Direct Z-scheme photocatalysts: Principles, synthesis, and applications

More than 95% (in volume) of all of today’s chemical products are manufactured through catalytic processes, making research into more efficient catalytic materials a thrilling and very dynamic rese...

Metal–Organic Frameworks in Heterogeneous Catalysis: Recent Progress, New Trends, and Future Perspectives

Metal–organic frameworks (MOFs), an emerging class of porous materials, have shown intriguing and promising properties in a wide range of applications due to their versatile structures, large surface areas, tunable porosity and tailorable chemistry. In recent years one of the most active research fields is to explore energy applications of MOF-based materials. In this review, we present a critical overview on the recent progress of the use of MOF-based materials for gaseous fuel storage, chemical hydrogen storage, solar and electrochemical energy storage and conversion. The challenges and opportunities towards advanced energy technologies with the MOF-based materials are discussed.

Metal–organic frameworks as a platform for clean energy applications

Two-dimensional MXenes: From morphological to optical, electric, and magnetic properties and applications

In recent years, a new large family of two dimensional transition metal carbides, carbonitrides, and nitrides, so-called MXenes, have grabbed considerable attention, owing to their many fascinating physical and chemical properties that are closely related to the rich diversity of their elemental compositions and surface terminations. In particular, it is easy for MXenes to form composites with other materials such as polymers, oxides, and carbon nanotubes, which further provides an effective way to tune the properties of MXenes for various applications. Not only have MXenes and MXene-based composites come into prominence as electrode materials in the energy storage field as is widely known, but they have also shown great potential in environment-related applications including electro/photocatalytic water splitting, photocatalytic reduction of carbon dioxide, water purification and sensors, thanks to their high conductivity, reducibility and biocompatibility. In this review, we summarize the synthesis and properties of MXenes and MXene-based composites and highlight their recent advances in environment-related applications. Challenges and perspectives for future research are also outlined.

MXene and MXene-based composites: synthesis, properties and environment-related applications

Inspired by natural photosynthesis, constructing inorganic/organic heterojunctions is regarded as an effective strategy to design high-efficiency photocatalysts. Herein, a step (S)-scheme heterojunction photocatalyst is prepared by in situ growth of an inorganic semiconductor firmly on an organic semiconductor. A new pyrene-based conjugated polymer, pyrene-alt-triphenylamine (PT), is synthesized via the typical Suzuki-Miyaura reactions, and then employed as a substrate to anchor CdS nanocrystals. The optimized CdS/PT composite, coupling 2 wt% PT with CdS, exhibits a robust H2 evolution rate of 9.28 mmol h-1 g-1 with continuous release of H2 bubbles, as well as a high apparent quantum efficiency of 24.3%, which is ≈8 times that of pure CdS. The S-scheme charge transfer mechanism between PT and CdS, is systematically demonstrated by photoirradiated Kelvin probe measurement and in situ irradiated X-ray photoelectron spectroscopy analyses. This work provides a protocol for preparing specific S-scheme heterojunction photocatalysts on the basis of inorganic/organic coupling.

An Inorganic/Organic S-Scheme Heterojunction H 2 -Production Photocatalyst and its Charge Transfer Mechanism

Water oxidation is the key process for many sustainable energy technologies containing artificial photosynthesis and metal–air batteries. Engineering inexpensive yet active electrocatalysts for water oxidation is mandatory for the cost-effective generation of solar fuels. Herein, we propose a novel hierarchical porous Ni–Co-mixed metal sulfide (denoted as NiCoS) on Ti3C2Tx MXene via a metal–organic framework (MOF)-based approach. Benefiting from the unique structure and strong interfacial interaction between NiCoS and Ti3C2Tx sheets, the hybrid guarantees an enhanced active surface area with prominent charge-transfer conductivity and thus a superior activity toward oxygen evolution reactions (OERs). Impressively, the hierarchical NiCoS in the hybrid is converted to nickel/cobalt oxyhydroxide–NiCoS assembly (denoted as NiCoOOH–NiCoS) by OER measurement, where NiCoOOH on the surface is confirmed as the intrinsic active species for the consequent water oxidation. The hybrid material is further applied to an ...

Metal–Organic Framework-Derived Nickel–Cobalt Sulfide on Ultrathin Mxene Nanosheets for Electrocatalytic Oxygen Evolution

Cocatalysts play an indispensable role in photocatalytic H2 production via water splitting for the conversion of solar energy into storable chemical energy. Herein, the hybrid catalyst CdS/Ag2S/NiS is synthesized via hydrothermal and photodeposition methods. CdS/Ag2S/NiS shows a drastically elevated hydrogen production rate of 48.3 mmol g−1 h−1 under visible light due to the combined merits of the Schottky junction between CdS and metal-like Ag2S and the constructed p–n junction between CdS and NiS. Time-resolved photoluminescence spectroscopy and photochemical tests reveal the accelerated charge transfer and significantly reduced electron–hole pair recombination. Further investigation with in-situ surface photovoltage imaging technology demonstrates that the reduction cocatalyst Ag2S and oxidation cocatalyst NiS can serve as photogenerated electron and hole traps, respectively. This research not only provides insight into designing high-efficiency photocatalyst for hydrogen production but also utilize a brand new method for the confirmation of charge–carrier migration pathways.

Bowen He

Papers

An Inorganic/Organic S-Scheme Heterojunction H 2 -Production Photocatalyst and its Charge Transfer Mechanism

Metal–Organic Framework-Derived Nickel–Cobalt Sulfide on Ultrathin Mxene Nanosheets for Electrocatalytic Oxygen Evolution

Enhancement in the photocatalytic H2 production activity of CdS NRs by Ag2S and NiS dual cocatalysts

NixSy Nanowalls/Nitrogen-Doped Graphene Foam Is an Efficient Trifunctional Catalyst for Unassisted Artificial Photosynthesis

Enhanced photocurrent density of HTM-free perovskite solar cells by carbon quantum dots