Studies On The Syntheses And Electrochemical Water Splitting Performances Of Heterogeneous Materials Modified Transition Metal Catalysts

The over-reliance on traditional energy in the development of human society inevitably leads to the rapid decline of global energy reserves.Hydrogen is considered to be the cleanest and most ideal energy to replace non-renewable fossil fuels.Electrocatalytic water splitting to produce hydrogen and oxygen is considered to be one of the most promising and attractive strategies to convert solar energy,wind energy and electric energy into chemical energy.In the water electrolysis system,the energy conversion efficiency mainly depends on the activity of cathodic and anodic catalysts.Generally speaking,precious metal-based catalysts?such as Pt,IrO2,RuO2?show the highest activity,but scarcity and high price hinder their wide application.Because the transition metal is rich in reserves and the catalytic activity of some materials is similar to that of precious metal catalysts,a lot of studies have been carried out on transition metal catalysts.Herein,we have researched and innovated transition metal catalysts to improve electrocatalytic activity.The specific research results are as follows:?1?Ultrathin Ni-Co-B nanosheets have been vertically aligned on reduced graphene oxide as exceptionally efficient oxygen evolution reaction electrocatalyst for the first time.Controlled experiments indicate the critical role of reduced graphene oxide in guiding the formation of Ni-Co-B nanosheet.The catalyst affords a current density of 10 mA cm^-2at low overpotential of 280 mV,which is better than most of metal boride catalysts reported to date.Stable current output is maintained at 20 mA cm-2 for at least 60 h.?2?Ultrafine Pd nanoparticles are electrodeposited upon hydrothermally grown NiFe layered double hydroxide?NiFe LDH?on nickel foam to pursue improved electrocatalysis bifunctionality.The introduced Pd induces more active sites,strong electric interaction,and enhanced charge transfer,thus leading to substantially improved catalytic activity for water electrolysis.The optimal Pd-Ni Fe LDH exhibits impressive catalytic activity,affording a current density of 10 mA cm^-22 at low overpotentials of 156m V for the OER and 130 mV for the HER,respectively.The two-electrode electrolyzer assembled with Pd-NiFe LDH achieves an ultralow cellpotential of 1.514 V at 10 mA cm^-22 for overall water splitting,superior to those of most of the previous bifunctional electrocatalysts in alkaline media.?3?We present the exploratory research on fabricating heterostructures of NiCo hydrogen carbonate(Ni_0.6Co_0.4?HCO₃?₂)with Pt nanoparticles supported on nickel foam for active hydrogen evolution reaction?HER?in alkaline water.The coupling of Ni_0.6Co_0.4?HCO₃?₂ with Pt moderates the hydrogen adsorption energy for improved intrinsic activity and enhanced reaction kinetics.The hetero-interface effect provides extrinsic benefits of accessible active sites and accelerated charge transfer for advanced HER performances.Therefore,the developed sample exhibits excellent HER activity(56m V at 10 mA cm^-2)and stable durability.Notably,the mass activity of Pt in Pt-Ni_0.6Co_0.4?HCO₃?₂ is even higher than that of Pt/C.