Deep eutectic solvent assisted facile synthesis of low-dimensional hierarchical porous high-entropy oxides

High-entropy-oxides(HEOs),a new class of solids that contain five or more elemental species,have attracted increasing interests owing to their unique structures and fascinating physicochemical properties.However,it is a huge challenge to construct various nanostructured,especially low-dimensional nanostructured HEOs under the high temperature synthetic conditions.Herein,a facile strategy using glucose-urea deep eutectic solvent(DES)as both a solvent and the carbon source of structure-directed template is proposed for the synthesis of various HEOs with two-dimentional(2D)nanonets and one-dimentional(1D)nanowires,including rock-salt(Co,Cu,Mg,Ni,Zn)O,spinel(Co,Cr,Fe,Mn,Ni)_(3)O_(4),and perovskite La(Co,Cr,Fe,Mn,Ni)O_(3).The as-prepared HEOs possessed five or more uniformly dispersed metal elements,large specific surface areas(more than 25 m^(2)·g^(−1)),and a pure single-phase structure.In addition,high cooling rate(cooling in air or liq-N_(2)-quenching)was indispensable to obtain a single-phase rock-salt(Co,Cu,Mg,Ni,Zn)O because of phase separation caused by copper.By taking advantage of unique features of HEOs,rock-salt(Co,Cu,Mg,Ni,Zn)O can function as a promising candidate for lithium-ion batteries(LIBs)anode material,which achieved excellent cycling stability.This work provides a feasible synthetic strategy for low-dimensional hierarchical HEOs,which creates new opportunities for the stable HEOs being highly active functional materials.