Advances in Z‐scheme semiconductor photocatalysts for the photoelectrochemical applications: A review

Abstract

With continuous consumption of nonrenewable energy, solar energy has been predicted to play an essential role in meeting the energy demands and mitigating environmental issues in the future. Despite being green, clean and pollution-free energy, solar energy cannot be adopted directly as it cannot provide sufficiently high energy density to work in the absence of machinery.

Efficient and Sustainable in situ Photo‐Fenton Reaction to Remove Phenolic Pollutants by NH2‐MIL‐101(Fe)/Ti3C2Tx Schottky‐Heterojunctions

“…However, the weak conductivity of iron‐based MOF could inhibit the segregation efficiency of photogenerated carriers and accordingly reduce the photocatalytic performance [20] . Schottky‐heterojunction [21] with the built‐in electric field compared to other heterojunctions such as traditional Z‐scheme, [22] p‐n [23] and S‐scheme [24] can drive the photogenerated electrons (e − ) and holes (h + ) to move in the opposite direction. Moreover, the formed Schottky barrier can prevent the return of electrons, which both greatly separates the photogenerated e − ‐h + pairs and improves the concentration of free carriers [25] .…”

Dual Cocatalysts Synergistically Promote Perylene Diimide Polymer Charge Transfer for Enhanced Photocatalytic Water Oxidation

“…In particular, perylene diimide (PDI) systems have been found to be promising photocatalytic WOCs with broad spectral absorption, high photostability, and affordable cost. The deep valence bands of PDI materials contribute to their strong oxidizing ability, and the robust internal electric field and high crystallinity can promote the separation and migration of photogenerated charges. , However, the photocatalytic performance of a single catalyst is often restricted by some thermodynamic and dynamic barriers, which can be ameliorated through heterogeneous modifications. , Notably, transition metals and their oxides are often coupled to a photocatalyst as cocatalysts to restrain the electron–hole recombination and enhance the surface reactivity . Especially, Co-based composites (such as CoO x , Co­(OH) 2 , CoPi) are generally used as O 2 evolution cocatalysts to enhance the photocatalytic performance.…”

“…9,10 However, the photocatalytic performance of a single catalyst is often restricted by some thermodynamic and dynamic barriers, which can be ameliorated through heterogeneous modifications. 11,12 Notably, transition metals and their oxides are often coupled to a photocatalyst as cocatalysts to restrain the electron−hole recombination and enhance the surface reactivity. 13 Especially, Co-based composites (such as CoO x , 14 Co(OH) 2 , 15 CoPi 16 ) are generally used as O 2 evolution cocatalysts to enhance the photocatalytic performance.…”

Modulation of photogenerated holes for enhanced photoelectrocatalytic performance

“…In addition to the nanostructural modification of photoanodes, a highly conductive and active semiconductor can also be used directly on the photoanode surface to form a heterojunction photoelectrode. The construction of heterojunctions can effectively separate the photoelectron holes by satisfying the appropriate energy level positions between the two semiconductors (p-n/n-n) [43,44] . For lowenergy light-induced holes, Z-type nanocomposites have been successfully constructed by coupling suitable band gap semiconductors [45] .…”