Electrocatalytic Properties Of Interfacial Functionalized Rhodium-based Nanocrystals

The massive burning of fossil fuels has caused serious environmental pollution,and it is urgent to develop clean energy to replace traditional fossil energy.Hydrogen with high energy density and zero carbon emissions is widely regarded as the most promising candidate for achieving a carbon neutral world and sustainable energy future.In the long run,the hydrogen economic structure will replace the fossil energy system and achieve the goal of global environmental protection and sustainable development.Among various hydrogen production technologies,electrochemical water splitting technology is regarded as an attractive,promising and reliable future energy technology due to its high efficiency and convenience.Nevertheless,electrochemical water splitting technology still requires an efficient electrocatalyst to enhance the slow kinetic rates of hydrogen evolution and oxygen evolution reactions.In this paper,a series of rhodium(Rh)-based nanomaterials were synthesized through the strategies of interfacial vacancy engineering,metal-functional molecule composite interface engineering,and interfacial doping engineering,which were applied in the study of hydrogen production by electrolysis of water.The main research contents are as follows:(1)This chapter improves the electrocatalytic performance of noble metals and the atomic utilization of metals by using interfacial vacancy engineering strategies.Using bowl-shaped carbon materials as substrates not only provides a stable substrate for anchoring metal atoms,but also the strong interaction.Between the metal and the substrate can improve the catalytic activity of the catalyst,and the carbon atoms adjacent to the metal also form a stable substrate.The additional active sites further enhance the overall catalytic activity.In this chapter,the vacancy-rich bowl-shaped carbon material is coupled with Rh nanoparticles(Rh@HCNs),which greatly reduces the amount of noble metal while ensuring the catalytic efficiency.Specifically,Rh nanoparticles are trapped by these carbon vacancies and anchored purposefully in vacancy-rich carbon bowls,which preventing the aggregation of Rh nanoparticles and ensuring high dispersion of the particles.Under harsh conditions of strong bases and strong acids,Rh@HCNs only requires overpotentials of 42 m V and 38 m V to reach a current density of 10 m A cm^-2.(2)In this chapter,the interface engineering of noble metals and functional molecules can improve the specific surface area,electrical conductivity,diffusion coefficient and metal atom utilization rate of the material,improving the intrinsic activity of the catalytic material and further improving the performance of the material.In this chapter,a spiny spherical-like porous Rh nanostructure functionalized with polyethyleneimine was synthesized by a solvothermal method,which was formed by the self-assembly by two-dimensional Rh subnanosheets.As a good electron donor,?NH₂on polyethyleneimine can adjust the electronic structure of Echinops-like Rh PNNSs to reduce the adsorption energy of surface water molecules and increase the adsorption energy of OH^-.Meanwhile,the?NH₂ groups on polyethyleneimine can specifically enrich water molecules under neutral conditions,and promoting water adsorption.The synthesized Echinops-like Rh PNNSs have the characteristics of outstanding hydrogen evolution activity,low overpotential,low Tafel slope and excellent stability.In neutral media,Echinops-like Rh PNNSs required to achieve a current density of 10 m A cm^-2.only need an overpotential of 79.5 m V.When Echinops-like Rh PNNSs were used as anode and cathode catalysts for seawater splitting,respectively,only a cell voltage of1.61 V was needed to achieve a current density of 10 m A cm^-2,which greatly improved the efficiency of seawater splitting.(3)In this chapter,the catalytic activity of the catalyst is improved by maximizing the activation of the number of active sites of the catalyst by using the interfacial doping strategy of inorganic metal atoms.Electrocatalytic ethylene glycol oxidation reaction can replace the slow thermodynamic oxygen evolution reaction due to its lower reaction thermodynamics,and can produce high value-added chemical products while achieving energy saving and hydrogen evolution.In this chapter,we designed and synthesized Rh atom-decorated Pt Rh nanowires(Pt Rh0.02@Rh nanowires)by a simple one-step solvothermal reduction method by controlling the reduction rate of metal precursors,which exhibited excellent performance in hydrogen evolution reaction and ethylene glycol oxidation.All of them showed excellent catalytic performance.The interfacial strain effect produced by metal co-doping effectively modulates the electronic structures of Pt and Rh,which helps to introduce heteroatomic active centers and induce lattice strain,thereby achieving excellent electrocatalytic performance.Pt Rh0.02@Rh nanowires exhibited excellent HER performance in both alkaline freshwater and alkaline seawater.Low overpotentials of 30.6 m V and 45.8 m V,Tafel slopes of 39.1 m V dec^-1and 39.5 m V dec^-1,respectively,at a current density of 10 m A cm^-2.Meanwhile,the Pt Rh0.02@Rh nanowires also exhibit excellent stability due to the special one-dimensional structure and alloy properties.Meanwhile,the Pt Rh0.02@Rh nanowires also exhibit excellent stability due to the special one-dimensional structure and alloy properties.When Pt Rh0.02@Rh nanowires are used as the catalytic material of cathode HER and anode EGOR,respectively,the cell voltage of Pt Rh0.02@Rh nanowires(HER)?Pt Rh0.02@Rh nanowires(EGOR)only needs to be A current density of 5 m A cm^-2 can be achieved at 0.69 V,which is much smaller than the voltage of Pt Rh0.02@Rh nanowires(HER)?Pt Rh0.02@Rh nanowire(OER).Meanwhile,electrochemical in situ Fourier transform infrared spectroscopy results indicated that the as-synthesized Pt Rh0.02@Rh nanowires promoted the oxidation of EG and transformed ethylene glycol into high-value glycolic acid.It is confirmed that Rh atoms modified on the surface of Pt nanowires can provide effective strain effects to optimize active sites,opening up a new strategy for designing efficient and durable bifunctional catalysts.