Search

The contact degree of heterojunction plays a crucial role to the separating efficiency of photo-generated carriers. Herein, a nano-sheet like BiOBr/Bi24O31Br10 lattice heterojunction is firstly prepared from a simple solid-state chemical reaction. The phase transformation from BiOBr to BiOBr/Bi24O31Br10, then to pure Bi24O31Br10 can be realized simply by the thermal annealing process. Benefiting from the enhanced photoinduced carrier separation efficiency of the formed lattice heterojunction, the BiOBr/Bi24O31Br10 composite exhibites excellent photocatalytic capability to reduce CO2 to CO, which has a stable yield of CO (29.19 μmol g−1) after 5 h of continuous catalytic reaction, the reaction rate constants are 4.2 and 3.5 times higher than that of pure Bi24O31Br10 and BiOBr, respectively. Meanwhile, the heterostructures present super photocatalytic degradation ability for rhodamine B (RhB) under visible light. The mechanism of the photocatalytic reduction and oxidation process is systematically investigated and proposed. This work provides an effective strategy to design staggered heterojunction photocatalyst by a solvent-free method and reveals the mechanism of lattice heterostructure for boosting photocatalytic performance. [ABSTRACT FROM AUTHOR]

Heterojunction engineering is a fundamental strategy to develop efficient electrocatalysts for the oxygen reduction reaction by tuning electronic properties through interfacial cooperation. In this study, a heterojunction electrocatalyst consisting of bimetallic carbide Co3ZnC and cobalt encapsulated within N‐doped carbon nanotubes (Co3ZnC/Co@NCNTs) is synthesized by a facile two‐step ion exchange‐thermolysis pathway. Co3ZnC/Co@NCNTs effectively promotes interfacial charge transport between the different components with optimizes adsorption and desorption of intermediate products at the heterointerface. In situ‐grown N‐doped carbon nanotubes (NCNTs) not only improve the electrical conductivity but also suppress the oxidation of transition metal nanoparticles in alkaline media. Moreover, the abundant nitrogen types (pyridinic N, Co−Nx, and graphitic nitrogen) in the carbon skeleton provide more active sites for oxygen adsorption. Benefitting from this optimized structure, Co3ZnC/Co@NCNTs hybrid not only demonstrates excellent oxygen reduction activity, with a half‐wave potential of 0.83 V and fast mass transport with limited current density of 6.23 mA cm−2, but also exhibits superior stability and methanol tolerance, which surpass those of commercial Pt/C catalysts. This work provides an effective heterostructure for interfacial electronic modulation to improve electrocatalytic performance. [ABSTRACT FROM AUTHOR]

Cobalt-embedded N-doped carbon nanotubes (Co@NCNT) synthesized by one-step thermal decomposition was used anchoring sites for heterojunction and carbon carrier, and heterogeneous structural Co 2 P/CoP nanospheres embedded in N-doped carbon nanotubes to form interpenetrated interface with Co@NCNT have been successfully fabricated by a controlled phosphatization, which exhibits a superior bifunctional performance for HER and OER. [Display omitted] • The Co@NCNT is synthesized by one-step thermal decomposition. • The Co@NCNT is used as anchoring sites for heterojunction and carbon carrier. • A rich-interface Co 2 P/CoP@Co@NCNT is fabricated by a controlled phosphatization. • Co 2 P/CoP embedded in Co@NCNT inhibits the fall off and aggregation of catalyst. • The Co 2 P/CoP@Co@NCNT exhibites the superior bifunctional activity and stability. Constructing heterostructures with rich-interface by the interfacial electron modulating is the key to integrating the rich functionalities for elcetrocatalysis. Herein, heterogeneous structural Co 2 P/CoP hollow nanospheres embedded in N-doped carbon nanotubes (Co 2 P/CoP@Co@NCNT) to form a rich-interface catalyst is fabricated by a controlled phosphatization. Experimental results manifest that the metallic cobalt embedded in N-doping carbon nanotubes by one-step thermal decomposition can be used as anchoring sites for heterojunction and carbon carrier, thus providing abundant active sites, accelerating the electrical conductivity. Besides, the self-assembled Co 2 P/CoP hollow nanospheres was embedded on the surface of Co@NCNT, which is conducive to the formation of more interfaces, and adjusting the surface electronic structure. Benefiting from the synergies between Co 2 P, CoP and Co@NCNT, the as-synthesized Co 2 P/CoP@Co@NCNT exhibits enhanced active sites and increased intrinsic activity, resulting in a better bifunctional performance in 1.0 M KOH, only requiring overpotentials of 118 and 256 mV to deliver a current density at 10 mA cm−2 for HER and OER, respectively. As cathodes, it also delivers low η 10 values of 136 mV in 0.5 M H 2 SO 4. Moreover, a two-electrode electrolyzer assembled by Co 2 P/CoP@Co@NCNT presents a cell voltage of 1.6 V at 10 mA cm−2 with impressive long-life cycling stability, showing great potential for economical and scalable water splitting application. [ABSTRACT FROM AUTHOR]

