Activity-Stability Trends of the Sb-SnO₂@RuO Heterostructure toward Acidic Water Oxidation

Accomplishments of enhanced activity and durability are a major concern in the design of catalysts for acidic water oxidation. To date, most studied supported metal catalysts undergo fast degradation in strongly acidic and oxidative environments due to improper controlling of the interface stability caused by their lattice mismatches. Here, we evaluate the activity-stability trends of in situ crystallized antimony-doped tin oxide (Sb-SnO₂)@RuO (Sb-SnO₂@RuO) heterostructure nanosheets (NSs) for acidic water oxidation. The catalyst prepared by atomic layer deposition of a conformal Ru film on antimony-doped tin sulfide (Sb-SnS₂) NSs followed by heat treatment highlights comparable activity but longer stability than that of the ex situ catalyst (where Ru was deposited on Sb-SnO₂ followed by heating). Air calcination for in situ crystallization allows the formation of hierarchical mesoporous Sb-SnO₂ NSs from as-prepared Sb-SnS₂ NSs and parallel in situ transformation from Ru to RuO, resulting in a compact heterostructure. The significance of this approach significantly resists corrosive dissolution, which is justified by the enhanced oxygen evolution reaction (OER) stability of the catalyst compared to most of the state-of-the-art ruthenium-based catalysts including Carbon@RuO (which shows ∼10 times higher dissolution) as well as Sb-SnO₂@Com. RuO and Com. RuO₂. This study demonstrates the controlled interface stability of heterostructure catalysts toward enhancing OER activity and stability.