Effect of B-Doping and Manifestation on TiO₂-Supported IrO₂ for Oxygen Evolution Reaction in Water Electrolysis

To commercialize hydrogen production by proton exchange membrane (PEM) electrolysis, the amount of rare and precious metal (iridium) required for anodic oxygen evolution reaction (OER) must be greatly reduced. In order to solve the problem, carrier loading is used to reduce the amount of iridium. Unlike the carrier modified by conventional metal element doping, this work doped the carrier with the nonmetallic element and then prepared IrO₂/TiBO₂ composite catalyst using the Adams melting method. B-doped TiO₂ supports with different doping amounts show the main phase rutile structure. Among them, the conductivity of B-doped carrier shows an increasing trend with the increase of doping amount, because boron can form holes and negative centers after doping, and more carriers improve the conductivity of the support. In addition, since element B is manifested from inside to outside on the support, B can affect the catalytic process. After the manifestation of element B, the carrier loaded with IrO₂ exhibited superior electrocatalytic properties. The voltammetric charge per unit mass of 40IrO₂/TiB_0.3O₂#2 (where #2 represents B after manifestation) reaches 1970 mC (cm² mg)^-1, the corresponding overpotential is 273 mV at a current density of 10 mA/cm^-2, and the Tafel slope is 61.9 mV/dec Also, the charge transfer resistance is only 15 Ω. Finally, in the stability test, the composite catalyst is also better than pure IrO₂ in the 20 000 s operation. Therefore, element B has an unexpectedly positive effect on the catalytic progress on the surface of the support after its manifestation.