Recent advances in the synthesis and electrocatalytic application of MXene materials

Abstract

MXene is a kind of two-dimensional material with graphene-like structure, which has excellent optical, biological, thermodynamic, electrical and magnetic properties. Due to the diversity of combination of transition metals and...

Overall Spontaneous Water Splitting for Calcium Bismuthate Ca(BiO2)2: Flexible-Electronic-Controlled Band Edge Position and Adsorption-Site-Modulated Bond Strength

“…In contrast to the oxidation reaction, the first step of the hydrogen evolution half reaction is downhill, indicating that the Ca(BiO 2 ) 2 monolayer undergoes self-exothermic reaction during the process of combining a proton and an electron to form H* without requiring external energy input. This is similar to the free energy curves generated by hydrogen evolution reactions for the SiS/ZnO heterojunction, 72 MXene, and MXene derivatives 73 and at different reaction sites on the WS 2 /Co 9 S 8 heterojunction. 74 However, the reduction of H 2 from the intermediate state H* in the second step is impeded by a high barrier of 1.84 and 2.26 eV in an acidic (pH 0, black lines) and neutral (pH 7, blue lines) dark environment (light off), resulting in photogenerated holes generating only a potential of 0.48 V even when the Ca(BiO 2 ) 2 monolayer at pH 0 is exposed to light (light on), requiring an additional absorption of 1.85 eV (red lines).…”

Ni3Se4/Fe(PO3)2/NF composites as high-efficiency electrocatalysts with a low overpotential for the oxygen evolution reaction

“…However, because the OER reaction has multi-electron transfer steps with multiple active intermediates, the reaction is complex and needs to cross a large energy barrier, 2 the overpotential is often more than twice that of the HER reaction, and the energy conversion rate is greatly limited, 9,10 increasing the electrical energy consumption; 8 thus, the voltage required for water electrolysis is much larger than the theoretical voltage of water decomposition (1.23 V vs. the reversible hydrogen electrode (RHE)), 11 which is an important reason for the competitive disadvantage of hydrogen production from water electrolysis compared with traditional fossil energy hydrogen production. 12 Therefore, it is of great significance to find low-cost electrocatalysts with superior OER activity and stability, reduce the overpotential of the OER, and solve the bottleneck of slow OER half-reaction kinetics. Generally, catalysts with appropriate metal–oxygen bond strength, such as noble metal oxides, IrO 2 , and RuO 2 , have excellent OER catalytic activity.…”

Constructing a Functionalized Electrocatalyst of a Transition Metal Chalcogenide on Accordion-Like MXene to Boost the Hydrogen Evolution Reaction

“…So far, many promising candidates besides TMC have shown excellent performance in the field of electrocatalysis. In recent years, emerging MXenes, such as Ti 3 C 2 MXene, have received widespread attention because of their good electrical conductivity and special layer-by-layer structures. − These distinctive structures can provide a large surface area, which ensures sufficient active sites. , In addition, excellent conductivity can improve electron transfer ability. , The abundant surface functional groups of MXenes are conducive to optimal chemical affinity . Furthermore, MXenes with hydrophilic surface functional groups can improve the transport speed of ions in liquid electrolytes .…”