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?

Engineering photocatalytic materials for renewable energy generation and environmental decontamination has always been a very exciting prospect to counter the global energy demands and pollution challenges. Graphitic carbon nitride (g-C 3 N 4 ), a polymeric, metal-free semiconductor with a mild band gap (2.7 eV) has become hot-spot in various scientific exploits such as environmental pollution mitigation, energy generation and storage, organic synthesis, sensors, etc. These applications exploit the interesting properties of g-C 3 N 4 such as good visible light absorption, graphene-like structure, good thermal and chemical stability and photocatalytic properties. In this review we begin with an overview of the fundamental aspects of photocatalysis as a pollution remediation strategy. This is followed by an introduction to graphitic carbon nitride as a photocatalyst, preparation strategies and its properties. Subsequently, a comprehensive and critical discussion of the various most recent developments towards enhancing the visible light photocatalytic properties of g-C 3 N 4 for pollution alleviation, selected results and important photocatalytic degradation mechanisms, is given. Summary remarks and future perspective conclude the review.

Graphitic carbon nitride (g-C3N4) nanocomposites: A new and exciting generation of visible light driven photocatalysts for environmental pollution remediation

Surface reaction kinetics and bulk charge separation are both critical to the efficiency of solar water splitting. In addition to the well-documented surface catalytic effect, the promotion of bulk charge separation upon loading of cocatalysts has rarely been reported. This paper describes the synergetic enhancement of surface reaction kinetics and bulk charge separation by introducing discrete nanoisland p-type Co3O4 cocatalysts onto n-type BiVO4, forming a p–n Co3O4/BiVO4 heterojunction with an internal electric field to facilitate charge transport. Being highly dispersed on the surface of photoanodes, the nanoisland cocatalysts could suppress the formation of recombination centers at the photoanode/cocatalyst interface. This cocatalyst-loading method achieved a charge separation efficiency of up to 77% in the bulk and 47% on the surface of catalysts. An AM 1.5G photocurrent of 2.71 mA/cm2 at 1.23 V versus the reversible hydrogen electrode for water oxidation was obtained, which is the highest photocurr...

Enhanced Surface Reaction Kinetics and Charge Separation of p-n Heterojunction Co3O4/BiVO4 Photoanodes.

A review on TiO 2 -based Z-scheme photocatalysts

Bismuth vanadate (BiVO4) is a promising visible-light driven semiconductor photocatalyst with various benefits such as low production cost, low toxicity, high photostability, resistance to photo-corrosion and narrow band gap with a good response to visible-light excite. However, the fast recombination of photoinduced charge carriers restricts their photocatalytic activity. In the past decades, many attempts were adopted to enhance the photocatalytic activity of BiVO4. Significant advances in understanding the fundamental issues and the development of an efficient photocatalyst have been made in current years. In this review, we have provided a comprehensive overview of the latest progress on the morphology control and growth mechanism of BiVO4 micro/nano-structures, doping with metal and non-metal elements and semiconductor coupling along with some highlights in the photodegradation of organic pollutants under visible-light illumination. This review may benefit the researchers and engineers in the arena of material chemistry for designing new BiVO4 based photocatalysts with low production cost and high efficiency.

A review on BiVO4 photocatalyst: Activity enhancement methods for solar photocatalytic applications

Optimization of the multiferroic BiFeO3 thin films by divalent ion (Mn, Ni) co-doping at B-sites

BiPO4@glucose-based C core–shell nanorod heterojunction photocatalyst with enhanced photocatalytic activity

Er3+-doped BiVO4 with tetragonal structure is prepared by the microwave hydrothermal method. X-ray diffraction and Rietveld refinement demonstrate that the structure is transformed from the monoclinic (C2/c:c3) phase to the tetragonal (I41/amd:2) phase by doping with Er3+ ions. Er3+ doping also influences the morphology change of BiVO4 from irregular flake-like crystal to rod-like crystal, which leads to the increase of the surface areas from 3.25 to 11.96 m2 g−1. Compared with the monoclinic BiVO4, the upconversion of the Er3+-doped tetragonal BiVO4 occurs through the transitions from the 4I15/2 ground state to 4F7/2, 2H11/2, and 4F9/2 states, respectively. The photocatalytic experiment indicates that the tetragonal BiVO4 (8 at.%) with a larger specific surface area (9.88 m2 g−1) shows the best photocatalytic activity under visible light irradiation, which can efficiently improve the degradation rate of RhB up to 97.2% at 150 min.

Huijun Ren

Papers

Optimization of the multiferroic BiFeO3 thin films by divalent ion (Mn, Ni) co-doping at B-sites

BiPO4@glucose-based C core–shell nanorod heterojunction photocatalyst with enhanced photocatalytic activity

The upconversion and enhanced visible light photocatalytic activity of Er3+-doped tetragonal BiVO4

Electric fields and local magnetic field enhance Ag-BiVO4-MnOx photoelectrochemical and photocatalytic performance

Controllable synthesis of Sm2O3 crystallites with the assistance of templates by a hydrothermal–calcination process