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The undercoordinated Pb2+ sites on a CsPbBr3 surface would induce serious instability issue. Here we demonstrate a facile method to eliminate the undercoordinated Pb2+ sites of CsPbBr3 for photocatalytic CO2 reduction. The SO42– ions can bond with the surface Pb2+ sites, thus forming a water-insoluble PbSO4. The surface PbSO4 can effectively improve the water resistance and decrease the defects of CsPbBr3 nanocrystals (NCs). The resultant CsPbBr3–SO4 NCs exhibit an improved photocatalytic activity toward CO2 reduction, which is about 8 times higher than that of the CsPbBr3 NCs. This work highlights the importance of surface modification on improving the photoelectronic properties of perovskites. [ABSTRACT FROM AUTHOR]

As an emerged photocatalyst, perovskites have attracted enormous interest in photocatalysis due to their excellent photoelectronic properties. However, most of the photoexcited electron–hole pairs recombine together before they reach the surface of perovskite for photocatalysis. The undesired charge recombination would compete with the surface photocatalytic reaction. Hence, the regulation of charge carriers is essential for improving the photocatalytic performance of perovskites. Herein, the charge transfer dynamics by doping Mn2+ in CsPbCl3 perovskite nanocrystals (NCs) is manipulated and the role of the charge carriers with a prolonged lifetime in photocatalysis is investigated. The photogenerated charge carriers with a prolonged lifetime at both Mn2+ dopants and conduction band (CB) endow Mn:CsPbCl3 NCs with an enhanced photocatalytic activity toward CO2 reduction. The doping strategy provides us with a powerful tool to regulate the charge transfer dynamics in perovskite NCs for photocatalysis. It is believed that the long‐lived charge carriers in perovskite NCs have great potential in promoting charge separation and suppressing charge recombination in solar‐to‐fuel conversions. [ABSTRACT FROM AUTHOR]

Metal halide perovskite (MHP) nanocrystals (NCs) have shown promising application in photocatalytic CO2 reduction, but their activities are still largely restrained by severe charge recombination and narrow solar spectrum response. Assembly of heterojunctions can be beneficial to the charge separation in MHPs while the assembly process usually brings native interfacial defects, impeding efficient charge separation between two materials. Herein, an in‐situ generation strategy was developed to prepare CsPbBr3/WO3 heterojunction, using WO3 nanosheets (NSs) as growing substrate for the growth of CsPbBr3 NCs. The developed CsPbBr3/WO3 heterojunction exhibited a high‐quality interface, greatly facilitating charge transfer between two semiconductors. The hybrid photocatalyst displayed an excellent activity toward CO2 reduction, which was about 7‐fold higher than pristine CsPbBr3 NCs and 3.5‐fold higher than their assembled counterparts. The experimental results and theoretical simulations revealed that a Z‐scheme mechanism with a favorable internal electric field was responsible for the good performance of CsPbBr3/WO3 heterojunction. By using O‐defective WO3 NSs as a near‐infrared (NIR) light absorber, the CsPbBr3/WO3 heterojunction could harvest NIR light and showed an impressive activity toward CO2 reduction. This work demonstrates a new strategy to design MHP‐based heterojunctions by synergistically considering the interface quality, charge transfer mode, interfacial electric field, and light response range between two semiconductors. [ABSTRACT FROM AUTHOR]

