In a groundbreaking study reported on March 28, 2025, in the prestigious journal Nature Synthesis, researchers achieved a significant breakthrough in the field of materials science. By employing precise etching techniques guided by theoretical computations, they successfully obtained atomically ordered W2TiC2Tx MXene, a novel two-dimensional material. This achievement revolutionizes the challenges associated with interlayer delamination, paving the way for innovative applications of MXene powder in various fields, particularly in hydrogen production through water electrolysis.
Innovative Synthesis Method:
By utilizing Density Functional Theory (DFT) calculations, the researchers explored the feasibility of etching tungsten layers in (W,Ti)4C4₋y compounds. They discovered that excess aluminum doping (2Al precursor) helps reduce oxygen impurities and facilitates selective etching. Through selective etching of covalently bonded tungsten layers from non-MAX layered carbide (W,Ti)4C4-y precursors using HCl-LiF, they successfully synthesized ordered bimetallic transition metal MXene (W2TiC2Tx).
Exceptional Hydrogen Evolution Reaction (HER) Performance:
The delaminated W2TiC2Tx MXene exhibited outstanding HER performance, with an overpotential of only 144mV at a current density of 10mA cm-2, surpassing the existing W1.33CtX MXene. DFT calculations showcased that the hydrogen adsorption free energy on the tungsten-titanium mixed surface (W-Ti3 coordination sites) approaches thermal neutrality (ΔGad=-0.37eV), outperforming pure tungsten surfaces (ΔGad=-1.79eV).
Versatile Material Properties:
Additionally, this material boasts a high room temperature electrical conductivity of 427 Scm-1, following the Variable Range Hopping (VRH) model, indicating predominant interlayer electron transport. It exhibits saturable absorption behavior under 800nm femtosecond laser irradiation, highlighting its potential value in photonic and laser applications. The high conductivity and stability of this material make it a promising candidate for a wide range of optoelectronic and laser technologies.
This study breaks through the traditional synthesis paradigm of MXene and provides new ideas for constructing efficient HER catalysts and novel 2D materials.
Literature name: Synthesis of a 2D tungsten MXene for electrocatalysis
