Review on multi-dimensional assembled S-scheme heterojunction photocatalysts

S-scheme heterostructure photocatalysts utilize the synergistic and superposition effects of materials,ef-fectively separating electrons and holes,maintaining strong redox capacity,and addressing issues en-countered by current photocatalytic reactions.This review explores the origins and unique benefits of S-scheme heterojunctions.Specifically,we summarized and discussed the effects of different dimensions of semiconductors constituting S-scheme heterojunctions and the similarities and differences in elec-tron transfer processes when constructing heterojunctions.Additionally,we analyzed several methods for proving the formation of S-scheme heterojunctions and the electron transfer process,both directly and indirectly.Finally,we review the applications of S-scheme heterojunctions in various fields of photo-catalysis,including photocatalytic water splitting,pollution degradation,CO_(2) reduction and other related photocatalytic applications.Our hope is that this review will provide an essential reference for the devel-opment and application of S-scheme heterojunction photocatalysis.

Species,engineering and characterizations of defects in TiO2-basedphotocatalyst

Light absorption, charge separation and surface reaction are considered as the main processes ofphotocatalysis on one semiconductor, and all of them are demonstrated to be related to the defect statesof photocatalysts. This paper will choose Ti02 as model photocatalyst to introduce some basic conceptsand strategies related to defects and methods developed to characterize defects in the past decades.Meanwhile, such strategies as hydrogenation and metal/nonmetal doping intoTi02 will be introduced toextend utilization of solar spectrum and/or to provide active sites. On the contrary, the unfavorable effectof defects such as acting as recombination centers of photogenerated carriers will also be introduced.Some typical methods to characterize the properties of defects are summarized, which contain electronparamagnetic resonance （EPR）, photoluminescence technique （PL）, positron annihilation spectroscopy（PAS）, and so on. We do hope that this review will make a revealing effect on understanding to thefunctions of defects as well as construction of efficient photocatalytic systems in the future.

Ultrathin Co（Ni）-doped MoS2 nanosheets as catalytic promoters enabling efficient solar hydrogen production

The design of efficient artificial photosynthetic systems that harvest solar energy to drive the hydrogen evolution reaction via water reduction is of great importance from both the theoretical and practical viewpoints. Integrating appropriate co-catalyst promoters with strong light absorbing materials represents an ideal strategy to enhance the conversion efficiency of solar energy in hydrogen production. Herein, we report, for the first time, the synthesis of a class of unique hybrid structures consisting of ultrathin Co（Ni）-doped MoS2 nanosheets （co-catalyst promoter） intimately grown on semiconductor CdS nanorods （light absorber）. The as-synthesized one-dimensional CdS@doped-MoS2 heterostructures exhibited very high photocatalytic activity （with a quantum yield of 17.3%） and stability towards H2 evolution from the photoreduction of water. Theoretical calculations revealed that Ni doping can increase the number of uncoordinated atoms at the edge sites of MoS2 nanosheets to promote electron transfer across the CdS/MoS2 interfaces as well as hydrogen reduction, leading to an efficient H2 evolution reaction.

Progress in organic photocatalysts

Organic materials have advantages of diversity,ease of functionality, self-assembly, etc. The varied mechanistic pathways also make it conceivable to design an appropriate photocatalyst for an identical reaction. From this perspective, organic photocatalysts find wide applications in homogeneous, heterogeneous photocatalysis and photoelectrochemical（PEC） solar cells. In this review, the form of the employed organic photocatalysts ranging from molecules, supported molecules, to nanostructures or thinfilm aggregates will be firstly discussed. Rational design strategies relating to each form are also provided, aiming to enhance the photoenergy conversion efficiency. Finally,the ongoing directions for future improvement of organic materials in high-quality optoelectronic devices are also proposed.