Photocatalytic reduction of CO2 into value‐added chemical fuels is an appealing approach to address energy crisis and global warming. CsPbBr3 quantum dots (QDs) are good candidates for CO2 reduction because of their excellent photoelectric properties, including high molar extinction coefficient, low exciton binding energy, and defect tolerance. However, the pristine CsPbBr3 QDs generally have low photocatalytic performance mainly due to dominant charge recombination and lack of efficient catalytic sites for CO2 adsorption/activation. Herein, we report a new photocatalytic system, in which CsPbBr3 QDs are coupled with covalent triazine frameworks (CTFs) for visible‐light‐driven CO2 reduction. In this hybrid photocatalytic system, the robust triazine rings and periodical pore structures of CTFs promote the charge separation in CsPbBr3 and endow them with strong CO2 adsorption/activation capacity. The resulting photocatalytic system exhibits excellent photocatalytic activity towards CO2 reduction. This work presents a new photocatalytic system based on CTFs and perovskite QDs for visible‐light‐driven CO2 reduction, which highlights the potential of perovskite‐based photocatalysts for solar fuel applications. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs), a class of promising candidates for harvesting visible light, generally exhibit low activity and selectivity towards photocatalytic CO2 reduction. Functionalizing QDs with metal complexes (or metal cations through ligands) is a widely used strategy for improving their catalytic activity; however, the resulting systems still suffer from low selectivity and stability in CO2 reduction. Herein, we report that doping CdS QDs with transition‐metal sites can overcome these limitations and provide a system that enables highly selective photocatalytic reactions of CO2 with H2O (100 % selectivity to CO and CH4), with excellent durability over 60 h. Doping Ni sites into the CdS lattice leads to effective trapping of photoexcited electrons at surface catalytic sites and substantial suppression of H2 evolution. The method reported here can be extended to various transition‐metal sites, and offers new opportunities for exploring QD‐based earth‐abundant photocatalysts. Quantum dots (QDs), a class of promising nanoparticles for visible‐light harvesting, commonly possess low activity and selectivity towards photocatalytic CO2 reduction. Doping CdS QDs with transition‐metal cations, which can trap photoexcited electrons and suppress H2 evolution, provides an approach to visible‐light‐driven highly selective CO2 reduction with excellent durability. [ABSTRACT FROM AUTHOR]

Incorporation of Pd into Pt co‐catalysts is demonstrated as an approach to improve water splitting performance by employing TiO2 nanosheets as a semiconductor model. Theoretical simulations reveal that interatomic polarization between Pd and Pt may play a role in facilitating adsorption of molecular water and activation on Pt reaction sites. [ABSTRACT FROM AUTHOR]

Abstract: Graphitic carbon nitride (g‐C3N4) coupled with Bi2WO6 is a promising Type II heterojunction, but it is still difficult to obtain uniform nanocomposites of these materials with the present assembly methods. Here we employ g‐C3N4 nanosheets saturated with Bi3+ ions to provide numerous and widespread nucleation sites for the growth of Bi2WO6 nanocrystals. As a result, g‐C3N4 nanosheets loaded with fine and controllable amount of Bi2WO6 nanocrystals are produced. The g‐C3N4/Bi2WO6 nanocomposites exhibit significantly enhanced photocatalytic activity for RhB degradation under visible‐light irradiation. Particularly, the g‐C3N4/70 % Bi2WO6 nanocomposite achieves the highest photocatalytic activity, and the average rate constant is almost 5 and 9 times higher than those of bare g‐C3N4 and Bi2WO6, respectively. Moreover, the composite exhibits high photocatalytic stability in cycling tests. [ABSTRACT FROM AUTHOR]

Abstract: Surfaces and interfaces are two key parameters to maneuver the performance of photocatalytic materials, particularly for hybrid structures, in various reaction systems. In this Focus Review, we highlight the recent progress on surface and interface engineering toward designing highly efficient photocatalysts, and elucidate the fundamental principles behind the designs. We first introduce the roles of surfaces and interfaces in different models of charge kinetics—a key process determining the quantum efficiency of photocatalysis—followed by the definitions of surface and interface in basic photocatalytic architectural structures. We then outline the design rules and important parameters for surface and interface engineering, respectively. As an interplay effect, the relationships between surface and interface parameters in photocatalyst design are also presented. We further summarize the synthetic methods for surface and interface control. Finally, we discuss the challenges and opportunities for photocatalysis research in terms of surface and interface engineering. [ABSTRACT FROM AUTHOR]

