Photocatalytic and Photoelectrochemical Systems: Similarities and Differences

Abstract

Photocatalytic and photoelectrochemical processes are two key systems in harvesting sunlight for energy and environmental applications. As both systems are employing photoactive semiconductors as the major active component, strategies have been formulated to improve the properties of the semiconductors for better performances. However, requirements to yield excellent performances are different in these two distinctive systems. Although there are universal strategies applicable to improve the performance of photoactive semiconductors, similarities and differences exist when the semiconductors are to be used differently. Here, considerations on selected typical factors governing the performances in photocatalytic and photoelectrochemical systems, even though the same type of semiconductor is used, are provided. Understanding of the underlying mechanisms in relation to their photoactivities is of fundamental importance for rational design of high‐performing photoactive materials, which may serve as a general guideline for the fabrication of good photocatalysts or photoelectrodes toward sustainable solar fuel generation.

Recent advances in photodegradation of antibiotic residues in water

“…The formation of homojunctions is considerably challenging owing to its complexity and high cost. Therefore, the creation of heterojunction interfaces has been proposed as an alternative to improve charge separation efficiency and has been widely investigated in the past decades [281] . Typically, heterojunctions are divided into five categories: (1) Schottky heterojunctions, (2) type I heterojunctions, (3) type II heterojunctions, (4) p-n heterojunctions, and (5) Z-scheme heterojunctions.…”

Complex Catalytic Materials Based on the Perovskite-Type Structure for Energy and Environmental Applications

“…In this way, the resulting gas can be independently collected with no further costly gas separation methods or efficiency lowering because of SBR. Furthermore, appropriate and superior quality contact between the conductive substrate and semiconductor ensures excellent charge transfer leading to great photoelectrochemical efficiencies [168].…”

“…The working principle of the reaction in the presence of photocatalysts (A) and photocurrent density vs. the applied potential curves of photoelectrodes (B) loaded with an oxidation co-catalyst for both dark and illuminated processes, where OC-oxidation cocatalyst, E uncat -activation energy without OC and E cat -activation energy with OC. Adapted from references [168,228].…”

Atomic Sulfur Passivation Improves the Photoelectrochemical Performance of ZnSe Nanorods

“…It is ever important to establish efficient photocatalytic water splitting systems, in order to obtain clean and easily storable hydrogen fuels for solving energy and environment issues [ 1 , 2 ]. Compared with semiconductor powder-based photocatalytic water splitting systems, photoelectrochemical (PEC) cells can effectively suppress the backward reactions, thus enabling us to collect hydrogen more easily [ 3 , 4 , 5 ]. The photocatalyst is at the core of PEC cells, and thus extensive efforts have been devoted to the development of abundant, inexpensive, nontoxic, and efficient photocatalysts [ 6 , 7 , 8 , 9 , 10 , 11 , 12 ].…”