Electrocatalytic Property Of Noble Metals And Iron-containing Compounds Toward Water Splitting

Hydrogen production from electrolyzed water is an effective way to convert and store unstable wind energy,water energy and solar energy,which has broad prospects for addressing the full use of renewable energy.However,the energy conversion efficiency of hydrogen production from electrolyzed water is still too low to meet actual demand.It is believed that the slower anodic oxygen evolution reaction?OER?,compared with the rapid cathodic hydrogen evolution reaction?HER?,is the main factor constraining the energy conversion efficiency of electrolyzed water whole reaction.Therefore,it is essential to design and develop an efficient anodic oxygen evolution catalyst.Base on the above,this paper focuses on the synthesis of catalysts based on noble metals and iron-containing compounds and their catalytic activity for anodic oxygen evolution in electrolyzed water.The main conclusions are as follows:?1?The present work reports a general approach to improve the electrocatalytic property of noble metal through regulating its electron status by employing the strong metal-support interaction?SMSI?.As a case study,the catalytic activity of metallic Pd towards oxygen evolution reaction?OER?in alkaline solution has been significantly promoted by stabilizing Pd^?+oxidic species at Pd-metal oxide interface with the help of SMSI electronic effect,suggesting an intrinsic advantage of Pd^?+in driving OER.And we further demonstrate that the chemical state of Pd^?+can be easily modulated in the range of+2 to+3 as changing the metal oxide attached,interestingly,accompanied by a clear dependence of the OER activity on the oxidation state of Pd^?+.The higher Pd³⁺species-containing Fe₂O₃/Pd catalyst has an impressively enhanced OER property,showing an overpotential of 383 mV at 10 mA·cm^-2 compared with those of>600 mV on metallic Pd and 540 mV on Fe₂O₃/glass carbon.?2?An efficient bifunctional iron-doped nickel phosphide electrocatalyst was prepared for water splitting.The results showed that the catalyst not only exhibited significant OER activity under alkaline conditions but also had excellent HER activity and total electrolyzed water activity.The overpotential of catalyst for OER and HER are300 mV and 211 mV at 100 mA·cm^-2 in 1 M KOH,relatively.the voltage of water splitting is 1.756 V,while the activity occurs no significant attenuation after 15 h durability test.?3?A liquid-phase coprecipitation method was used to structure metal organic framework catalysts about Prussian Blue based on Fe and Co.The study shows that these catalysts have excellent OER activity in 1 M KOH,and the ratio of elemental composition has a significant effect on thoes activity.Especially,The over-potentials of 3Co2FeHCF?HCF:K₃Co?CN?₆?and 2Co3FeHCC?HCC:K₃Co?CN?₆?are 369 mV and 363 mV at 5mA·cm^-2,while the overpotentials of FeHCF,CoHCF,FeHCC,and CoHCC are 416 mV,372 mV,566 mV,and 450 mV,respectively.?4?Prussian blue OER catalysts are modified on the surface of nano?-Fe₂O₃photoanode materials by electrodeposition and impregnation.The catalytic performance of nano?-Fe₂O₃ was studied for the photoelectrocatalytic water-splitting.The experiment,under 100 mW·cm^-2 illumination conditions at 1.23 V?vs RHE?,shows that the photocurrent density of the nano?-Fe₂O₃ catalyst with modified Prussian blue structure promoting catalyst could be increased by 18.2%than before.