The Synthesis And Electrochemical Performance Of Ru-based Nanomaterials

In this paper,Ru-based nanomaterials were successfully prepared by thermal reduction of metal precursors methods and applied to alkaline hydrogen evolution reaction?HER?and nitrogen reduction reaction?NRR?.The main contents of the exploration are as follows:?1?The development of electrocatalytic HER is in full swing,but how to reduce costs while improving activity and stability is still the most challenging task.This chapter,RuPdM?M=Ni,Co,Fe?ultrathin nanosheets?NSs?alloys were synthesized by one-step method and applied to the research of alkaline HER electrocatalysis.The experiment data show that the optimized trimetal Ru₃₈Pd₃₄Ni₂₈ultrathin NSs has an overpotential of only 20 mV vs.RHE at a current density of 10mA cm^-2,and its mass activity reaches 6.15 A mg^-1_{nobles metals} at-0.07 V vs.RHE.It can be compared with the currently reported Pt-based electrocatalysts with the highest mass activity.The durability test also proves that the electrocatalyst has excellent stability.After 10000 cycles of cyclic voltammetric curve test,the current density did not decrease significantly.Theoretical calculations disclose that the flexible modulation of electronic structures of RuPd ultrathin NSs is achieved by utilizing the additional 3d transition metals Fe,Co,and Ni.In particular,the Ni-3d bands act as the continuous electron-supply center for Ru to ensure an efficient electron transfer toward the adsorbates.Meanwhile,the stable Pd sites are critical for coupling the O-2p?orbital in the initial H₂O splitting with a facile barrier.?2?The nitrogen fixation reaction has an irreplaceable impetus for human life and world progress,but industrial ammonia production has a large energy input and is likely to cause environmental pollution,so electrocatalytic NRR appears to be exceptionally environmentally friendly.Achieving efficient ammonia production at low overpotentials has always been the goal pursued by scientists.This chapter,using oleylamine as a solvent and molybdenum carbonyl as a reducing agent,a high-entropy alloy?HEA?nanomaterial was synthesized by a simple solvothermal method which called Ru FeCo NiCu high-entropy alloy nanoparticles and apply them to NRR.According to the experiments,there is a high NH₃ yield at a low overpotential.When the test potential is 0.1 V vs.RHE in 0.1 M KOH,it has a surprising NH₃ yield of 58.57?g h^-1 mg^-1_cat(29.28?g h^-1 cm^-2),and the corresponding Faradaic efficiency?FE?reaches 26.4%,which is the electrocatalyst with the highest NH₃ yield at the voltage of 0.1 V vs.RHE reported so far.Similarly,the material also exhibits excellent electrochemical properties in other electrolytes such as 0.1 M Li₂SO₄,0.1 M Na₂SO₄ and 0.1 M HCl electrolytes.Besides,it also has an excellent electrochemical stability.After the 100 h test,only slightly diminished in activity.Density functional theory?DFT?shows that Fe surrounded by alloy metals is the best site for N₂ adsorption and activation.Co-Cu and Ni-Ru couples show an excellent capacity to surface hydrogenation at a low overpotential,in which case*H preferentially adsorbs on these sites.*H makes it easier to activate the adsorbed N₂ which from adjacent Fe with maximum energy input?0.32 eV?,and finally reduced to NH₃.