Heterostructuring noble-metal-free 1T'phase MoS_(2) with g-C_(3)N_(4) hollow nanocages to improve the photocatalytic H2 evolution activity

In this work,we report the preparation of 1T'-MoS_(2)/g-C_(3)N_(4) nanocage(NC)heterostructure by loading 2D semi-metal noble-metal-free 1T'-MoS_(2) on the g-C_(3)N_(4) nanocages(NCs).DFT calculation and experimental data have shown that the 1T'-MoS_(2)/g-C_(3)N_(4) NC heterostructure has a stronger light absorption capacity and larger specific surface area than pure g-C_(3)N_(4) NCs and g-C_(3)N_(4) nanosheets(NSs),and the presence of the co-catalysts 1T'-MoS_(2) can effectively inhibit the photoinduced carrier recombination.As a result,the 1T'-MoS_(2)/g-C_(3)N_(4) NC heterostructure with an optimum 1T'-MoS_(2) loading of 9 wt%displays a hydrogen evolution rate of 1949 mmol h^(-1) g^(-1),162.4,1.2,1.5,1.6 and 1.2 times than pure g-C_(3)N_(4) NCs(12 mmol h^(-1) g^(-1)),Pt/g-C_(3)N_(4) NCs(1615 mmol h^(-1) g^(-1))and Pt/g-C_(3)N_(4) nanosheets(NSs,1297 mmol h^(-1) g^(-1)),1T'-MoS_(2)/g-C_(3)N_(4) nanosheets(1216 mmol h^(-1) g^(-1))and 2H-MoS_(2)/g-C_(3)N_(4) nanocages(1573 mmol h^(-1) g^(-1)),respectively,and exhibits excellent cycle stability.Therefore,1T'-MoS_(2)/g-C_(3)N_(4) NC heterostructure is a suitable photocatalyst for green H_(2) production.

The incorporation of cocatalyst cobalt sulfide into graphitic carbon nitride:Boosted photocatalytic hydrogen evolution performance and mechanism exploration

2D-layered graphitic carbon nitride(g-C_(3)N_(4))is regarded as a great prospect as a photocatalyst for H_(2)generation.However,g-C_(3)N_(4)’s photocatalytic hydrogen evolution(HER)activity is significantly restricted by the recombination of photocarriers.We find that cobalt sulfide(CoS_(2))as a cocatalyst can promote g-C_(3)N_(4)nanosheets(NSs)to realize very efficient photocatalytic H_(2)generation.The prepared CoS_(2)/g-C_(3)N_(4)hybrids display highly boosted photocatalytic H_(2)generation performance and outstanding cycle stability.The optimized 7%-CoS_(2)/g-C_(3)N_(4)hybrids show a much improved photocatalytic H_(2)generation rate of 36.2μmol-1h-1,which is about 180 times as much as bare g-C_(3)N_(4)(0.2μmol-1h-1).In addition,the apparent quantum efficiency(AQE)of all the samples was computed under light atλ=370 nm,in which the AQE of 7%-CoS_(2)/g-C_(3)N_(4)hybrids is up to 5.72%.The experimental data and the DFT calculation suggest that the CoS_(2)/g-C_(3)N_(4)hybrid’s excellent HER activity is attributable to the lower overpotential and the smaller Co-H bond activation energy for HER.Accordingly,the CoS_(2)cocatalyst loading effectively boosts the photocatalytic performance of g-C_(3)N_(4)for H_(2)evolution.The project promotes fast development of high-efficiency photocatalysts and low-cost for photocatalytic H_(2)generation.

Photocatalytic H2 Evolution on TiO2 Assembled with Ti3C2 MXene and Metallic 1T-WS2 as Co-catalysts

The biggest challenging issue in photocatalysis is efficient separation of the photoinduced carriers and the aggregation of photoexcited electrons on photocatalyst’s surface.In this paper,we report that double metallic co-catalysts Ti3C2 MXene and metallic octahedral(1T)phase tungsten disulfide(WS2)act pathways transferring photoexcited electrons in assisting the photocatalytic H2 evolution.TiO2 nanosheets were in situ grown on highly conductive Ti3C2 MXenes and 1T-WS2 nanoparticles were then uniformly distributed on TiO2@Ti3C2 composite.Thus,a distinctive 1T-WS2@TiO2@Ti3C2 composite with double metallic co-catalysts was achieved,and the content of 1T phase reaches 73%.The photocatalytic H2 evolution performance of 1T-WS2@TiO2@Ti3C2 composite with an optimized 15 wt%WS2 ratio is nearly 50 times higher than that of TiO2 nanosheets because of conductive Ti3C2 MXene and 1T-WS2 resulting in the increase of electron transfer efficiency.Besides,the 1T-WS2 on the surface of TiO2@Ti3C2 composite enhances the Brunauer–Emmett–Teller surface area and boosts the density of active site.

