| With increasing attention to the energy crisis of traditional fossil fuels and global climate change caused by carbon emissions,people have been committed to the development of clean,environmentally friendly and sustainable energy.Hydrogen(H2)has the advantages of high energy density(146 kJ g-1),abundant reserves,sustainability and zero emission of carbon dioxide(CO2).It is recognized as the most promising clean energy alternative to fossil fuels in the future.Because hydrogen evolution reaction(HER)has the advantages of large-scale production of high-purity hydrogen,low carbon emissions,and sustainability,it has attracted more and more attention in the research and industrial fields.The precious metal platinum(Pt),which has the best inherent catalytic activity for HER,is regarded as the benchmark electrocatalyst in water electrolysis.Due to the low reserves,poor stability,and high price of Pt-based metals,their large-scale application is limited.Ruthenium(Ru)is a relatively cheap precious metal,and its cost is only 25%of Pt.Although pure Ru exhibits moderate intrinsic activity to HER due to its strong binding force to hydrogen,the coupling of Ru to nanocarbon can be comparable to the activity of Pt-based HER.Therefore,it is attractive to explore a highly efficient Ru-based catalyst with excellent stability as a substitute for Pt.Based on this,this article uses boron-containing small molecules as precursors to prepare boron-doped carbon dots(B-CDs),and RuCl3·xH2O is subjected to secondary hydrothermal,pyrolysis and other processes to prepare B-CDs supported Ru nanocrystals(Ru@B-CDs)composite catalysts.We apply this catalyst to HER,which has excellent catalytic performance.Under 1.0 M KOH solution,the catalyst has an overpotential of 14 mV at a current density of 10 mA cm-2.After 2000 CV cycles,the overpotential increased by only 6 mV.Compared with other Ru-based metal catalysts,it has superior catalytic performance.In order to further reduce the cost,biomass was used as a carbon source to prepare CDs.While reducing the Ru content(2.18%),Fe was introduced,which greatly reduced the cost of the catalyst.At the same time,the synergistic effect of Ru and Fe improved the catalytic activity of the catalyst.Under 1.0 M KOH solution,the catalyst has an overpotential of 17 mV at a current density of 10 mA cm-2.After 2000 cycles of CV,there is almost no change in the overpotential.Based on the previous work,we considered changing the morphology of the catalyst to explore its impact on the catalytic performance.Therefore,we selected silica as the template and prepared hollow carbon spheres with RuFe metal particles supported by the one-step pyrolysis method(RuFe@HPCS)composite materials.The hollow structure can provide a large specific surface area and more active sites,so the catalyst has catalytic performance close to commercial Pt/C even when the Ru content(1.23%～1.78%)is very low. |
