Boron-Doped Activated Carbon Supports for Cobalt-Catalyzed Oxygen Evolution in Alkaline Electrolyte

Abstract

Activated carbons (ACs) are the most widely used and attractive support materials for electrocatalytic applications because of their significant surface areas, high electrical conductivities, and moderate affinities toward supported metal catalysts. However, the corrosive behavior of ACs at oxidative potentials causes an inevitable reduction in the active surface area of supported catalysts, resulting in the continuous deterioration of their electrocatalytic performance. Therefore, the introduction of corrosionresistant durable catalyst supports is essential for sustainable and efficient electrocatalysis. Here, we modified ACs to obtain different boron (B)-doped structures via doping-temperature controls to investigate the corrosion resistance of B-doped ACs. With increasing doping temperature, the B-doped ACs exhibited a decreased defect density and enhanced crystallinity owing to the accelerating dopant-induced graphitization. We found that the substitution of B atoms into the carbon lattice improved the structural integrity of the carbon structure, and cyclic voltammetry (CV) tests suggested that the highly B-substituted structures caused electrochemical surface passivation against carbon corrosion. Moreover, B-doped ACs significantly contributed to the increase in loading mass of cobalt (Co)-based catalyst on them and the electrochemical durability toward the oxygen evolution reaction as catalyst-support hybrid. The B22 (B-doped AC obtained at a 2200 °C B-doping temperature)-supported Co catalyst with the lowest oxidation current exhibited a voltage change of 32 mV at a current density of 10 mA/cm 2 (ΔE j=10 ) after 10,000 cycles, which was a factor of ∼7 higher cycle durability and stability than that of the conventional IrO 2 catalyst (ΔE j=10 = 205 mV). Here, we propose that surface engineering by B-doping to improve the structural integrity of ACs is an attractive method for designing durable electrocatalytic support materials.

Effects of Potassium-Based Activating Agents on the Biochar Derived from Coconut Tree Husk for Enhancing the Surface Area and Supercapacitor Performance

“…Different activating agents affecting the number of defects and the graphitic nature of the sample lead to different I D / I G ratios. The lowest I D / I G ratio carbon material is suitable for electrode application because of its high electrical conductivity. − From the above results, the AC using KMnO 4 activating agent exhibits a low I D / I G ratio, which is favorable for fast electrochemical charge transfer.…”

An ecofriendly and universal strategy to balance the active sites and electrical conductivity of biomass-derived carbon for superior lithium storage

“…This trend suggests that the O doping induced defects and disordered structures were partially repaired by the introduced B. 26 Moreover, the specific surface area and pore size distribution of the BO-CNS was quantitative analyzed using the N 2 adsorption–desorption isotherms shown in Fig. 2d and e.…”

Confinement engineering for enhanced electrocatalytic nitrate reduction by integrating B-doped graphene with iron catalysts for long-term stability

“…2e). 46 Among them, the BC 3 structure indicates the substitution of B atoms for C atoms in the G framework, while the BC 2 O and BCO 2 structures indicate the substitution of B atoms for C atoms at the edges or defective positions of the framework. The above analysis indicates that B atoms are substituted at the edges or defective positions of the G framework, and that the G framework doped with B atoms maintains its original planar conjugated structure.…”