Preparation And Properties Of Ru/Metal Oxide/Carbon Materials Composite Electrocatalysts

In recent years,hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)from water splitting,as a new type of green catalysis technology,has been widely used in the generation and storage of energy.Pt and RuO2 are used as benchmark catalysts for water splitting,but their wide application is limited due to their certain resource reserves and expensive price.Therefore,it is very necessary to find a catalyst with high catalytic activity and low price.In this paper,Ru/MoO2/CNTs and Ru/RuO2/WO3/CC electrocatalysts with high catalytic activity and high specific surface area were prepared through modified two-dimensional transition metal oxides by means of carbon supporter combination,surface modification,and morphology control.Powder X-ray diffraction,X-ray photoelectron spectroscopy,scanning electron microscopy,transmission electron microscopy,thermogravimetric analyzer and raman spectroscopywere were used to characterize the prepared catalysts.In an alkaline electrolyte,the catalytic performances of the prepared electrocatalysts were comparatively studied,and the electrocatalytic mechanism was further discussed through the results of characterization.The details are as follows:1.Firstly,using the annealing treatment,the mesh carbon nanotubes(CNTs)is generated.Then,molybdenum disulfide sheet supported by CNTs was prepared by hydrothermal method through adding molybdenum source and sulfur source.RuO2 was grown in situ on the above MoS2 nanosheets,and finally a series of Ru/MoO2/CNTs composite electrocatalysts were successfully synthesized via annealing.The results show that Ru nanoparticles with relatively uniform size were successfully deposed on the MoO2 flakes supported by CNTs.The performance of the electrocatalyst showed that the activity of the composite electrocatalyst was significantly improved after the addition of CNTs support.It exhibits the best HER performance with low overpotential of 16 mV at 10 mA cm-2 and 171 mV at 100 mA cm-2,which is superior to the Pt/C electrocatalyst.In addition,the catalyst shows little decay after 5000 cycles,indicating its strong stability.Therefore,it is proved that the Ru/MoO2/CNTs hybrid catalyst possesses good HER catalytic activity.The kinetics and mechanism of Ru/MoO2/CNTs electrocatalytic hydrogen production are deeply explored.2.Firstly,WS2 sheet supported on carbon cloth(CC)was synthesized via hydrothermal method,and Ru/RuO2/WO3/CC(RRWC)composite with hierarchical micro-nano structure was prepared by a solid-phase redox reaction method.Briefly,sheet-like ROWC precursors were obtained by sequentially loading WS2 nanosheets and RuO2 nanoparticles on carbon cloth,and were converted into RRWC hybrids by annealing under Ar atmosphere.The RRWC sample annealed at 450℃(RRWC-450)showed the best performance with a low overpotential of 31 mV for HER and a low overpotential of 261 mV for OER at a current density of 10 mA cm-2 in 1 M KOH.It has no obvious decay after 24 h for HER and 16 h for OER in the i-t test,respectively.At the same time,in the overall water splitting test,the RRWC-450 catalyst exhibited excellent overall water splitting potential and super stability.