Photocatalytic Z‐Scheme Overall Water Splitting: Recent Advances in Theory and Experiments

Abstract

Photocatalytic water splitting is considered one of the most important and appealing approaches for the production of green H2 to address the global energy demand. The utmost possible form of artificial photosynthesis is a two‐step photoexcitation known as “Z‐scheme”, which mimics the natural photosystem. This process solely relies on the effective coupling and suitable band positions of semiconductors (SCs) and redox mediators for the purpose to catalyze the surface chemical reactions and significantly deter the backward reaction. In recent years, the Z‐scheme strategies and their key role have been studied progressively through experimental approaches. In addition, theoretical studies based on density functional theory have provided detailed insight into the mechanistic aspects of some breathtakingly complex problems associated with hydrogen evolution reaction and oxygen evolution reaction. In this context, this critical review gives an overview of the fundamentals of Z‐scheme photocatalysis, including both theoretical and experimental advancements in the field of photocatalytic water splitting, and suggests future perspectives.

Recent advances in solution assisted synthesis of transition metal chalcogenides for photo-electrocatalytic hydrogen evolution

“…The fabrication of heterojunctions in photocatalysts is among the most suitable strategies proposed to increase the lifespan of photogenerated electron–hole pairs. 175–178 A heterojunction is an interface formed between two semiconductors with different band gap energies. A difference in the band gaps of participating semiconductors is an essential feature for heterojunction formation (Fig.…”

Strategies of Anode Design for Seawater Electrolysis: Recent Development and Future Perspective

“…[ 3 ] Exploration of renewable energy resources like water is the potential candidate for a sustainable and safe future because it can be converted to green fuel (H 2 ) via electrocatalysis and can be used similarly to fossil fuels. [ 4 ] Water splitting (to break the O─H bond) is an energy‐intensive process. [ 5 ] Researchers have been practicing numerous technologies for electrochemical H 2 production to reduce the cost and increase efficiency, that is, alkaline water electrolysis, anion exchange membrane water electrolysis, proton exchange membrane water electrolysis, and solid oxide electrolysis.…”

Insight into the regulation between crystallinity and oxygen vacancies of BiVO4 affecting the photocatalytic oxygen evolution activity

“…1–6 Since Fujishima and Honda discovered that TiO 2 electrodes could split water into H 2 and O 2 under ultraviolet light in 1972, research, development and the mechanism of photocatalytic semiconductors have been the focus of people's attention. 7–11 The photocatalytic water splitting process mainly includes the hydrogen evolution reaction (HER: 2H + + 2e − → H 2 ) 12–15 and the oxygen evolution reaction (OER: 2H 2 O + 4e − → O 2 + 4H + ). 4,16–18 The OER is considered to be an important factor limiting the efficiency of photocatalytic water splitting because it involves complex four-electron and four-proton transfer and the formation of the O–O bond, which dynamically limits the photocatalytic water splitting.…”