Study On The Electrocatalytic Performance Of Functionalized MXene Supported Ru Based Catalyst

Electrolysis of water to produce hydrogen converts water molecules into hydrogen and oxygen,which is one of the main means to obtain pure hydrogen energy.Electrolytic water reaction mainly includes two half reactions,hydrogen precipitation(HER)and oxygen precipitation(OER),which include multi-step proton coupling and electron transfer reactions.This process requires a large potential to drive the occurrence of water decomposition reaction,seriously reducing the energy conversion efficiency of the entire hydrogen production device.Excellent electrolytic water catalysts can effectively reduce the large potential required for the reaction and reduce energy consumption.However,the application of traditional commercial Pt/C catalysts is restricted due to the high price of precious metal Pt and the scarcity of Pt metal resources.The catalytic performance of non noble metal catalysts cannot be compared with that of noble metals,and problems such as poor cycle stability cannot be well resolved.Therefore,this thesis aims to use the relatively inexpensive precious metal Ru to replace the precious metal Pt as the reactive active material,and regulate the morphology of Ru-based catalysts,the size of Ru metal nanoparticles,and the electronic structure of the surface of active sites by using conductive carriers such as Ti3C2Tx MXene,metal alloying,and dual carrier recombination.Preparation of Ru-based catalysts with excellent performance and stability while effectively reducing costs.The main research content of this paper includes the following parts:(1)Designing and preparing high-efficiency HER electrocatalysts is particularly important for improving the hydrogen production rate and saving the cost of hydrogen production.Firstly,this chapter uses ozone functionalization,solvothermal method,and vacuum freeze drying processes to prepare 3D structures Ru-OCNT/Ti3C2Tx catalyst.By adjusting the ratio of functionalized carbon nanotubes(OCNT)to Ti3C2Tx,a uniform surface distribution of carbon nanotubes was ultimately prepared OCNT/Ti3C2Tx The composite carrier avoids the stacking of Ti3C2Tx sheets and the aggregation of OCNT,exposes rich active sites and constructs multiple ion electron transfer channels.At the same time,by forming an OCNT conductive bridge,Ti3C2Tx and OCNT can be effectively chemically compounded,greatly improving the stability of Ti3C2Tx nanosheets.In electrochemical testing,whether under acidic or alkaline conditions,Ru-OCNT/Ti3C2Tx Compared with Ru-OCNT and RuTi3C2Tx supported on a single carrier,the catalyst has advantages of high HER catalytic activity,good cycle stability,and fast kinetics.Under acidic conditions,Ru-OCNT/Ti3C2Tx With only 42 mV,a current density of 10 mA cm-2 can be achieved,which is superior to RuOCNT,Ru-Ti3C2Tx,and commercial Ru/C catalysts.Under alkaline conditions,RuOCNT/Ti3C2Tx still exhibits excellent electrocatalytic activity,with superior overpotential and Tafel slope compared to Ru-OCNT,Ru-Ti3C2Tx,and commercial Ru/C catalysts.This work provides an idea for the preparation of highly functional MXene supported Ru based catalysts for the study.(2)Developing bifunctional total hydrolysis catalysts with practical application value is still a challenging and indispensable topic.In this work,we successfully constructed RuCo bimetallic alloy nanoclusters on a two-dimensional Ti3C2Tx carrier(RuCo-Ti3C2Tx)through a freeze drying process and a simple high-temperature reduction method.Due to the synergistic effect of RuCo alloy nanoclusters,the high electronic conductivity of MXene,and the Ru-OTi chain,the RuCo-Ti3C2Tx formed exhibits excellent electrocatalytic activity for hydrogen evolution in 0.5 M H2SO4 and 1 M KOH,with an overpotential of 60 mV and 52 mV,respectively,achieving a current density of 10 mA cm-2.In addition,RuCo-Ti3C2Tx has a overpotential of 266 mV at 10 mA cm-2,and has good oxygen evolution reaction(OER)performance.In 1M KOH,a total hydrolysis device using RuCo-Ti3C2Tx as the anode and cathode catalyst can drive a current density of 10 mA cm-2 with a voltage of only 1.56 V,which is lower than the voltage required for a total hydrolysis device composed of traditional Pt/C‖RuO2 electrodes.Density functional theory(DFT)calculations indicate that the excellent synergistic effect between Ru-Co bimetals and the strong anchoring effect of Ti3C2Tx supports on RuCo nanoclusters contribute to improving catalytic performance and stability,as well as enhancing the catalytic active sites.This study provides a feasible and efficient strategy for developing Ti3C2Tx MXene based alloy total hydrolysis catalysts.(3)In the work of this chapter,we successfully prepared the RuCo-OCNT/Ti3C2Tx compound material.By adjusting the mass ratio of Ti3C2Tx to OCNT,the surface of Ti3C2Tx is uniformly coated with OCNT without significant agglomeration of OCNT.By adjusting the ratio of Ru atoms to Co atoms,a RuCo alloy is obtained to avoid excess of a single metal.The OCNT conductive bridge constructs a connection bridge between Ti3C2Tx sheets to avoid stacking of Ti3C2Tx sheets.The OCNT covered on the surface of Ti3C2Tx slices can effectively enhance the electrochemical stability of Ti3C2Tx nanosheets.Compared to the lack of catalytic performance of a single Ru metal in OER,bimetallic RuCo alloys can exhibit excellent catalytic performance in both HER and OER.Benefiting from 1)the synergistic effect of RuCo alloy nanoclusters,2)The OCNT/Ti3C2Tx composite carrier has high electronic conductivity,excellent stability,and high electrochemical active area.In 1 M KOH,RuCo-OCNT/Ti3C2Tx both exhibit excellent electrocatalytic activity for hydrogen evolution(HER)and excellent electrocatalytic activity for oxygen evolution(OER),with an overpotential of 25 mV and 244 mV,respectively,achieving a current density of 10 mA cm-2.In 1M KOH.a total hydrolysis device using RuCo-Ti3C2Tx as the anode and cathode catalyst can drive a current density of 10 mA cm-2 with only 1.54 V of voltage,which is lower than the voltage required for a total hydrolysis device composed of traditional Pt/C‖RuO2 electrodes.This study provides a feasible and efficient strategy for developing Ti3C2Tx MXene based alloy total hydrolysis catalysts.