In-situ synthesis of NixCo4-xN/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 NixCo4-xN/N-doped carbon (NC) ultrathin nanosheet arrays (NixCo4-xN/NC) on carbon cloth through one-step pyrolysis. According to the X-ray absorption spectra, Ni was successfully alloyed into Co4N to form NixCo4-xN/NC, which regulates the intrinsic electronic structure and optimizes the adsorption/desorption energy of the catalyst. The unique structure of NixCo4-xN anchored on NC can increase the electron transport efficiency and protect the catalyst from corrosion in the extreme corrosive electrolytes. As a result, the NixCo4-xN/NC catalyst exhibits excellent electrocatalytic HER activity over a wide pH range requiring only 46, 75, and 55 mV at 10 mA/cm2 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.