The synergistic interaction between sulfur-containing CdS nanoparticles and Co@NCNT enhanced the activity and stability of the photocatalytic CO 2 reduction reaction. COOH* is a crucial intermediate for reducing CO 2 to carbonaceous compounds. [Display omitted] • CdS nanoparticles with sulfur vacancies were grown on Co@NCNT by a simple solvothermal method. • The synergistic effect between CdS-S V nanoparticles and Co@NCNT demonstrated outstanding photocatalytic CO 2 reduction performance. • Co@NCNT inhibited the photocorrosion and enhanced the stability of CdS. The structural devise of photocatalytic materials are closely related to the separation of photogenerated carriers and the transport of charge, which is crucial to enhance the performance of photocatalytic carbon dioxide reduction reaction (CO 2 RR). Here, a photocatalyst (CdS-S V @Co@NCNT) has been successfully prepared by growing cadmium sulfide nanoparticles with sulfur vacancies on N-doped carbon nanotubes through a simple solvothermal method. The intrinsic electronic structure is regulated by sulfur vacancies to promote photocatalytic activity. Meanwhile, a larger specific surface area of Co@NCNT could expose more reaction sites and shorten the transfer distance of photogenerated carriers. Furthermore, the combination with Co@NCNT could effectively suppress the photocorrosion of CdS. The possible photocatalytic CO 2 RR path is further speculated by in-situ infrared test results, in which CO 2 molecules adsorbed on sulfur vacancies preferentially generate important intermediate COOH*, which is then reduced to CO and CH 4. Therefore, it exhibits a high CO yield of 263.3 μmol·g−1·h−1 and trace of CH 4 while showing excellent stability. This research provides a novel idea for designing the photocatalysts with highly active and stability for CO 2 RR. [ABSTRACT FROM AUTHOR]

[Display omitted] • Highly efficient piezocatalysts of CdS/BiOCl S-scheme heterojuction were rationally designed. • Optimized CdS/BiOCl endowed excellent piezocatalytic activity and stability toward H 2 evolution and organic pollutants degradation. • S-scheme charge transfer mechanism was demonstrated via electron paramagnetic resonance and Quasi-In-situ X-ray photoelectron spectroscopy measurements. • An innovative piezocatalytic mechanism of CdS/BiOCl S-scheme heterojunction was clarified. Piezocatalysis as an emerging technology is broadly applied in hydrogen evolution and organic pollutants degradation aspects. However, the dissatisfactory piezocatalytic activity is a severe bottleneck for its practical applications. In this work, CdS/BiOCl S-scheme heterojunction piezocatalysts were constructed and explored the performances of piezocatalytic hydrogen (H 2) evolution and organic pollutants degradation (methylene orange, rhodamine B and tetracycline hydrochloride) under strain by ultrasonic vibration. Interestingly, CdS/BiOCl presents a volcano-type relationship between catalytic activity and CdS contents, namely firstly increases and then decreases with the increase of CdS content. Optimal 20 % CdS/BiOCl endows superior piezocatalytic H 2 generation rate of 1048.2 μmol g−1h−1 in methanol solution, which is 2.3 and 3.4 times higher than that of pure BiOCl and CdS, respectively. This value is also much higher than the recently reported Bi-based and most of other typical piezocatalysts. Meanwhile, 5 % CdS/BiOCl delivers the highest reaction kinetics rate constant and degradation rate toward various pollutants compared with other catalysts, which also exceeds that of the previously numerous results. Improved catalytic capacity of CdS/BiOCl is mainly ascribed to the construction of S-scheme heterojunction for enhancing the redox capacity as well as inducing more effective charge carriers separation and transfer. Moreover, S-scheme charge transfer mechanism is demonstrated via electron paramagnetic resonance and Quasi-In-situ X-ray photoelectron spectroscopy measurements. Eventually, a novel piezocatalytic mechanism of CdS/BiOCl S-scheme heterojunction has been proposed. This research develops a novel pathway for designing highly efficient piezocatalysts and provides a deeper understanding in construction of Bi-based S-scheme heterojunction catalysts for energy conservation and wastewater disposal applications. [ABSTRACT FROM AUTHOR]

