Towards a new avenue for rapid synthesis of electrocatalytic electrodes via laser-induced hydrothermal reaction for water splitting

Electrochemical production of hydrogen from water requires the development ofelectrocatalysts that are active,stable,and low-cost for water splitting.To address these challenges,researchers are increasingly exploring binder-free electrocatalytic integratedelectrodes (IEs) as an alternative to conventional powder-based electrode preparation methods,for the former is highly desirable to improve the catalytic activity and long-term stability for large-scale applications of electrocatalysts.Herein,we demonstrate a laser-inducedhydrothermal reaction (LIHR) technique to grow NiMoO4nanosheets on nickel foam,which is then calcined under H2/Ar mixed gases to prepare the IE IE-NiMo-LR.This electrode exhibits superior hydrogen evolution reaction performance,requiring overpotentials of 59,116 and143 mV to achieve current densities of 100,500 and 1000 mA·cm-2.During the 350 h chronopotentiometry test at current densities of 100 and 500 m A·cm-2,the overpotentialremains essentially unchanged.In addition,NiFe-layered double hydroxide grown on Ni foam is also fabricated with the same LIHR method and coupled with IE-NiMo-IR to achieve water splitting.This combination exhibits excellent durability under industrial current density.The energy consumption and production efficiency of the LIHR method are systematicallycompared with the conventional hydrothermal method.The LIHR method significantly improves the production rate by over 19 times,while consuming only 27.78%of the total energy required by conventional hydrothermal methods to achieve the same production.

Solidification and heat transfer of molten steel slag particles during air quenching process

In order to effectively utilize the resources and energy of molten steel slag,the variation of precipitation phase and specific heat of air quenched steel slag(AQSS)particles during continuous cooling process was investigated by FactSage and thermogravimetry differential scanning calorimetry.The cooling and solidification process of molten AQSS particles was simulated by Fluent.The microstructure changes in AQSS particles in solidification process were analyzed using an ultrahigh temperature laser confocal microscope and a scanning electron microscope.The results indicated that in the cooling process of molten AQSS particles,the precipitation of Ca_(2)Fe_(2)O_(5) resulted in the largest change of specific heat.Under the condition of slow cooling,the cooling rate is more obviously affected by specific heat.When the initial air velocity was 300 m s^(-1),there was the highest temperature difference in AQSS particles during cooling process.What is more,the compactness of the boundary region of AQSS particles was obviously better than that of its central region.