[Display omitted] All-inorganic lead-free halide double perovskites have emerged as rising star photocatalysts to substitute the toxic lead-based hailed perovskites (LHPs) owing to their unique photophysical properties. Nevertheless, their photocatalytic activities toward CO 2 reduction are still far from comparable with the LHPs, associated with severe charge recombination and sluggish surface catalytic reaction. Herein, a delicate 0D/2D heterojunction of Cs 2 AgBiBr 6 /Bi 2 WO 6 (CABB/BWO) was assembled by in-situ growing cubic CABB nanocrystals on the flat surface of BWO nanosheets via a facile hot-injection method. Density functional theory (DFT) calculations disclose that the work function and Fermi level difference between CABB and BWO give rise to charge redistribution at the interface upon the formation of the heterojunction, creating an internal electric field (IEF). Upon light irradiation, the IEF enables the photogenerated electron transfer from BWO to CABB via direct Z-scheme electron transfer mode with striking spatial charge separation as verified by in-situ X-ray photoelectron (XPS) and electron spin resonance (ESR) spectra. Consequently, the CABB/BWO heterojunction realizes 7-fold higher photocatalytic activity than pristine CABB with significant electron consumption rate of 87.66 µmol g-1h−1 under simulated solar light (AM 1.5G). [ABSTRACT FROM AUTHOR]

Coupling CO 2 reduction with selective organic hydrocarbon oxidation using semiconductor photocatalysts holds significant importance in achieving carbon neutrality and obtaining valuable chemical raw materials. Nevertheless, finding a potential single photocatalyst with sufficient redox potentials capable of simultaneously driving redox reactions poses a formidable challenge. Herein, a distinct heterostructure of W 18 O 49 /CsPbBr 3 was meticulously fabricated through the in-situ growing of CsPbBr 3 nanocrystal on bundle-like W 18 O 49 ultrathin nanowires via the hot-injection method. Experimental and theoretical characterizations reveal the establishment of a solid internal electric field at the heterojunction interface, enabling spatial charge separation via a valid interfacial S-scheme with strong redox ability. The W 18 O 49 /CsPbBr 3 heterostructure demonstrated decent performance, yielding high production of CO (143 μmol g−1 h−1) and selective oxidizing toluene to benzaldehyde (1546 μmol g−1 h−1) with an 80% selectivity. This work may pave a rational way for fully exploiting the potentials of photogenerated carriers in the heterojunction photocatalysts in synergetic photocatalytic systems. [Display omitted] • An S-scheme heterostructure of W 18 O 49 /CsPbBr 3 is designed via an in-situ growth method with spatial charge separation. • Remarkable bifunctional photocatalytic productions of CO and selective oxidizing toluene to benzaldehyde with high selectivity are achieved. • Comprehensive characterizations confirm that an effective S-scheme charge transfer mode is built. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Photocatalytic degradation of environmental pollutants by using semiconductor-based photocatalysts offers great potential for remediation of toxic chemicals. For an economical and eco-friendly method to eliminate hexavalent chromium (Cr(VI)), favourable catalysts own high efficiency, stability and capability of harvesting light. Combination of metal with semiconductor is a promising route to improve the photocatalytic performance for Cr(VI) reduction. Herein, well-dispersed platinum (Pt) nanocubes (NCs) were synthesized by a facile one-step hydrothermal method with poly- l -lysine (PLL) as the growth-directing agent, followed by their uniform dispersion on graphitic carbon nitride (g-C 3 N 4). Their morphology, crystal structure, chemical composition, and formation mechanism were mainly characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The hybrid nanocomposite was further explored for photocatalytic reduction of Cr(VI) to trivalent chromium (Cr(III)) under visible light at room temperature, by using formic acid (HCOOH) as a reducing agent, showing great improvement in photocatalytic activity and reusability, outperforming the referenced g-C 3 N 4 and home-made Pt black/g-C 3 N 4 catalysts. The effects of various experimental parameters and the proposed mechanism are discussed in detail. [ABSTRACT FROM AUTHOR]

Upconversion (UC) NaYF 4 :Yb,Tm nanocrystals (NCs) are capable of converting low-energy near-infrared (NIR) photons to high-energy ultraviolet (UV) and visible (Vis) photons. Integration of NaYF 4 :Yb,Tm with graphitic carbon nitride (g-C 3 N 4 ) can extend the spectral response of g-C 3 N 4 to the NIR range. However, photocatalytic activity of NaYF 4 :Yb,Tm/g-C 3 N 4 is still severely limited by the high recombination rate of photo-generated (PG) electrons and holes (e – /h + ) in the g-C 3 N 4 . Herein, we report a facile approach to fabricate a ternary nanocomposite consisting of NaYF 4 :Yb,Tm, TiO 2 and g-C 3 N 4 . When NaYF 4 :Yb,Tm NCs were coated with a TiO 2 shell and sequentially assembled with g-C 3 N 4 nanosheets (NSs), a semiconductor heterojunction can be fabricated on the UC particles. The as-prepared nanocomposites possess an enhanced photocatalytic activity under Vis and/or NIR lights due to the formation of heterojunction and UC effect. The ternary nanocomposites have been characterized in detail and their photocatalytic mechanism is proposed. Such kind of ternary nanocomposites may provide a new scenario for the design and synthesis of composite photocatalysts for efficiently utilizing the Vis/NIR lights in environmental remedy. [ABSTRACT FROM AUTHOR]