The In(OH) 3 -TiO 2 nanostructures were synthesized by solid-state synthesis at room temperature and exhibited apprecible photocatalytic hydrogen evolution activity. [Display omitted] • The In(OH) 3 -TiO 2 structure was constructed by solid-state strategy under room temperature condition. • The resulting In(OH) 3 -TiO 2 heterojunction simultaneously tailor band structure and accelerate charge separation. • The as-synthesized photocatalyst displays favorable photocatalytic activity and is 15.7-fold superior to commercial TiO 2. The convenient modification of transition metal and the simultaneous adjustment of energy band are effective measures to improve the photocatalytic activity of titanium dioxide but remains challenging in photocatalytic hydrogen evolution field. Herein, In(OH) 3 -TiO 2 heterostructures were constructed by solid-state synthetic strategy under room temperature for tuning the band structure and accelerating the photoexcited charge separation to enhance the photocatalytic activity for hydrogen evolution. By the quantified modification of In(OH) 3 , the obtained In(OH) 3 -TiO 2 delivers an appreciable photocatalytic activity and stability for hydrogen evolution, which is 15.7 folds superior to commercial P25. Due to the narrowed band gap, the increased charge carrier density, the restrained recombination rate of photoexcited electron-hole pairs and the accelerated photogenerated charge separation, the In(OH) 3 -TiO 2 heterostructures thereby achieve the boosted photocatalytic hydrogen evolution performance. This work provides a feasible strategy to enhance the photocatalytic hydrogen evolution of TiO 2 via tuning the band gap and accelerating the photoinduced charge separation. [ABSTRACT FROM AUTHOR]

A molecular-cage strategy is employed to encapsulate H 3 PMo 12 O 40 into cavities of ZIF-67. The fabricated Pt-Mo 6 Co 6 C heterojunctions uniformly embedded on dodecahedron carbon matrix and exhibit superior HER activity and stability than commercial Pt/C in universal PH solutions. [Display omitted] • A cage-confinement strategy was employed to encapsulate H 3 PMo 12 O 40 cluster into cavities of ZIF-67 without destroy its structure. • The Mo 6 Co 6 C nanoparticles was homogeneously embedded on dodecahedron carbon matrix without aggregation during pyrolysis process. • The Pt-Mo 6 Co 6 C heterojunction was fabricated through galvanic replacement which presents superior HER activity than commercial Pt/C in PH-universal solutions. • DFT calculation suggested that hydrogen adsorption free energy (ΔG H*) of Pt-Mo 6 Co 6 C heterojunction delivered a closer value to 0 eV than metallic Pt. Electrochemical water splitting has been highly considered as a promising technology to produce hydrogen with high purity and large quantity. Herein, a cage-confinement strategy is proposed to encapsulate H 3 PMo 12 O 40 clusters into cavities of ZIF-67. The ZIF-67 with cavity diameter of 1.16 nm and cavity window of 0.34 nm can appropriately confine H 3 PMo 12 O 40 with diameter of 1.0 nm. The H 3 PMo 12 O 40 served as guest species were also homogeneously encapsulated in well-defined cavities of ZIF-67 host without destroying the structure of ZIF-67. This cage-confinement strategy endow Mo 6 Co 6 C nanoparticles uniformly embedded in carbon matrix without aggregation and exposed abundant active sites during pyrolysis process. Furthermore, the heterojunction of Pt-Mo 6 Co 6 C was fabricated through galvanic replacement with H 2 PtCl 6. The prepared Pt-PMo/ZIF-67-800 electrocatalyst with a low Pt amount of 3.0 % exhibits excellent HER activity and stability and even superior to commercial Pt/C in PH-universal solutions. Density functional theory (DFT) calculation reveals that Pt-Mo 6 Co 6 C heterostructure results in a lower hydrogen adsorption free energy than commercial Pt/C and thus enhances its intrinsic catalytic activity. The outstanding HER performance of Pt-Mo 6 Co 6 C heterostructure confined on dodecahedron carbon matrix opens new perspectives for rational design polyoxometalate (POM) based catalyst for hydrogen evolution. [ABSTRACT FROM AUTHOR]