Systematic Study of Oxygen Evolution Reaction Activity and Stability of Sn n Sb m Nb l O x Ternary Oxide-Supported IrO2 Catalysts

SupportingIrO(2) with conductive oxides has proven tobe a practical way to increase the conductivity of the catalyst layeras well as decrease the anode IrO2 loading in proton exchangemembrane electrolyzers. In this work, we proposed a high-throughputaerogel synthesis method to fabricate Sn-Sb-Nb ternaryoxide supports. Their thermal stability, conductivity, and acidicstability were then systematically investigated; the results showthat Nb addition decreases the ternary oxide's conductivityby eliminating charge carriers. At the same time, Nb doping improvesthe thermal stability and increases the specific surface area of theternary oxides; acidic stability is also increased with 5 at % Nbaddition. IrO2 nanoparticles are deposited on selectedoxide aerogels via the Adams fusion method to synthesize 50 wt % IrO2/Sn n Sb m Nb l O x catalysts.The catalytic performance and stability of catalysts with varioussupports were compared, revealing a boosted intrinsic activity thanunsupported IrO2. The optimal ternary oxide support employedin this work was Sn80Sb15Nb5O x . Its supported catalyst counterpart hasa mass activity of 467 A g(-1) at 1.6 V (vs reversiblehydrogen electrode) and a Tafel slope of 43.43 +/- 0.43 mv dec(-1). Compared with other Nb doping amounts, 5 at % Nbcatalyst dissolves Ir the least during the oxygen evolution reactiontest, which we ascribed to Nb sacrifice. Moreover, the surface areaof the supporting materials shows more remarkable influence on theresistance of the catalyst layer than their conductivity, which mattersonly when the supported catalysts have an approximate surface area.This finding also puts forward a strategy for the screening of supportingmaterials and provides valuable data for the design and predictionof supporting materials.