Quantum Dots Compete at the Acme of MXene Family for the Optimal Catalysis

Abstract

It is well known that two-dimensional (2D) MXene-derived quantum dots (MQDs) inherit the excellent physicochemical properties of the parental MXenes, as a Chinese proverb says, “Indigo blue is extracted from the indigo plant, but is bluer than the plant it comes from.” Therefore, 0D QDs harvest larger surface-to-volume ratio, outstanding optical properties, and vigorous quantum confinement effect. Currently, MQDs trigger enormous research enthusiasm as an emerging star of functional materials applied to physics, chemistry, biology, energy conversion, and storage. Since the surface properties of small-sized MQDs include the type of surface functional groups, the functionalized surface directly determines their performance. As the Nobel Laureate Wolfgang Pauli says, “God made the bulk, but the surface was invented by the devil,” and it is just on the basis of the abundant surface functional groups, there is lots of space to be thereof excavated from MQDs. We are witnessing such excellence and even more promising to be expected. Nowadays, MQDs have been widely applied to catalysis, whereas the related reviews are rarely reported. Herein, we provide a state-of-the-art overview of MQDs in catalysis over the past five years, ranging from the origin and development of MQDs, synthetic routes of MQDs, and functionalized MQDs to advanced characterization techniques. To explore the diversity of catalytic application and perspectives of MQDs, our review will stimulate more efforts toward the synthesis of optimal MQDs and thereof designing high-performance MQDs-based catalysts.

Emerging carbon-based quantum dots for sustainable photocatalysis

“…3e). 45–49 Since the MAX and MXene phases have hexagonal symmetry structures, the derived MQD systems form hexagonal lattices with the same symmetry. 50–56 Zeng et al established a hexagonal cluster MQD model for DFT calculations, in which the size of the model was on the brink of the experimental size; this proved the reliability of the calculation results.…”

Transition metal quantum dots for the electrocatalytic hydrogen evolution reaction: recent progresses and challenges

“…104 It is evident from an MQD system that a non-metallic atom with enhanced electronegativity is preferably selected to passivate the MQD active sites efficiently. 105 Mei et al in 2019 discussed the enriched optical properties that are colour tuned, made of cadmium-free transition metal ions that are doped with InP/ZnS quantum dots. This work inculcated a nucleation doping method via an organic synthetic pathway wherein a series of transition metals co-doped with InP/ZnS quantum dots with variable colour-tuned optical properties were synthesized.…”

“…The use of MQDs for the heterostructure composite is a strategy to tune the band gap and improve the catalytic efficiency. 105 Mo 2 C QDs and WC QDs incorporated with N-doped graphene nanosheets have been reported for HER. The catalyst shows good durability and high exchange current density.…”

Hydrogen Production Technology Promotes the Analysis and Prospect of the Hydrogen Fuel Cell Vehicles Development under the Background of Carbon Peak and Carbon Neutrality in China

“…Interestingly, transition group metals (Fe, Co, Ni, Cu, etc.) expected to be substitutes for noble metal catalysts due to the merits of unique d-orbital electronic structures and good electronic conductivity. − In addition, the interaction between transition group metals and hydrogen atoms is unfavorable to the catalytic reaction based on the description of the HER volcano diagram. The design of transition group metals is necessary for preparing high-performance electrocatalysts.…”