A Critical Review on Energy Conversion and Environmental Remediation of Photocatalysts with Remodeling Crystal Lattice, Surface, and Interface

Abstract

Solar energy is a renewable resource that can supply our energy needs in the long term. A semiconductor photocatalysis that is capable of utilizing solar energy has appealed to considerable interests for recent decades, owing to the ability to aim at environmental problems and produce renewal energy. Much effort has been put into the synthesis of a highly efficient semiconductor photocatalyst to promote its real application potential. Hence, we reviewed the most advanced methods and strategies in terms of (i) broadening the light absorption wavelengths, (ii) design of active reaction sites, and (iii) control of the electron−hole (e − -h + ) recombination, while these three processes could be influenced by remodeling the crystal lattice, surface, and interface. Additionally, we individually examined their current applications in energy conversion (i.e., hydrogen evolution, CO 2 reduction, nitrogen fixation, and oriented synthesis) and environmental remediation (i.e., air purification and wastewater treatment). Overall, in this review, we particularly focused on advanced photocatalytic activity with simultaneous wastewater decontamination and energy conversion and further enriched the mechanism by proposing the electron flow and substance conversion. Finally, this review offers the prospects of semiconductor photocatalysts in the following three vital (distinct) aspects: (i) the large-scale preparation of highly efficient photocatalysts, (ii) the development of sustainable photocatalysis systems, and (iii) the optimization of the photocatalytic process for practical application.

Atomic‐Level and Modulated Interfaces of Photocatalyst Heterostructure Constructed by External Defect‐Induced Strategy: A Critical Review

“…Various strategies have been proposed to develop such a system. [ 3 ] To achieve this goal, it is extremely important to consider the electron migration across the photocatalyst interface, which can strongly impact the charge separation and solar conversion efficiencies. Appropriately engineered photocatalyst heterostructures may facilitate the photocatalyst development process and satisfy the requirements of efficient carrier separation.…”

Enhancing the Photocatalytic Activity of TiO2 Catalysts

“…As a photocatalyst, TiO 2 has been investigated to degrade organic pollutants and to produce fuels from water and carbon dioxide (CO 2 ). [9][10][11][12][13] For photocatalytic fuel production, appropriate band position, fast charge mobility, and suppression of charge recombination are essential. Although several obstacles to realizing efficient photocatalytic activity remain, the main challenges for TiO 2 -based photocatalysts are systems are discussed.…”

Photosensitive Hybrid Nanostructured Materials: The Big Challenges for Sunlight Capture

“…With this aim, photocatalytic processes have been developed and employed in different technological fields. Particularly, they exploit semiconductor materials to carry out photo-driven redox reactions for a huge number of applications, such as hydrogen production by water splitting, CO 2 capture and reduction to fuel molecules, pollutants degradation, as well as organic syntheses [4][5][6][7][8]. From a mechanistic point of view, irradiating a photocatalyst by UV/visible light with energy equal or higher than its bandgap, electrons (e − ) can jump from the valence band (VB) into the conduction band (CB) and leave holes (h + ), generating electron-hole pairs.…”

“…Furthermore, the recombination of excited electron/hole pairs can occur, limiting the reactivity (Figure 1a). Light absorption by inorganic semiconductor photocatalysts is usually restricted to the ultraviolet (UV) range, and it is hard to extend their absorption features to the visible light range, only through the modification of their structures [6][7][8]. Also, the charge-recombination phenomena are recurrent.…”

“…The most attractive solutions to improve the photocatalytic performances of oxide-based systems rely on: (i) dye sensitization, (ii) charge transfer complex sensitization, (iii) heterostructures formation, frequently including carbon-based components, and (iv) metal and non-metal doping [7][8][9][10]. Doping of TiO 2 and other oxides has already been extensively investigated and reviewed.…”