytic acid (PA) offer attractive intermediate for oxygen evolution reaction (OER). Here, a surface modulation strategy is demonstrated through the decoration of PA onto the basal plane of iron (Fe)-doped MoS2 nanosheets supported on nickel foam (NF) for boosted OER activity. Experimental results indicate that the PA modification and Fe doping could effectively boost the charge transfer and mass transport during the OER process. Specially, PA2-Fe-MoS2 grown on NF (PA2-Fe-MoS2 /NF) exhibits excellent OER activity (218 mV@20 mA cm-2 ) and durability, even superior to RuO2 and many other previously reported OER catalysts. This natural organic molecule modification provides a facile strategy to designing low-cost and efficient electrocatalytic materials.