Loading uniformly distributed CuRu alloys on carbon nanotubes via flash Joule heating for high-performance electrocatalytic water splitting

Constructing highly efficient and stable electrocatalysts is the key to reducing the overall energy input for electrocatalytic water splitting, which ensures the reduced cost of environmentally friendly hydrogen resources with high energy density. Assisted by ultrafast pyrolysis with a flash Joule heating technique, CuRu ultrasmall alloy nanoparticles are uniformly coated on carbon nanotubes (CNTs) with tannic acid (TA) to chelate metal ions. During the pyrolysis procedure, the self-assembled TA molecules not only offer a cross-linked porous polyphenol framework but also provide more interactions to link the alloy nanoparticles and CNT substrates, forming highly conductive electrocatalysts with uniformly dispersed ultrasmall alloy metallic nanoparticles (∼ 4.3 nm in diameter) on the surface of porous CNTs (CuRu-CNTs). In particular, CuRu-CNTs with Cu-Ru alloy nanoparticles achieve the highest electrochemical activity, exhibiting tiny HER and OER overpotential of 39 mV and 330 mV at 10 mA cm−2 in 1.0 M KOH medium. The unique bifunctional feature of CuRu-CNTs allows good overall water splitting activity (10 mA cm−2 for 12 h), which is comparable with the best noble metal-based benchmark. This contribution provides a general energy saving pyrolysis method for the preparation of highly efficient, cost-effective and chemically stable electrocatalysts for water splitting.