Carbon nanofiber-supported tantalum oxides as durable catalyst for the oxygen evolution reaction in alkaline media

Sulfur-Doped Carbon Nanofibers as Support for Tantalum Oxides Bifunctional Catalysts for the Oxygen Reduction and Evolution Reactions

“…This is more evident in peaks (0 0 1) and (0 0 2) of Ta 2 O 5 , which appear about 0.2-0.3 • shifted to higher Bragg angles (2θ) compared to the ICDD reference (JCPDS#89-2843). The contraction of the unit cell, together with chemical composition discussed before, could be associated to oxygen deficiency, as stated in previous works [33,34,41].…”

“…The content of sulfur decreases slightly after introducing the tantalum-based catalytic particles (Table 1), most probably because of the increase of the relative content of tantalum species, which is consistent with the decrease of carbon concentration. With regard to the metallic phase, ICP analysis showed less content of Ta for S-doped CNF catalysts than for the undoped one following the same synthesis procedure (Table 2) [34]. The porous structure of supports was evaluated by nitrogen physisorption.…”

“…Tantalum-based oxides (general formula TaO x ) were deposited on the sulfur doped CNF by a microemulsion procedure [34]. The microemulsion (ME) consisted of mixing 0.25 mL of 75 mM NaOH aqueous solution (Alfa Aesar, 99.99%) with an oil phase composed of 2.3 g of surfactant (Igepal CO-520, Aldrich), 20 mL of n-heptane (Honeywell) and 0.75 mL of ethanol (Labkem, 99.5%).…”

“…In previous works, we investigated a microemulsion procedure to create tantalum based catalysts [33], and carbon nanofibers as support for such tantalum-based nanoparticles, which demonstrated to be active and durable for OER [34]. Oxides from metals of groups 4 and 5 of the periodic table are known as highly durable catalysts, which combined with CNFs, represent a good opportunity towards durable and active bifunctional oxygen catalysts.…”

Growth, Properties, and Applications of Branched Carbon Nanostructures

“…CNSs have been widely studied in electrocatalysis, usually in combination with other components, such as metals [55][56][57][58][59][60][61][62][63][64] and oxides [65][66][67][68][69][70][71][72] or both [73][74][75][76][77], to attain enhanced performance [78], but also in metal-free electrocatalysis [79] for more sustainable solutions [80]. Branched CNSs are promising materials to use with various electrocatalysts for cathodic oxygen reduction reaction (ORR) [81][82][83][84][85][86], oxygen evolution reaction (OER) [81,84,87,88], and hydrogen evolution reaction (HER) [89][90][91][92].…”