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We report that the nanocrystalline CoOx glass composed of mixed amorphous parts and crystalline domains shows high-performance for electrochemical hydrogen production because of the synergistic effects among the nanocrystals and amorphous matrix.

Nickel-based non-noble-metal materials have emerged as promising catalysts for electrochemical hydrogen production in view of their attractive intrinsic activities, electrical properties and low cost. Exploring new candidates for further improving the performances of nickel-based catalysts and understanding the structure–activity relationship are still necessary to reduce the overpotential of the hydrogen evolution reaction (HER) thus advancing their application in electrochemical water splitting. Herein, we developed a facile two-step self-templated strategy for fabricating a three-dimensional (3D) nanoporous nickel/vanadium oxide (Ni/V2O3) nanoplate assembly as a new efficient catalyst for alkaline HER. It is found that by controllably annealing the Ni–V–O assembly as a single precursor, Ni and V2O3 components are uniformly integrated in the nanoporous composite, showing a synergistically enhancing effect on the HER. The resulting 3D nanoporous structure not only creates numerous active sites accessible for the HER but also provides a conductive open network towards efficient electron/mass transport. Consequently, the nanoporous Ni/V2O3 nanoplate assembly exhibits excellent catalytic performance for alkaline HER in terms of a low overpotential of 61 mV at 10 mA cm−2 and a small Tafel slope of 79.7 mV dec−1 together with excellent long-term durability. These findings provide new insights into good design and construction of other highly active catalysts for diverse applications.

To promote the oxygen reduction reaction (ORR) on a non-precious-metal catalyst, integrating two-dimensional (2D) nanosheets and one-dimensional (1D) nanotubes in one catalyst is considered as one of the desirable approaches since this hybrid architecture can host more useful active sites and enhance mass/electron transfer. Herein, we demonstrated a sodium chloride-assisted strategy for the in situ synthesis of a three-dimensional (3D) hybrid of carbon nanosheets and nanotubes. The micrometer-scale sodium chloride (NaCl) crystal acted as a recyclable skeleton to adsorb the precursors on its surfaces, which assisted the formation of micrometer-sized graphitic carbon nanosheets with nanometer thickness by the template effect during the pyrolysis, and iron-based nanocrystals with a size of tens of nanometers by helping the distribution of iron sources and preventing their aggregation. The small iron-based nanocrystals favored the growth of long CNTs connected to carbon nanosheets and the outmigration of carbon atoms during the cooling process, which led to the formation of carbon-layer encapsulated metallic iron nanoparticles between the carbon nanosheets or inside the carbon nanotubes. Benefiting from these features, the developed hybrid exhibited a significantly enhanced electrocatalytic activity and durability for the ORR. The results may open up opportunities for exploring cost-effective high-performance electrocatalysts for energy applications.