Interface Engineering for Modulation of Charge Carrier Behavior in ZnO Photoelectrochemical Water Splitting

Abstract

Photoelectrochemical water splitting via consumption of solar energy is considered an alternative approach to address both fossil resource and global warming issues. On the basis of the bottom‐up technique, major strategies have been developed to enrich the complexity of nanostructures by incorporating various functional components to realize outstanding photoelectrochemical (PEC) performance for hydrogen evolution, such as high solar‐to‐hydrogen efficiency and long‐term stability. In such a PEC system, each nanomaterial component individually, and more importantly, together with the formed interfaces, contributes to PEC performance elevation. Specifically, the two types of interfaces that have emerged, i.e., the interfaces between photoelectrodes and electrolytes (solid–liquid contact) and the interfaces inside photoelectrodes (solid–solid contact), have both been effectively engineered to facilitate charge separation and transportation and even enhance the antiphotocorrosion properties. A comprehensive understanding, summary, and review of such interface engineering protocols may provide novel and effective approaches for PEC system designing.

Advances in Piezo‐Phototronic Effect Enhanced Photocatalysis and Photoelectrocatalysis

“…Wurtzite zinc oxide (space group P 6 3 mc ) semiconductor, with a high mobility of 210 cm 2 V −1 s −1 and a direct bandgap of 3.3 eV, is extensively investigated in photo(electro)catalytic processes. [ 59 ] Despite the efforts have been made toward band structure and surface structure engineering, ZnO based systems still suffer from low charge‐separation efficiency. Since ZnO is also a typical piezoelectric material, the electronic band structure can be modulated by means of piezoelectric polarization.…”

An Efficient Strategy for Boosting Photogenerated Charge Separation by Using Porphyrins as Interfacial Charge Mediators

“…Photoelectrochemical (PEC) water splitting is an environmentally friendly and renewable approach for the conversion of solar power into chemical energy . The PEC process is mainly divided into three steps, including adequate light harvesting, effective charge separation, and a fast surface reaction .…”

“…We describe herein an ovel charge transfer system designed with BiVO 4 as ap rototype.I nt his system, porphyrins act as an interfacial-charge-transfer mediator,l ike avolleyball setter,toefficiently suppress surface recombination through higher hole-transfer kinetics rather than as atraditional photosensitizer.Furthermore,wefound that the introduction of a" setter" can ensure al ong lifetime of charge carriers at the photoanode/electrolyte interface.This simple interface chargemodulation system exhibits increased photocurrent density from 0.68 to 4.75 mA cm À2 and provides ap romising design strategy for efficient photogenerated charge separation to improve PEC performance.Photoelectrochemical (PEC) water splitting is an environmentally friendly and renewable approach for the conversion of solar power into chemical energy. [1][2][3][4] TheP EC process is mainly divided into three steps, [5][6][7][8][9] including adequate light harvesting,e ffective charge separation, and af ast surface reaction. [10,11] Unfortunately,many photocatalysts suffer from severe surface recombination [12] at the photoanode/electrolyte junction, which significantly hampers their application in photocatalytic and photoelectrocatalytic systems.Recently,b yl oading oxygen evolution cocatalysts (OECs), such as transition-metal (Fe, Co,N i) oxides and hydroxides (i.e., binary and ternary compounds), on the photoanodes (e.g.,n -Fe 2 O 3 , [13,14] n-BiVO 4 , [15] WO 3 [16] ), the PEC performance could be enhanced.…”

“…Photoelectrochemical (PEC) water splitting is an environmentally friendly and renewable approach for the conversion of solar power into chemical energy. [1][2][3][4] TheP EC process is mainly divided into three steps, [5][6][7][8][9] including adequate light harvesting,e ffective charge separation, and af ast surface reaction. [10,11] Unfortunately,many photocatalysts suffer from severe surface recombination [12] at the photoanode/electrolyte junction, which significantly hampers their application in photocatalytic and photoelectrocatalytic systems.…”

An Efficient Strategy for Boosting Photogenerated Charge Separation by Using Porphyrins as Interfacial Charge Mediators

“…Photoelectrochemical (PEC) water splitting is an environmentally friendly and renewable approach for the conversion of solar power into chemical energy . The PEC process is mainly divided into three steps, including adequate light harvesting, effective charge separation, and a fast surface reaction .…”