High repetition rate ultrafast laser-structured nickel electrocatalyst for efficient hydrogen evolution reaction

Laser processing with high-power ultrashort pulses,which promises high precision and efficiency,is an emerging new tool for material structuring.High repetition rate ultrafast laser highlighting with a higher degree of freedom in its burst mode is believed to be able to create micro/nanostructures with even more variety,which is promising for electrochemical applications.We employ a homemade high repetition rate ultrafast fiber laser for structuring metal nickel(Ni)and thus preparing electrocatalysts for hydrogen evolution reaction(HER)for the first time,we believe.Different processing parameters are designed to create three groups of samples with different micro/nanostructures.The various micro/nanostructures not only increase the surface area of the Ni electrode but also regulate local electric field and help discharge hydrogen bubbles,which offer more favorable conditions for HER.All groups of the laser-structured Ni exhibit enhanced electrocatalytic activity for HER in the alkaline solution.Electrochemical measurements demonstrate that the overpotential at 10 mAcm−2 can be decreased as much as 182 mV compared with the overpotential of the untreated Ni(−457 mV versus RHE).