Flash joule heating synthesis of carbon supported ultrafine metallic heterostructures for high-performance overall water splitting

Hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are pivotal electrochemical reactions in water splitting and require efficient and durable electrocatalysts. Developing carbon-supported ultrafine nanocrystals embracing rich active sites serves an effective strategy to produce efficient electrocatalysts. Herein, we report a facile flash joule heating technology to prepare bifunctional electrocatalyst toward HER and OER, in which ultrafine Cu and Ru metallic heterostructures confined within carbon matrix are directly coated on the conductive carbon cloth (Ru-Cu@CM/CC). Benefiting from the homogeneously dispersed nanoclusters with rich active sites, Ru-Cu@CM/CC shows remarkable performance for HER and OER in both alkaline and acid solution, outperforming Pt/C and RuO2, respectively. Remarkably, the two-electrode electrolyzers using Ru-Cu@CM/CC display low voltages in alkaline and acid electrolyte. The exemplified Ru-Cu@CM/CC illustrates the effectiveness of flash joule heating strategy in preparing metallic heterostructures. The satisfactory electrocatalytic performance also inspires the construction of heterostructures for overall water splitting.