Two‐Dimensional Transition Metal Oxides and Chalcogenides for Advanced Photocatalysis: Progress, Challenges, and Opportunities

Abstract

Sunlight‐driven catalytic reactions are appealing for resolving energy and environmental problems. Transition metal oxides (TMOs) and chalcogenides (TMCs) comprise one of the most popular categories of photocatalysts, thanks to their high stability, low cost, Earth abundance, and outstanding catalytic activity. Downsizing TMOs and TMCs to 2D materials offers additional opportunities to finely tune their surface, electronic, and catalytic properties. However, 2D TMOs and TMCs fall into a less mature field than other well‐established 2D materials. Less is known about their “form‐to‐function” relationship, and mechanisms for their synthesis await more research. Herein, the progress toward the rational design of layered and nonlayered 2D TMOs and TMCs is summarized, as well as principles to engineer their nanosheets (NSs) into 3D architectures for practical application. The formation mechanisms and crystal growth models of these 2D materials are included. The key factors that determine the electronic, surface structures, and catalytic properties of 2D TMOs and TMCs are examined in particular, which are key considerations in tuning their performance in light absorption, charge carrier transfer/separation, molecule capture and activation, etc. Finally, the present challenges and future research directions in this promising field are illustrated.

Emerging Cocatalysts on g‐C3N4 for Photocatalytic Hydrogen Evolution

“…Taking PtS as an example, PtS has a layered structure with massive exposed surfaces and highly active basal-plane sites, which implies the possibility of PtS as cocatalysts for HER. [112] Inspired by these properties of PtS, Liu et al [40] designed PtS/g-C 3 N 4 composite photocatalysts via in situ vapor-phase growth method (Figure 6a-c), and the as-made sample showed a high photocatalytic HER rate of 1072.6 µmol h −1 (Figure 6d), which is 13.3 times higher than Pt/g-C 3 N 4 , respectively. The authors claimed that the Schottky barrier was formed between C 3 N 4 and PtS with metallic property (Figure 6e,f), which rapidly extracted the photogenerated electrons from C 3 N 4 , thus improving the HER performance.…”

Oriented assembly of metal-organic frameworks and deficient TiO2 nanowires directed by lattice matching for efficient photoreversible color switching

“…This reversible transformation makes PB a good candidate as light-printing material [9,27]. Meanwhile, TiO 2 is one of the most promising catalysts to afford photo-generated electrons upon irradiation by light [28]. Because the edge of the con- duction band of rutile TiO 2 (ca.…”

The Role of Solar Energy (UV-VIS-NIR) as an Assistant for Sulfide Minerals Leaching and Its Potential Application for Metal Extraction

“…It is also feasible to explore its application as a direct photonic source for photochemical processes. Additionally, photons provided by sunlight (mainly UV and VIS radiation; additionally NIR light in photocatalysis) can be absorbed by a semiconductor material, such as natural doped compounds, sulfide minerals, and transition metal oxides, which are obtained from the ore bodies [16][17][18][19][20], generating excited states that give rise to a sequence of photochemical reactions (photooxidation/photoreduction) that can be exploited to improve or assist the oxidative dissolution of these sulfide minerals and accelerate ferric iron/ferrous cycling [21,22].…”