As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and “earth-abundant” nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The constructi...

Graphitic Carbon Nitride (g-C3N4)-Based Photocatalysts for Artificial Photosynthesis and Environmental Remediation: Are We a Step Closer To Achieving Sustainability?

Semiconductor-based photocatalysis is considered to be an attractive way for solving the worldwide energy shortage and environmental pollution issues. Since the pioneering work in 2009 on graphitic carbon nitride (g-C3N4) for visible-light photocatalytic water splitting, g-C3N4 -based photocatalysis has become a very hot research topic. This review summarizes the recent progress regarding the design and preparation of g-C3N4 -based photocatalysts, including the fabrication and nanostructure design of pristine g-C3N4 , bandgap engineering through atomic-level doping and molecular-level modification, and the preparation of g-C3N4 -based semiconductor composites. Also, the photo-catalytic applications of g-C3N4 -based photocatalysts in the fields of water splitting, CO2 reduction, pollutant degradation, organic syntheses, and bacterial disinfection are reviewed, with emphasis on photocatalysis promoted by carbon materials, non-noble-metal cocatalysts, and Z-scheme heterojunctions. Finally, the concluding remarks are presented and some perspectives regarding the future development of g-C3N4 -based photocatalysts are highlighted.

Polymeric Photocatalysts Based on Graphitic Carbon Nitride

A review on g-C3N4-based photocatalysts

Photocatalysis is considered as one of the promising routes to solve the energy and environmental crises by utilizing solar energy. Graphitic carbon nitride (g-C3N4) has attracted worldwide attention due to its visible-light activity, facile synthesis from low-cost materials, chemical stability, and unique layered structure. However, the pure g-C3N4 photocatalyst still suffers from its low separation efficiency of photogenerated charge carriers, which results in unsatisfactory photocatalytic activity. Recently, g-C3N4-based heterostructures have become research hotspots for their greatly enhanced charge carrier separation efficiency and photocatalytic performance. According to the different transfer mechanisms of photogenerated charge carriers between g-C3N4 and the coupled components, the g-C3N4-based heterostructured photocatalysts can be divided into the following categories: g-C3N4-based conventional type II heterojunction, g-C3N4-based Z-scheme heterojunction, g-C3N4-based p–n heterojunction, g-C3N4/metal heterostructure, and g-C3N4/carbon heterostructure. This review summarizes the recent significant progress on the design of g-C3N4-based heterostructured photocatalysts and their special separation/transfer mechanisms of photogenerated charge carriers. Moreover, their applications in environmental and energy fields, e.g., water splitting, carbon dioxide reduction, and degradation of pollutants, are also reviewed. Finally, some concluding remarks and perspectives on the challenges and opportunities for exploring advanced g-C3N4-based heterostructured photocatalysts are presented.

g-C3N4-Based Heterostructured Photocatalysts

S-Scheme Heterojunction Photocatalyst

Recently, CdS has been intensively investigated for its excellent photocatalytic hydrogen (H2) evolution property. However, the poor stability and serious photocorrosion severely influence its potential for practical application. In this work, we successfully synthesized Bi surface plasmon resonance (SPR)-promoted Z-scheme Bi2MoO6 nanosheet/CdS-diethylenetriamine (Bi–Bi2MoO6/CdS-DETA) composites via an in situ solvothermal method. Crystalline structure, morphology, electrochemical properties, along with the photocatalytic H2 evolution activity and stability, have been systematically investigated. The as-prepared Bi–Bi2MoO6/CdS-DETA composites with optimized structure exhibited advanced photocatalytic H2 evolution activity (reach to 7.37 mmol h–1 g–1) and high stability. Largely exposed active sites, effective Z-scheme charge separation and Bi metal SPR effect of the two-dimension (2D) heterostructure is contributed to improve H2 generation performance of Bi–Bi2MoO6/CdS-DETA composites. This work provides ...

Bi SPR-Promoted Z-Scheme Bi2MoO6/CdS-Diethylenetriamine Composite with Effectively Enhanced Visible Light Photocatalytic Hydrogen Evolution Activity and Stability

A novel step-scheme BiVO4/Ag3VO4 photocatalyst for enhanced photocatalytic degradation activity under visible light irradiation

Integrated S-Scheme Heterojunction of Amine-Functionalized 1D CdSe Nanorods Anchoring on Ultrathin 2D SnNb2O6 Nanosheets for Robust Solar-Driven CO2 Conversion

Noble-metal-free bimetal-based electrocatalysts have shown high efficiency for water oxidation. Ni and/or Co in these electrocatalysts are essential to provide a conductive, high-surface area and a chemically stable host. However, the necessity of Ni or Co limits the scope of low-cost electrocatalysts. Herein, we report a hierarchical hollow FeV composite, which is Ni- and Co-free and highly efficient for electrocatalytic water oxidation with low overpotential 390 mV (10 mA cm−2 catalytic current density), low Tafel slope of 36.7 mV dec−1, and a considerable durability. This work provides a novel and efficient catalyst, and greatly expands the scope of low-cost Fe-based electrocatalysts for water splitting without need of Ni or Co.

Jinfeng Zhang

Papers

Bi SPR-Promoted Z-Scheme Bi2MoO6/CdS-Diethylenetriamine Composite with Effectively Enhanced Visible Light Photocatalytic Hydrogen Evolution Activity and Stability

A novel step-scheme BiVO4/Ag3VO4 photocatalyst for enhanced photocatalytic degradation activity under visible light irradiation

Integrated S-Scheme Heterojunction of Amine-Functionalized 1D CdSe Nanorods Anchoring on Ultrathin 2D SnNb2O6 Nanosheets for Robust Solar-Driven CO2 Conversion

Hollow Iron–Vanadium Composite Spheres: A Highly Efficient Iron‐Based Water Oxidation Electrocatalyst without the Need for Nickel or Cobalt

Facile synthesis of Z-scheme graphitic-C3N4/Bi2MoO6 nanocomposite for enhanced visible photocatalytic properties