Research On Improving The Electrocatalytic Performance Of Precious Metal Electrode Surface Interface Regulation In Eutectic Solvent

Catalysis is the process of modifying a chemical reaction with the use of a catalyst.This process only works with chemicals that have an existing reaction,and used to accelerate the reaction for commercial purposes.Metal-support interaction playing a key role for the catalytic performance of supported metal catalyst,it can regulate the electronic structure and chemical properties of the active phase by affecting the bonding and charge transfer between the carrier and the loaded metal particles.In this paper,strong metal-supported interacting metal particles（Pd and Ag）were synthesized on the surfaces of nickel and copper substrates using special physicochemical properties of deep eutectic solvents（different from aqueous solution）by simple displacement reactions（combined with electrochemical redox）.The catalytic performance of them as fuel cell electrodes was investigated.The specific work is as follows:（1）Well-defined Pd nanoparticles（Pd NPs）developed on Ni substrate（Pd NPs/Ni）were synthesized via a facile galvanic replacement reaction（GRR）route performed in ethaline-based deep eutectic solvent（DES）.For comparison,a Pd NPs/Ni composite was also prepared by the GRR method conducted in an aqueous solution.The Pd NPs/Ni obtained from the Ethaline-DES was catalytically more active and durable for the methanol electro-oxidation reaction（MOR）than those of the counterpart derived from conventional aqueous solution and commercial Pd/C under alkaline media.Detailed kinetic analysis indicated that the unique solvent environment offered by ethaline played vital roles in adjusting the reactivity of the active species and their mass transport to control the generation of the Pd NPs/Ni nanocomposite.The resulting Pd NPs/Ni catalyst possessed a homogeneous dispersion of Pd NPs with a strong Pd（metal）-Ni（support）interaction.This structure enhanced the charge transfer between the support and the active phases,and optimized the adsorption energy of OH^-and CO on the surface,leading to superior electrocatalytic performance.This work provides a novel GRR strategy performed in Ethaline-DES to the rational design and construction of advanced metal/support catalysts with strong interaction for improving the activity and durability for MOR.（2）Silver nanoparticles（Ag NPs）developed on a Cu substrate,Ag NPs/Cu,were synthesized by a novel and facile GRR route performed in Ethaline DES.It revealed that the Ag NPs could be well dispersed on the Cu support and delivered significantly enhanced activity and stability for the oxygen reduction reaction（ORR）in alkaline media via an in-situ electrochemical oxidation-reduction（ECO-ECR）activation process.The in-situ redox tuning triggered a reversible phase transformation of the formed initially Ag NPs,Ag?Ag₂O,with restructuring at the surface and given rise to a strong metal-support interaction with tailored atomic/electronic structures,which are responsible for the enhanced ORR activity.GRR kinetics between Cu substrate and Ag^I ions in Ethaline revealed that Ni^II ions can regulate by mitigating the diffusion of Ag^I ions and the subsequent growth of Ag on the surface,leading to the formation of uniformly distributed Ag NPs.The optimal Ag-Ni₁ NPs/Cu＿ECO-ECR exhibited ORR activity similar to that of commercial state-of-the-art Pt/C with the same mass loading,and better long-term durability（95%activity retention after30000 s）,cyclic stability performance,and anti-poisoning capacity for methanol（96%activity retention after 3300 s）,showing as a promising efficient ORR electrocatalyst for practical application.