WO₃ Nanosheet-Supported IrW Alloy for High-Performance Acidic Overall Water Splitting with Low Ir Loading

Abstract

Precious metals (like Ir, Ru, and Pt) and their derivatives are the benchmark catalysts for water splitting in acidic media due to their high stability and activity. However, the high cost and scarcity of these materials hamper the large-scale applications. To solve this issue, construction of catalysts containing low content of precious metals with high intrinsic activity can be an efficient strategy, which expectedly can decrease the cost but meanwhile preserve the activity. Herein, we synthesized an IrW/WO3 array catalyst by in situ formation of IrW alloy on hierarchical WO3 nanosheet arrays. With extremely low Ir content of 1.25 wt % in 0.5 M H2SO4, this composite catalyst not only shows superior water oxidation activity (the overpotential at 10 mA cm–2 is only 229 mV, significantly lower than that of the commercial IrO2 (358 mV)) but also exhibits excellent proton reduction performance (the overpotential at −10 mA cm–2 is 49 mV, close to that of commercial Pt/C catalyst (42 mV)), showing promising bifunctionality for the overall water splitting. As a result, only 1.5 V is needed to drive the overall water splitting at 10 mA cm–2 with a good long-term stability under acidic conditions. These remarkable features can be ascribed to the abundant active sites exposed by the three-dimensional nanostructure, and the high intrinsic activity per Ir site. The theoretical calculation verifies that Ir sites in IrW surface after oxidation have a higher intrinsic activity than IrO2 for water oxidation. We believe this research can supply a strategy to design highly active and stable catalysts with low loading of noble metals for acidic water splitting.

Development of IrO2–WO3 Composite Catalysts from Waste WC–Co Wire Drawing Die for PEM Water Electrolyzers’ Oxygen Evolution Reactions

“…When the current densities are examined, it is seen that the IW-75 catalyst has a relatively better result among the catalysts in the literature by 30 mA cm –2 . On the other hand, the IrW/WO 3 -NS-A catalyst study by Zhou et al provides higher active sites by their three-dimensional nanostructures, and they obtained 44.830 mA cm –2 current density values. Here, the developed catalysts in this study have very close result with a three-dimensional synthesized catalyst with less synthesis step.…”

Perspectives on the development of highly active, stable, and cost‐effective OER electrocatalysts in acid

“…Introducing low‐cost materials is one of the most intuitive and efficient ways to reduce the cost of noble metal‐based catalysts 156–162 . Some cases have been reported in which precious metals such as Ir and Ru are significantly reduced through the alloying processes to increase economic feasibility and exhibit excellent catalytic performance.…”

Ni nanoparticles assembled on the surface of biomass-derived porous carbon as competitive candidates for the hydrogen evolution reaction

“…Nevertheless, the scarcity and considerable cost have greatly restricted their widespread application. 12 Therefore, it is imperative to exploit electrocatalysts with remarkable electrocatalytic activity, low cost, and environmental friendliness. 13,14…”

“…Nevertheless, the scarcity and considerable cost have greatly restricted their widespread application. 12 Therefore, it is imperative to exploit electrocatalysts with remarkable electrocatalytic activity, low cost, and environmental friendliness. 13,14 A range of nickel-based catalysts has been widely investigated over the past decades, including oxides, 15,16 hydroxy oxides, 17,18 sulfides, 19,20 nitrides, 21,22 and phosphates,.…”