MXene Anion Engineering for Efficient Hydrogen Evolution

Abstract

MXenes have attracted attention as promising electrocatalysts for performing the hydrogen evolution reaction (HER). However, the poor intrinsic kinetics and inadequate density of active sites restrict MXenes as viable electrocatalysts for efficient hydrogen production. Herein, these hindrances are overcome via tunable doping of anion atoms as electron donors in titanium carbide (Ti3C2T X ) MXenes. By engineering the co-doping of nitrogen and sulfur anions, we achieve efficient electrocatalytic activity through synergistic chemical and structural changes. The modified MXene offers an optimal concentration of Ti–S and Ti–N bonds at the surface of hexagonal nanoplate-decorated nanosheets, resulting in a low overpotential of 260 mV and a Tafel slope of 85 mV/dec in an acidic medium, which is improved 3× over that of the pristine MXene (overpotential of 770 mV). This modified Ti3C2T X catalyst also displays superior durability compared with other earth-abundant catalysts, showing an operation for 60 h of continuous hydrogen evolution without any decay in its performance. The enhanced electrocatalytic activity of anion-co-doped Ti3C2T X MXene is attributed to manipulation of the electronic structure through synergistic N and S bonding, which promotes balanced adsorption/desorption of the intermediate hydrogen H* by lowering the Gibbs free energy (ΔG H* = −0.07 eV). Our strategy to improve the electrocatalytic activity of Ti3C2T X by anion engineering has the potential to enhance the electrocatalytic activity of numerous MXenes as well as other high surface area 2D materials.

Biocompatible 3D Printed MXene Microlattices for Tissue‐Integrated Antibiotic Sensing

“…Details of this specific MXene synthesis can be seen in the recent publication. [ 45 ] The Ti 3 C 2 T x ‐MXene solution with a concentration of 1 mg mL −1 was obtained by sonication for 30 min. Lastly, the ALD‐coated 3D polymer lattice microstructure was submerged in the MXene solution and sonicated for 30 min.…”

Electrolysis of Seawater: An Effective Path to Sustainable Hydrogen Production with Sulfur-Doped NiFe LDH/MXene@NF Electrodes

“…Therefore, to develop novel materials with high catalytic properties, high conductivity, hydrophilicity, and electrocatalytic activity must be achieved. Over the past decade, MXene, a novel metal carbide prepared by selective etching and stripping of the MAX phase, has entered the field of advanced electrocatalysts as an emerging two-dimensional (2D) material. , The general formula for MXene is usually written as M n +1 X n T x ( n = 1–3), where M, X, and T are transition metals (e.g., Ti, V, and Nb), carbon or nitrogen, and terminal functional groups (−O, −OH, and/or -F), respectively. , Its fascinating properties, including high conductivity, good hydrophilicity, and abundant modified terminal groups, enable electrocatalysts to be firmly anchored to surfaces and further modulate the electronic structure and the ability to transfer electrons between interfaces and thus have been used to construct a variety of composite materials in electrochemical catalysis. ,, For example, Li’s team designed a Ru/MXene three-dimensional electrode with synergistic control of the active site, electrolyte wetting, and gas release . Chanda et al optimized the adsorption energy of hydrogen evolution reaction (HER) and OER reaction intermediates by constructing a multifunctional synergistic catalytic interface between NiFeS and MXene, and it exhibited good water splitting performance in alkaline membrane water electrolyzers .…”

“…23,24 Its fascinating properties, including high conductivity, good hydrophilicity, and abundant modified terminal groups, enable electrocatalysts to be firmly anchored to surfaces and further modulate the electronic structure and the ability to transfer electrons between interfaces and thus have been used to construct a variety of composite materials in electrochemical catalysis. 16,25,26 For example, Li's team designed a Ru/MXene three-dimensional electrode with synergistic control of the active site, electrolyte wetting, and gas release. 27 Chanda et al optimized the adsorption energy of hydrogen evolution reaction (HER) and OER reaction intermediates by constructing a multifunctional synergistic catalytic interface between NiFeS and MXene, and it exhibited good water splitting performance in alkaline membrane water electrolyzers.…”