In-situ synthesis of NiCoN/N-doped carbon ultrathin nanosheet arrays by supramolecular pyrolysis for boosting electrocatalytic hydrogen evolution in universal pH range water and natural seawater.

Nanostructured electrocatalysts with unique surfaces and interfaces for hydrogen evolution reaction (HER) are crucial for achieving high performance in universal pH water and natural seawater. Herein, a supramolecular liquid precursor was designed and applied to grow NiCoN/N-doped carbon (NC) ultrathin nanosheet arrays (NiCoN/NC) on carbon cloth through one-step pyrolysis. According to the X-ray absorption spectra, Ni was successfully alloyed into CoN to form NiCoN/NC, which regulates the intrinsic electronic structure and optimizes the adsorption/desorption energy of the catalyst. The unique structure of NiCoN anchored on NC can increase the electron transport efficiency and protect the catalyst from corrosion in the extreme corrosive electrolytes. As a result, the NiCoN/NC catalyst exhibits excellent electrocatalytic HER activity over a wide pH range requiring only 46, 75, and 55 mV at 10 mA/cm in the acidic, neutral, and alkaline electrolytes, respectively. Interestingly, the catalyst also shows outstanding HER performance in the natural seawater. This work provides an alternative option for the rational design of efficient electrocatalysts for universal pH water/seawater splitting.