Au nanorods decorated TiO_(2)nanobelts with enhanced full solar spectrum photocatalytic antibacterial activity and the sterilization file cabinet application

TiO_(2)photocatalysts have been widely studied and applied for removing bacteria,but its antibacterial efficiency is limited to the ultraviolet(UV)range of the solar spectrum.In this work,we use the gold(Au)nanorods to enhance the visible and near-infrared(NIR)light absorption of TiO_(2)NBs,a typical UV light photocatalyst,thus the enhancement of its full solar spectrum(UV,visible and NIR)photocatalytic antibacterial properties is achieved.Preliminary surface plasmon resonance(SPR)enhancement photocatalytic antibacterial mechanism is suggested.On one hand,transverse and longitudinal SPR of Au NRs is beneficial for visible and NIR light utilization.On the other hand,Au NRs combined with TiO_(2)NBs to form the heterostructure,which can improve the photogenerated carrier separation and direct electron transfer increases the hot electron concentration while Au NRs as the electron channel can well restrain charge recombination.finally produces the high yield of radical oxygen species and exhibits a superior antibacterial efficiency.Furthermore,we design a sterilization file cabinet with Au NR/TiO_(2)NB heterostructures as the photocatalytic coating plates.Our study reveals that Au NR/TiO_(2)NB heterostructure is a potential candidate for sterilization of bacteria and archives protection.

Synthesis of porous few-layer carbon nitride with excellent photocatalytic nitrogen fixation

The porous few-layer g-C_(3)N_(4)(PFL-g-C_(3)N_(4))is prepared by a simple molecular self-assembly method.Compared with pure g-C_(3)N_(4),the as-prepared PFL-g-C_(3)N_(4) is ultrathin,the surface is rich in pores,and the photocatalytic nitrogen fixation activity is greatly increased to 8.20 mM h^(-1) gCat^(-1).Few-layer and ultrathin nature of PFL-g-C_(3)N_(4) can provide a larger specific surface area,expose more active sites,and reduce the diffusion path of charges and protons from the inside to the surface.In addition,the porous structure can narrow the band gap,thereby increasing the light absorption range and enhancing the light absorption capability.Meanwhile,the presence of nitrogen vacancies causes PFL-g-C_(3)N_(4) to move to a more negative conductive band value.More importantly,the isotopic experiments using ^(15)N_(2) as nitrogen source confirm the ammonia production originating from N2 rather than the decomposition of g-C_(3)N_(4).Therefore,PFL-g-C_(3)N_(4) can greatly improve the efficiency of visible light photocatalytic nitrogen fixation.

The metallic 1T-WS_(2)as cocatalysts for promoting photocatalytic N_(2) fixation performance of Bi_(5)O_(7)Br nanosheets

Recently,widespread attention has been devoted to the typical layered BiOCl or BiOBr because of the suitable nanostructure and band structure.However,owing to the fast carrier recombination,the photocatalytic performance of BiOX materials is not so satisfactory.Loading 1T phase WS_(2)nanosheets(NSs)onto Bi_(5)O_(7)Br NSs can improve the photocatalytic N_(2)fixation activity.Among these,the obtained 1T-WS_(2)@Bi_(5)O_(7)Br composites with optimum 5%1T-WS_(2)NSs display a significantly improved photocatalytic N_(2)fixation rate(8.43 mmol L^(−1)h^(−1)g^(−1)),2.51 times higher than pure Bi_(5)O_(7)Br(3.36 mmol L^(−1)h^(−1)g^(−1)).And the outstanding stability of 1T-WS_(2)@Bi_(5)O_(7)Br-5 composites is also achieved.Exactly,the photoexcited electrons from Bi_(5)O_(7)Br NSs are quickly transferred to conductive 1T phase WS_(2)as electron acceptors,which can promote the separation of carriers.In addition,1T-WS_(2)NSs can provide abundant active sites on the basal and edge planes,which can promote the efficiency of photocatalytic N_(2)fixation.This work offers a novel solution to improve the photocatalytic performance of Bi_(5)O_(7)Br NSs.