ZnO is one of the most promising materials for both photocatalytic and antibacterial applications, but its wide bandgap requires the excitation of UV light which limits their applications under visible and NIR bands. Herein, we demonstrate a facile approach to synthesize core-shell-shell hybrid nanoparticles consisting of hexagonal NaYF 4 :Yb,Tm, amorphous SiO 2 and wurtzite ZnO. The upconversion nanocrystals are used as the core seeds and sequentially coated with an insulting shell and a semiconductor layer. Such hybrid nanoparticles can efficiently utilize the NIR light through the upconverting process, and display notable photocatalytic performance and antibacterial activity under NIR irradiation. The developed NaYF 4 :Yb,Tm@SiO 2 @ZnO nanoparticles are characterized with TEM, XRD, EDS, XPS and PL spectra, and their working mechanism is also elucidated. [ABSTRACT FROM AUTHOR]

Decreasing the shell thickness of TiO 2 hollow spheres is a promising route to achieve an overall enhanced photocatalytic performance. However, in traditional synthetic approaches, the thin shell can not guarantee the structural stability of the TiO 2 hollow spheres in the following calcination process to achieve a high degree of crystallinity. In this paper, ultrathin porous TiO 2 hollow spheres with good structural stability, high degree of crystallinity as well as in small grain size were prepared through a novel etching and reconstruction route using amorphous SiO 2 /TiO 2 hollow spheres as precursor. With hot water as etchant, the removal of SiO 2 leads to the reconstruction of TiO 2 hollow spheres and receiving a thinner and thinner shell. Such thin shell enables the exposure of more catalytic active sites of TiO 2 nanocrystals and the improved photogenerated charge transfer and separation. Meanwhile, the residual SiO 2 on the TiO 2 shell protects the TiO 2 nanocrystals from growing larger during high-temperature calcinations. The as-obtained ultrathin porous TiO 2 hollow spheres exhibited enhanced photocatalytic activity in hydrogen production from water in comparison with those with thicker shell. [ABSTRACT FROM AUTHOR]

α-Fe 2 O 3 nanoparticles-decorated ZnO nanorod-assembled hollow spheres were successfully synthesized by a simple acetone-assisted impregnation deposition. SEM images showed a uniform distribution of α-Fe 2 O 3 nanoparticles not only on the surfaces of ZnO spheres but also inside pores of ZnO parallel aligned nanorods. The α-Fe 2 O 3 /ZnO binary semiconductor composites exhibited a superior visible-light photocatalytic activity for degradation of rhodamine B (RhB) as compared with pure ZnO spheres. The enhancement was attributed to stronger visible light absorption ability and effective photogenerated charge separation of α-Fe 2 O 3 /ZnO composites. [ABSTRACT FROM AUTHOR]

[Display omitted] • Six possible stacking patterns of the PtSe 2 /hBNC vdW heterojunction are studied. • PtSe 2 /hBNC has good thermodynamic, kinetic and mechanical stability. • Type-Ⅱ heterojunction has effectively enhanced the photocatalytic activity. • PtSe 2 /hBNC possesses marvelous carrier mobility and OER efficiency. Designing and researching suitable photoelectrocatalyst for water splitting is crucial for the utilization of renewable and inexhaustible solar energy but remains a huge conundrum. Here, using first principles calculations, the two-dimensional PtSe 2 /hBN heterojunction was first conceived. However, the rapid recombination of electrons and holes will inhibit the visible light catalytic efficiency of the heterojunction. In order to realize effective spatial separation of electrons and holes of the heterojunction, we tuned the band gap by doping two carbon atoms on the hBN monolayer to obtain the type-Ⅱ PtSe 2 /hBNC heterojunction. Then through the comprehensive researches on structural, electronic and optical properties, it was found that the structure possesses excellent carrier mobility and exhibits a great oxygen evolution reaction performance with a low overpotential of 0.76 eV, which is an ideal photoelectrocatalyst and exhibits great light absorption performance. In this study, the possible mechanism of doped PtSe 2 /hBNC vdW heterojunction to promote photocatalysis and oxygen evolution ability was explained, which may pave the way for the practical design of more solar-driven high-quality water splitting photoelectrocatalysts. [ABSTRACT FROM AUTHOR]

