Dual Modification of Stainless Steel by Small Molecule Oxalic Acid for Oxygen Evolution Reaction

A electrocatalyst with low cost and high performance is the key to achieve the industrial application of hydrogen energy. In this work, inexpensive commercial stainless steel is modified by a simple hydrothermal method. For the first time, surface corrosion modification and active substance loading are realized simultaneously with small-molecule oxalic acid. Compared with 304-type stainless steel mesh (SSM-304), the overpotential of the sample after two-step treatment (noted as OESSM) is largely decreased (125 mV), and exceptional stability (48 h) is achieved. In acidic hydrothermal corrosion, the metal on the surface of stainless steel is eroded into the solution. Then, the C2O42– recomplexes with the dissolved metal ions, and the oxalate is grown on the surface. The excellent catalytic activity and stability come from the unique framework structure of the metal oxalate crystals. Oxalic acid is widely available and with double carboxyl group in C2O42–. The electrons enriched in CO can enhance the adsorption energy on the catalyst surface and induce the production of active catalytic sites *OOH. In addition, the oxalate crystal framework provides critical support for maintaining positive catalytic activity and stability. This work creates the possibility of realizing the large-scale application of stainless steel-based electrocatalysts in actual production