Heterostructures in two-dimensional colloidal metal chalcogenides: Synthetic fundamentals and applications

A Review of the Effects of Electrode Fabrication and Assembly Processes on the Structure and Electrochemical Performance of 2D MXenes

“…In the case of solution‐processed 2D materials such as rGO and MXene, the 2D flakes tend to restack to form multilayers during various stages of materials synthesis and electrode fabrication process. This significantly limits the accessibility of electrolyte ions to the electrode surfaces, [ 17,37,38,43,44,90–92,93 ] leading to a fading capacitive performance at high charge/discharge rates. [ 21,26,27,94 ] Therefore, engineering the structure of the electrodes to prevent restacking through novel material assembly and electrode fabrication processes has been a major theme of research in this area.…”

“…In recent years, 2D materials with high surface areas have been the forerunners in search of candidate electrode materials for advanced ECs. [ 14–17 ] Some 2D materials offer an abundance of electrochemically active surfaces, which combined with high electrical conductivity, leads to fast electrochemical charge storage and high energy and power densities of the electrodes. [ 16–19 ] 2D transition metal carbides and nitrides, MXenes, are prime examples of such electrode materials.…”

Z‐Scheme Photocatalytic Systems for Carbon Dioxide Reduction: Where Are We Now?

“…[35,36] Evidently,t he fast charge transfer route of Ty pe II heterojunction systems can suppress the rapid recombination of photogenerated electron-hole pairs and promote their spatial separation, which can considerably improve the photoconversion efficiency of solar energy. [37] However,t he charge separation in the Ty pe II heterojunction is promoted by sacrificing those photogenerated charge carriers with strong redox abilities,w hich is unfavorable for CO 2 photoreduction reactions with high thermodynamic requirements.Hence,itis imperativetodelve into more efficient photocatalytic systems that concurrently possess superior redox capabilities,h igh light utilization and electron-hole separation efficiencyfor CO 2 reduction.…”

“…The Type II heterojunction (Figure 1 b) is one of the most typical heterostructures owing to its common occurrence in heterojunction structures [35, 36] . Evidently, the fast charge transfer route of Type II heterojunction systems can suppress the rapid recombination of photogenerated electron‐hole pairs and promote their spatial separation, which can considerably improve the photoconversion efficiency of solar energy [37] . However, the charge separation in the Type II heterojunction is promoted by sacrificing those photogenerated charge carriers with strong redox abilities, which is unfavorable for CO 2 photoreduction reactions with high thermodynamic requirements.…”

Selective Growth of Metal Sulfide, Metal, and Metal-Alloy on 2D CdS Nanoplates

“…During the last decade, colloidal (quasi) two-dimensional (2D) nanoplates or nanoplatelets (NPLs) have attracted much attention because of their unique electronic and optical properties (Ithurria et al, 2011a,b;Nasilowski et al, 2016;Kelestemur et al, 2017;Akkerman et al, 2019;Ganguly et al, 2019). At present, the research on 2D colloidal semiconductors is thriving, with various compositions (Wang et al, 2014;Berends et al, 2018;Akkerman et al, 2019;Dufour et al, 2019) and nanoscale interfaces are explored including van der Waals heterostructures, core-shell, and core-crowns in the case of SC-SC (Davis et al, 2019;Li et al, 2019;Min et al, 2019;Saidzhonov et al, 2019) and various decoration locations and amounts in the case of SC-M. Of note is the ability of metal ions to induce shape control as well as determine final composition (e.g., CuS-Ag 2 S or Ag 2 S-Ag; Liu et al, 2018). Among the II-VI nanomaterials, and cadmium chalcogenides (Kormilina et al, 2017;Li and Lian, 2018) in particular, CdS is explored due to its controllable morphology, electronic structure, and optical properties.…”