A CdS/MoS 2 photocatalyst was fabricated via a facile photodeposition method for efficient H 2 generation. • MoS 2 is directly grown onto the CdS QD by a facile photodeposition method. • The intimate interfacial contact promotes the charge transfer between CdS and MoS 2. • The MoS 2 provide abundant catalytic sites for CdS QDs towards H 2 evolution. • The CdS/MoS 2 composites exhibit excellent catalytic performance. Photocatalytic hydrogen (H 2) production from water is an appealing approach to alleviate the ever-increasing fossil fuel crisis. The development of visible-light-driven photocatalytic system is an essential task for H 2 generation. CdS quantum dots (QDs) are excellent candidate for photocatalytic H 2 generation. However, the photocatalytic performance of CdS QDs is largely limited by serious charge recombination and photocorrison problems. Herein, we developed a facile method for photodeposition of MoS 2 onto CdS QDs. The in-suit photodeposition approach enables thin-layered MoS 2 to be intimately decorated onto the CdS QD surface. The intimate contact favors the formation of junctions between CdS and MoS 2 , thus promoting charge separation in CdS/MoS 2. Furthermore, the MoS 2 catalysts can provide highly active catalytic sites for H 2 evolution and serve as protective layer for CdS to restrict photocorrison. The resulted CdS/MoS 2 photocatalysts exhibit excellent catalytic activity: the H 2 generation rate reaches 13129 μmol h−1 g−1, which is 7.2 times higher than that of the pristine CdS-S QDs. The CdS/MoS 2 photocatalysts also possess superior photocatalytic durability under visible light. This work provides a novel method for in-suit growth of MoS 2 onto QDs. The surface modification strategy presented here offers new opportunities for developing new-types of photocatalysts based on QDs. [ABSTRACT FROM AUTHOR]

• Bimetallic phosphide nanotubes with tunable Fe/Ni ratio are developed. • Efficient photocatalytic H 2 and O 2 generation are realized on Fe-Ni-P nanotubes. • Photocatalytic activities of Fe-Ni-P nanotubes can be regulated by the Fe/Ni ratio. • Working mechanism of the tunable dye-sensitized system is illustrated. Dye-sensitized systems show promising in photocatalysis because they can separate the tasks of light absorption, charge generation and surface catalysis to two coupled components. In this system, it is crucial to develop suitable catalysts capable of receiving dye-injected charges and having high activity to a given reaction. Aiming to photocatalytic H 2 and O 2 production, we present a metal-organic framework derived route to prepare bimetallic Fe-Ni-P nanotubes using Fe-Ni-MIL-88 nanorods as templates. When integrated with different dyes, these Fe-Ni-P nanotubes can serve as efficient catalysts for photocatalytic H 2 and O 2 production, respectively. Additionally, catalytic activities of such dye-sensitized systems can be conveniently regulated by tailoring the metal compositions in Fe-Ni-P nanotubes. The photocatalytic H 2 production of Fe 1 -Ni 2 -P can reach 5420 μmol g cat −1 h−1 under eosin-Y sensitization, which is 24 times and 6.7 times higher than Fe 2 P and Ni 2 P, respectively. The photocatalytic O 2 production of Fe 1 -Ni 2 -P can reach 900.3 μmol g cat −1 h−1 under [Ru(bpy) 3 ]Cl 2 sensitization, about 4.6 times and 2.9 times higher than Fe 2 P and Ni 2 P. The roles of different components in the system have been explored and corresponding working mechanism is proposed. This work demonstrates a new type of dye-sensitized systems consisting of bimetallic phosphides and provides a facile route to regulate their photocatalytic performance. [ABSTRACT FROM AUTHOR]

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