Facile sol-gel preparation of high-entropy multielemental electrocatalysts for efficient oxidation of methanol and urea

High-entropy multi-elemental (HEM) electrocatalysts present superior catalytic performance due to the efficient synergism of their components. HEM electrocatalysts are usually prepared through hydrothermal reactions or calcination, which could generate undesired heterogeneous structures that hinder the exploration of the structure-property relationship of these HEM electrocatalysts. Herein, we report a sol-gel method to synthesize homogeneous HEM electrocatalysts for electro-oxidation of methanol and urea (methanol oxidation reaction (MOR) and urea oxidation reaction (UOR)), through an acid-catalyzed gelation at room temperature. With Ni as the primary component for MOR and UOR, Co can reduce the overpotentials, while Fe can increase the catalytic activities and durability. Borate and phosphate can tune the charge distribution in active sites and speed up the reaction kinetics through fast proton transfer. Thus, the optimal Ni2Fe0.5Co0.5-BP HEM catalyst demonstrates superior catalytic activity together with good durability and great resistance to CO poisoning. In addition, a direct methanol fuel cell with Ni2Fe0.5Co0.5-BP electrode can not only provide power, but also produce formic acid with high yield and high Faraday efficiency. This work presents a simple strategy to prepare high-performance HEM electrocatalysts for fuel cells and production of value-added chemicals.

Automated summary

This study presents a simple strategy to synthesize high-performance HEM electrocatalysts through a sol-gel method. By adjusting the composition and adding substances such as borate and phosphate, catalysts with excellent catalytic activity, durability, and resistance to poisoning can be obtained. Furthermore, the fuel cell using this electrocatalyst can also produce formic acid efficiently.